practical improvement planning for factories

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10

Practical Improvement

Planning for Factories

Mohsen Faizollahi



Abstract

Title: Practical improvement planning for factories

Author: Mohsen Faizollahi

Background: Lean Production is a multi-dimensional method for improving competency

benefits which consider a broad range of manufacturing methods in unified system. Some of

these techniques include JIT (Just in Time) manufacturing, Standardization of methods of

manufacturing, reduction of inventory/ reduction of inventory during the production and

reducing production batches, reducing preparing time/ reducing set-up time, pull system,

quality improvement, related issues to human resources, 5Ss and supply chain management.

The important thing is that these methods are able to have comprehensive and coordinated

effect on production or service organizations and consequently final product/service will be

delivered without lost (In term of Lean Production is called Muda) or with less waste withincustomer demand will be produced. Muda is a term that continuous elimination of it is the

underpinning of Lean Thinking in Operation and Production Management. It is any activity

which consumes resources without any value added to the customer. Philosophy of Lean

Thinking and Production depends upon continual elimination of Muda which will result to

creation of values in point of customer satisfaction.

Purpose: The main goal of this paper emphasizes on achieving a well-organized guidance in

manufacturing area in order to identify major barriers to implement the lean concept in the

work area. Although, the implementation of lean production could be done by a professional

organization via sponsors a work shop at a host company. In this case, they give the work

area to the different teams and each team will be responsible for developing solutions to

identify problems, and preparing a plan to improve the work area. The number of each team

is varied depending on how big is work area, but each teach team runs for two to four days

and focuses on a process at a host company. Since the limitation of number of needed people

and enough time, this study mainly focuses on a general approach to the manufacturing area

and gives the practical ways to deploy lean concept in manufacturing organization.

Meanwhile, we must be aware that workplace organization is only one element of lean

production and, like the other elements; it alone will not produce huge benefits or be self-

sustaining.



Methodology: The book is an explanatory study helping from quantitative and qualitative

methods that include three different knowledge purposes: explorative, diagnostic, and

normative. A huge amount of collecting data and analyses methods are used to find problems

and solutions. Expert knowledge and historical experiences are highly appreciated in this

study as well. Graphical tools and histograms are vastly used to get an illustrated figure of problems in order to find concrete solution especially in visual point of views.

Summary & Reflections: The book is divided to three main sections. First section includes

primary section with introduction issues such as background, problem, objectives,

delimitation, and approach. Second part is body section that explains main issues of research

and includes methods, analysis, execution, and results. In this section, methods and

techniques of following four major contents must be considered: 1) Problems found, 2) Detail

problems 3) Solutions and results 4) Suggestion. And final section includes discussion,

conclusion, references, and appendices.



Contents:Section one:

Chapter one: Introduction

Section Two: Methods, Analysis, Execution, Results

Chapter two: Work Area Improvement and KAIZEN Techniques

Chapter three: Process Analysis

Chapter four: Motion Study

Chapter five: Time Study

Chapter six: Ratio-Delay Study

Chapter seven: Multiple-Activity Analysis

Chapter eight: Designing an Assembly Process and Balancing

Chapter nine: work Sampling and its Application

Chapter ten: Standard Time Measurement Procedure

Chapter eleven: Setup Within 10 Minutes

Chapter twelve: Design a U-Shaped Line

Chapter thirteen: Implementation of the JIT Production system

Section three:

Discussion

Conclusion



Section one:Chapter One: Introduction

1.1. Background

Nowadays, lean production and lean concept have become hot topic among manufacturing

and service companies, especially after financial crisis rose up at the beginning of 2008. It is

absorbed as a management philosophy by many manufacturers especially within average and

small companies. Many factories in all over the world have used it with different names, in

variety levels with different tools. For example, we can name some successful companies as

pioneer companies such as Scania, Toyota, Nokia, Lockheed Martin, Hewlett Packard, Dell

and Pratt & Whitney. The hopeful point is that the techniques and concept are deployed in

lean processes are not complicated and learning lean among all levels of basic workers with

primary educational background to high management areas will be simply possible.

However, the negative point is that within many applicants the rate of effectiveness of this

approach has not been high. Based on Technology Evaluation Centers, the rate of success of

this philosophy is not more than 20% and 50% of American companies have reported to

execution and implementation, but less than 10% out of them have had a successful result.

The main point must be considered in this regard is that the lean concept must be agreed

among high management level as a concrete solution before starting to implement and

execute it. Another problem is lack of strategy in execution and exploitation in lean

production.

Lean production looks like a depth journey to different layers of manufacturing areas from

first point raw material arrivals to final step storage products to deliver to the customer. The

main goal of this journey is to identify the problems and causes, wastes in material, time,

process, and operation. Although, this journey could be helpless, time consuming, extra cost

unlike we deploy an applied strategy and get reinforced with a road map. We need both

simultaneously in order to understand and to be understood lean team member what to use,

where to use, chasing value stream and mapping it.

1.2. Problem

Majority of production companies’ problem is related to a huge amount of inventory and low

effectiveness among work shop that ends up to increasing the expenditures and the cost of

production. It becomes a crucial problem when some other factors such as increasing

competency of competitors leads the company to an irreversible point in many cases.

Meanwhile, mega driving forces to change the traditional thinking and management that

coming from outside such as recent financial crisis have been caused this change. Some

managers think they can improve manufacturing competitiveness by working harder at thesame methods they have used for decades. Everybody has heard about lean production, but



some managers believe that it is not for them. In fact, they could not identify problems by

traditional methods.

The sources of wastes keep unveiled and myth of large-batch production is not changed due

to fear of shortage of product for delivering to the next customer. This trend also leads to high

rate of defects and consequently increasing cost of production too. Lack of flexibility is

another side effect of using mass production and becoming more sensible by changing line to

the new product ordered by market. All those trends will eventually lead to produce a low

quality product.

1.3. Objective

The goal of the book is finding the current problems and their coming reasons that why they

appear constantly via Lean Production concept. This goal will be achieved by following the

process and gathering data from the work area from the ordering point to the end point. Thebook will suggest solutions how to organize factory’s manufacturing systems and storage

area. In fact, the book will be working on implementation of Lean Production in the work

area in order to get the best possible products is delivered in the shortest possible time at

attractive price. Finally, current situation of the company and final proposals of improvement

in work area will be discussed at the end of the project. Object of the book should be end up

with feasible and practical improvement of factory.

By using the conclusions in the book, we will learn how to identify current and emerging

problems, how to understand the, and how to make solutions concerning the root of a

problem.

1.4. Delimitations

The book gives an explanatory designed plan ready to implement in most manufacturing

areas. Naturally enough, the methods and techniques mentioned must be customized and

regionalized based on cultural and social issues of each company. Also, obviously, this is

student-focused study with limitation in accessibility to the types of resources and technical

issues, and texture of the company. So, it might be different as view point of other person

with different background and availability of sources. So, this matter must be discusses fordifferent perspectives. Finally, as far as went through the project I found it difficult to gather

all data necessary and I changed the scope of the project in a way that giving a complete

structure including methods, tools, samples and templates in facilitate the concrete approach

for future implementation.

1.5. Approach

The base of each lean implementation is designing a strategy and road map to follow. The

sample of this structure is mentioned in chapter called ―Implementation of the JIT ProductionSystem‖ is mentioned. After, as other approaches in practical improvement in factories in



lean production it starts with a general look at the workplace to get a picture of current state

of workshop. It could be followed by implementation of 5Ss at primary phases of execution.

Types of Muda will be discussed later.

Within the usage of quantitative methods we gather the data to analyze processes in order to

get an overview of entire process and details of work flow by using some tools such as OPC

(Operational Process Chart). Motion study, time measurement, ratio-delay study are other

tools to be used for all activities regarding data collection, analysis, problem finding, solution

developing, and process re-organization.

Section Two



Methods, Analysis, Execution, Results Chapter Two: Work Area Improvement

And KAIZEN TechniquesThis chapter shows how to proceed with the workplace improvement. The workplace

improvement begins with the observation of inside the plant. The initial observation,

however, needs to be preceded by clear and well organized understanding of the entire plant

profile.

To get a good picture of the plant profile, what products are manufactured as well as the flow

of processes involved in the manufacture of products need to be investigated. Here, at below

figure, the methods of improvement of workplace are illustrated as follows:

2.1. How to look at the workplace



The following section describes the way to locate problems at the workplace prior to data

collection:

2.1.1. How well the 4S housekeeping is practiced: 4S stands for Seiri (to clear the

workplace of unnecessary things), Seitan (to keep things in order), Seiketsu (to keep

clean) and Seisa (to clean the workplace). In short, it means the workplace is kept neat

and tidy at any time and things are readily accessible and usable when needed. Usually

"Shitsuke" (discipline) is added to above to run a 58 housekeeping campaign as part of

workplace improvement activity.

2.1.2. How well the Visual Control is practiced: Visual control practice means a

methodology has been adopted to allow anybody to see if things are normal or abnormal at a

glance. It means to develop a mechanism which leads to immediate recognition of things going

abnormal or problems being developed.

Let’s consider an example of visual control for keeping things in certain places. Suppose it was

decided to demarcate a section in the workplace by white lines to permit a predetermined

quantity of things to be kept there. Things may be kept inside the demarcation, but if somebody

needs to count the number of objects kept there each time to confirm compliance, the

predetermined quantity is not readily controllable. Therefore, this is not a good example of

"visual control". The same control may be transformed into a visual control by using a "Kanban"

board or a red line system to allow for immediate control when the quantity of stock or works-in-

process exceeds a right quantity.

Some of the examples of visual control are:

A gibbeted head method (Defectives)

A patrol light method which turns on when the machine breaks down

A tool storage board method with tool shapes marked on the board

A double bin system or a 2-bin system for preventing stock-out

Demarcation by white lines

Andon (electric board) system

Posting of standard work instruction sheets

A red line system (Inventory control)

Color coding for indicating an acceptable operating range of an instrument Inventory tag (inventory)

Work-in-process box, etc.

2.1.3. Is data available? Putting aside a casual visit to the workplace, there are two

different ways of looking at the workplace; i.e., observation and monitoring. Observation

means to look at things carefully to get a qualitative picture of the situation, while monitoring



means to collect actual data on site quantitatively such as duration, times and volume. It is

important to analyze the workplace from both observation and monitoring aspects. Check to

see if relevant data is available or not before starting to collect data on your own.

The following is a list of examples of items to be observed when looking at the flow of things

through the processes;

1. Process sequence

2. Content of a job at each process and time required to complete the job

3. Lot size

4. Times and duration of downtime

5. Distance and times of transporting

6. Transporting lot size

7. Inspection content, inspection time and inspection frequency

Some examples of items to be observed when looking at the operation

1. Time required for each job element

2. Cycle time

3. Distance to be traveled

4. Worker’s position and distance

5. Work sequence and motion sequence

6. Frequency of use of jigs, fixtures and tools, etc

Work improvement at workplace begins with collecting above data, then analyzing the

situation and identifying the problems. Different techniques are available to meet therequirements of the specific purpose for problem finding.



2.2. Status investigation of the plant

Plant investigation may be conducted through;

1) Production activity analysis which observes and monitors productionactivity on site (analysis of physical transformation systems)

2) Administrative analysis which examines the flow of office work and/or

how administrative duties are run (analysis of information systems)

The 3-Gen principle of investigation;

1) In real life (Genjitsu)

2) On site (Genba)

3) With actual objects on hand (Genbutsu)

2.2.1. Production activity analysis: This refers to an analysis involving investigation

of how work is done to identify problems and eventually to materialize process

improvement, work improvement or work standardization. The main analysis

technique employed for production activity analysis is IE techniques.

IE techniques include:

1) Serial analysis which analyze the entire plant operation or work flow or

distribution at workplaces

2) Individual analysis which analyzes the content of each job

The techniques may also be classified into:

1) Work measurement which measures work in terms of time

2) Method analysis which observes work sequence and/or methods

Please find the following the representative analysis techniques.



(1) Serial Analysis

Method Overview

Process Analysis

Is a technique which analyzes the production process from materials to

finished products along with the flow of goods and people in order to findand correct problems? Analysis techniques include OPC (Operation Process

Chart), FPC (Flow Process Chart), FD (Flow Diagram), and ST (String

Diagram).

Ratio-delay Study

Is a technique which monitors the content of a job done by entire workplace,

or by worker or machine, in order to analyze the non-production type

elements out of time spent for each work or work sequence for eventual

improvement? The technique includes WS (Work Sampling = Snap Reading)

and Continuous Reading.

Path Analysis

Is a technique which is used to observe the movement of things in the process, and

then analyze the paths for layout improvement, etc?

The technique includes From-To-Chart and Frequency Analysis.

Time Measurement

Is a technique which divides a repetitive work (cycle work) into element jobs,

and then take time readings for each element job, in order to analyze and

subsequently improve variance and magnitude of time readings and work

sequence. The technique includes a Time Study technique.

(2) Individual Analysis

Method Overview

Right & Left Hand

Work Analysis

Is a technique which analyzes for improvement the sequence and roles of

right and left hands of a worker (sometimes including right and left legs),

using process symbols, with due consideration to the relationship between

the two hands. This is an analysis technique which employs process

symbols.

Minor Motion

Analysis

Is a technique which divides a person's motion into basic motions

(therblig) to analyze and improve motions at work? This is a technique

used when more detailed analysis than Right and Left Hand Analysis is

required. This analysis employs therblig symbols.



(3) Applied Analysis using Serial Analysis and Individual Analysis

Method Technique

Man-machine analysis

Is a technique which analyzes and improves a work to be done by man

using machines, or a work to be executed by more than one man jointly

in a team, with a view to minimizing worker waiting or machine non-

operating as far as possible for maximum efficiency?

Line Balance analysisIs a technique for analyzing and improving variance in time allocated to

the job in each process of, mainly, the conveyor line assembling work?

U-shaped line design

analysis

Is a technique used to design an improvement in realizing the

continuous flow production system mainly for machining jobs?

Design of standard timeIs a technique to set a cycle working time and allowance required under

the ideal condition for a job?

2.2.2. Administrative Analysis: Representative Administrative Analysis techniques

include the following:

(1) Office Work Analysis

We need to know whether a technique for investigating the current status of office work

based on hearings, slips and forms, to be followed by analysis of the sequence of

office work process, objectives of work time required, etc. in order to subsequently

improve office work or the extent of computer utilization.

(2) Office Function Analysis

We must be assured whether a method use to describe the job allocation for different

departments and the relationship between different functions or the relationship

between the forms and the objectives of office functions in a job relation analysis or

in a functional information analysis in an effort to analyze and correct duplication,

missing and/or excess of functions.



2.3. Ideas for work improvement

The following shows the established methods for examining ways for work

improvement. These items are followed in asking questions to oneself when

examining the given situation for each work or process.

a. 5W1H method

WHY: Why is it done? Purpose (result, reason)

WHO: Does he have to do that? Man (worker)

WHAT: Does it have to be used? Object (material, machine, and tool)

WHERE: Does it have to be done there? Place (position, path)

WHEN: Does it have to be done then? Time (hour, time, timing)

HOW: Does it have to be done that way? Method (procedure)

b. ECRS of Improvement

Eliminate Wouldn't it be possible to eliminate the process?

Combine Wouldn't it be possible to combine the process with another process?

Rearrange Wouldn't it be possible to rearrange the process with another process?

Simplify Wouldn't it be possible to simplify the work?

In applying the ECRS of improvement, make sure to examine its possible application in the

order of E, C, Rand S.

c. Muri (unreasonable), Muda (waste) and Mura (uneven)

Muri: Trying to do what is not possible to be done

Mura: Workmanship is varied. Sometime it takes more time, and in other times it

takes less time. Some products are good and others are defective. Sometimes it is busy

and in other times it is not busy.

Muda: Doing what does not have to be done.



2.4. Procedure for Workplace Improvement



Chapter Three: Process Analysis

3.1. Role of process analysis

Process analysis is done to improve efficiency of management activities. Management

activities here are measured specifically in terms of flow (movement) of money, things,

people, equipment and information, etc. Process Analysis is carried out to get an idea of flow

(movement) of things, people and information over time, then to see if there is any problem

to be corrected and subsequently to create a more efficient flow (movement) of things, people

and information.

3.2. Process analysis methodology

Process Analysis uses an analysis chart to record, analyze and then examine the flow

(movement) of things, people and information over time using analysis symbols.

3.3. Process phenomena and analysis symbols

3.3.1. Process/ operation ----------------------

When the physical or chemical property of an object of analysis is

intentionally transformed.

When an object of analysis is assembled or disassembled.

Refers to a state of value added activity, such as when planning or

calculation is done.

3.3.2. Transport loaded/Movement ----------

Refers to a state where an object of analysis is moved (moves) from one

place to another.

3.3.3. Inspection -----------------------------------

When difference between an object of analysis and the standard is

examined.

Refers to a state where quality or quantity of any one of various properties

of an object of analysis is confirmed.3.3.4. Standstill/Delay ---------------D

Refers to a stationary state where a phase planned for an object of analysis

cannot be implemented or is not needed. This does not include, however,

the situation when an object of analysis is left stationary for the purpose of

physical or chemical transformation.

3.3.5. Storage ----------- --------------

Refers to a state where an object of analysis is kept stationary in a manner

that it may not be moved without due procedure or authorization.

Note: Processing/Operation represents a value added phenomenon, whileTransport/Movement, Inspection and Standstill/Delay represent cost raising phenomena.



3.4. Types of process analysis

Material - type Process Analysis: Analyzes a flow (movement) of things over time.

Man-type Process Analysis: Analyzes movement of a worker over time.

Office Process Analysis: Analyzes a flow of information over time.

3.5. Process analysis charts

Operation Process Chart (our/we process analysis chart)

Is a chart which describes the sequence and relationship among processing/work and

inspection selectively extracted out of the flow of an object of analysis over time?

* This chart is used:

To get a picture of entire process prior to detailed analysis, To find the important points for work study purpose,

To serve as basic information for layout examination (overall),

To prevent discussion points from being unfocused as well as to ensure the

association with others should not be missed at various discussions concerning

the production process.

Flow Process Chart (detailed process analysis chart)

Is a chart which describes the sequence and relationship among all the process

phenomena for an object of analysis (processing/operation, transporting/movement,

inspection, standstill/delay and storage) using symbols, and also add information

needed for analysis purpose such as required time, distance of travel, quantity, etc.

* This chart is suited in particular for:

Material handling (re-handling phenomenon)

Plant layout (equipment location)

Standstill, waiting time

Storage time.

Note: A clerical process chart is generally used for office process analysis. This chart

is basically structured as in a flow process chart.

Flow Diagram

Generally, a rough layout diagram is prepared for the buildings, machines and work

areas at a scale of 1/100 or 1/50, and the flow (movement) of an object of analysis

over time is described on this layout using process analysis symbols.

*This chart visually presents:

Congested flows (movements)

Unnecessary walk or transporting



Locations where heavy traffic of people or things occurs, and, therefore, is used

when improving the layout.

Note: String Diagram is prepared for the same purpose as Flow Diagram. This chart

describes the flow (movement) of an object of analysis in strings and is used for

rough review.



Fig.3.1. Example of OPC:

Product name: Product No: Research data: Authorized by:

Process: charging production No.: Prepared on: Prepared by:

Label Gas Undiluted solution Can

Source: “ Seven tools for Industrial Engineering” , Practical Management Research Group,

PHP

1-7 Acceptance

inspection1-4 Acceptance

inspection1-2 Acceptance

inspection

Acceptance

inspection1-1

1-10 Additive

0-3

1-3

Make contents

Semi-finished

Product inspection

0-1

0-2

Line setting

Elimination of extraneous

materials0-4 Charge can

Valve

0-5 Fit valve

0-6

1-5

0-7

1-6 Spout cap

0-8

Charge with gas

Check for leaks

Stamp number

on can

Weight check

Fit cap

0-9

1-8

Printing

Product

0-10 Stick label on

1-9 Final inspection12 pack

0-11

0-12

0-13

Make up

Package incarton

Load onto pallet



Fig. 3.2. Example of FPC:

Source: "Seven Tools for Industrial Engineering", Practical Management Research Group,

PHP



Fig. 3.3. Example of Flow Diagram:

Work name: Material acceptance inspection

Prepared by: Scale: 1/100 (m)

Source: "Seven Tools for Industrial Engineering", Practical Management Research Group, PHP

1.2

Current methodNew method

Wall (east)

Instruments

Inspector

office

Unpacking yard

Shoot

DoorWork bench Work bench

6.0

5.0

1.0 Scrap bin

9.1

1.0

Shelf

Shelf

Shelf

Acceptance

bench 1.0

4.6

1.015.2

1.0

Inspection bench

1.01.0

9.1

Truck

Partition

Chart No: ..............................

Plant: ....................................

Date: .....................................

Wall

(north)

Storage shelfWall (west)

Parts

Storage shelf

Inspection seal

bench

Wall

(South)



Examples of String Diagram:

Current Situation

A warehouse person travels as much as 260 meters to pick parts for assembling. The congested

pattern of strings illustrates complicated movements of the warehouse person.

After improvement

Under the new layout, the warehouse person travels only77 meters to pick the same parts.



3.6. Analysis and review of charts

Proceed with analysis and examination without any prejudice or preconception

Putting particulars aside, start with the analysis and review of overall flow(movement)

Check if there is any problem with 5W1 H questions

a. What is the objective? - - - Get rid of unnecessary jobs.

b. Where should it be done? - - - Change the place, or keep it the same.

c. When should it be done? - - - Change the time or sequence, or do it at once.

d. Who should do it? - - - Change the worker, or keep the same worker.

e. How should it be done? - - - Simplify the method, or improve the method.

Use the checklist for a clue in improving the flow (movement)

a. Wouldn't it be possible to reorganize (changing the sequence) or combine the work to

minimize losses?

b. Wouldn't it be possible to eliminate some of the current workload by using new materials

or new methods?

c. Wouldn't it be possible to eliminate the posterior work by improving jigs or fixtures?

d. Wouldn't it be possible to reduce or eliminate work-in-process through continuous

operation?

e. Is the number of control points (inspection) kept to a minimum level, or is it kept at the

most appropriate level? f. Wouldn't it be possible to change to a flow with more sophisticated

automation?

Use the checklist for a clue in improving work

a. Does the work accomplish the expected result?

b. Wouldn't it be possible to eliminate the work by improving or changing the preceding

work?

c. Wouldn't it be possible to simplify the subsequent operation by enriching the work in

question?

d. Does the practice more economical in comparison with that of the

contractor or the competitor?



Chapter Four: Motion Study

This chapter studies on motion of human body mainly on hands movement considering time

and movement measurements in order to increase the motion economy of human body. It willemphasize on some principles that must be considered during studying on motion of body.

4.1. Principles of motion economy: (Principles

concerning human body)

4.1.1. Motion with both hands should begin with both hands together and end with

both hands together.

4.1.2. Left and right hands should not left idle together at any time other than break

time.

4.1.3. Left and right hands should, be used in opposite directions symmetrically at

once. This principle is closely related and should be put into perspective in

parallel. Two hands can obviously accomplish more than one hand. Also it is

more effective to arrange similar jobs on either side of the work station so a left

hand and a right hand move together to do the same motion. Moving arms in

opposite directions held keep a balance, allowing a worker to work under less

psychological and physical load.

4.1.4. Use force of a thing (momentum) as much as possible. When muscle needs to

overcome this force, keep the momentum to a minimum. Force of a thing means

weight of a material to be moved, weight of a tool or equipment to be moved,

and weight of body parts to be moved. In many instances, use of such

momentum allows for efficient execution of work.

4.1.5. Hand motions should be limited to the minimum categories which enable

satisfactory execution of work:

a) Finger motion

b) Motion including fingers and wrists

c) Motion including fingers, wrists and forearms

d) Motion including fingers, wrists, forearms and upper arms

e) Motion including fingers, wrists, forearms, upper arms and shoulders

At the phase e), one needs to move out of the upright posture.



4.1.6. A continued, smooth motion is preferred over a zigzag motion or sudden

change in directions. Sudden changes in directions not only waste time but also

exhaust a worker.

4.1.7. A parabolic movement allows for a faster, easier and more accurate motion

than a restricted motion. In parabolic movement, muscle contracts when

movement begins and then subsequently stays relaxed, allowing for less fatigue,

more force and faster and accurate motion.

4.1.8. Keep the rhythms in doing the work as much as possible. A proper sequence

of motions provides for rhythmic operations for a worker to keep on going with

less effort and less fatigue.

4.2. Layout within the work area4.2.1. Keep all the tools and materials in predetermined locations. Tools and

materials must always be kept at the same places so a worker can easily locate

them. Keeping things affixed locations helps a worker to develop a habit and do

the motions quickly and unconsciously.

4.2.2. Keep tools, materials and control equipment close to a worker and facing the

worker. When work is to be done on the work bench or on the machine, tools

and materials necessary for the work should be laid out within an area as

illustrated in the following diagram.

4.2.3. Use a gravity effect for a container when sending materials to the place where

they are to be used. An angled bottom of a container sends materialsautomatically to the front section where a worker can reach by hands, thus

eliminating the need for him to reach out to the further section of the container.

4.2.4. Use the gravity feed as far as possible. A worker releases a finished work

piece as it is finished on site so the work piece will roll off to the predetermined

location by gravity, thus the rhythm of operation is not interrupted and he can

proceed to the next work piece right away.

4.2.5. Lay out materials and tools in a way that assures the best sequence of motions.

The materials necessary for the work must be kept closest to the point where the

finished work piece is released. This helps eliminate wasteful motions.

4.2.6. Give thought to the proper level of illumination. It should not be too bright nor

too dark. Proper level of illumination must satisfy the following three conditions:

a. Intensity of illumination is sufficient for the work

b. With appropriate color and no glare

c. Lights come from right directions

4.2.7. Set the height of the work surface and chair to the level which allows for easy

working condition either standing or sitting.

4.2.8. Provide each worker with a chair of right shape and height which allows him

to take a right posture.



Fig.1 illustrates the maximum range

reachable by a worker with his left hand

and right hand fully extended.

1 ) Horizontal direction

To reach beyond this range, he needs to

move his shoulders. The range shown in

broken line gives a range where a

worker can do the work using his left

and right hands with elbows as fulcrum.

Within the shaded range in Fig. 2, a

worker can easily grasp a small object.

Within the shaded range in Fig. 3, a

worker can move both bands together

symmetrically without associated eye

movements.

2) Vertical direction

Fig.4 illustrates the maximum range

reachanle vertically with hands fully

extended and a working range with

elbows as fulcrum.

4.3. Design of tools and equipment 4.3.1. Use a foot as much as practical. Use of foot allows for both hands to do other

motions.

4.3.2. Combine tools as much as possible. An efficient tool should have both ends

usable. (Ex. A hammer and pincers, a pencil with eraser, etc.)

4.3.3. Keep tools and materials on hand in advance as far as possible. It is important

to keep them at predetermined locations so they may be easily accessible when

needed.

4.3.4. Keep cranks and handles in a manner so the widest surface area may come in

contact with the palm.

4.3.5. Design must consider that a worker should be able to operate the machine

without bending his knees.



4.4. Checklist for basic motions4.4.1. Reach

Is a motion of reaching by hands necessary at this point of the entire work cycle?

If it is necessary, would it be possible to shorten the distance to reach? Wouldn't it be possible to improve the layout of the present work station and reduce

the reaching motions?

Wouldn't it possible to reduce the frequency of reaching by hands by using other

methods, for instance, by transporting more than one object at a time?

Wouldn't it be possible to shorten the reaching distance by using a hopper and a

shoot?

Wouldn't it be possible to redesign the machine operation and shorten the reaching

distance?

Wouldn't it be possible to shorten the reaching distance by clearly defining the

locations to keep the tools in a more convenient layout?

Wouldn't it be possible to reduce reaching motions by keeping already processed

materials and unprocessed materials closer?

Wouldn't it be possible to combine the motion of releasing the work piece with the

motion of grasping the next work piece and omit a reaching motion?

Wouldn't it be possible to combine this motion with the preceding and/or subsequent

motions? Further, wouldn't it be possible to omit a reaching motion all together?

4.4.2. Transport loaded

Is this motion necessary?

If it is necessary, would it be possible to shorten the distance?

Wouldn't it be possible to improve the layout of the present work station and reduce

the transporting motions?

Wouldn't it possible to reduce the frequency of transporting by transporting more than

1 object at a time?

Wouldn't it be possible to reduce or omit transporting motions by using a shoot or a

conveyor?

Wouldn't it be possible to eliminate resistance caused when operating the machine by

attaching a spring or weight, or by improving the design?

Wouldn't it be possible to eliminate resistance by hanging the hand tools with springor by attaching a balancer?

Wouldn't it be possible to change the transporting motion by devising a system to

push and move the finished materials to the next work station?

Wouldn't it be possible to eliminate the transporting motion by sending off the work

piece to the next work station by gravity?


motions? Further, wouldn't it be possible to omit the reaching motion all together?



4.4.3. Direction changes

Wouldn't it be possible to omit the motion of changing directions by reviewing the

position of keeping materials?

Isn't it true that a motion of changing directions is needed due to the design of a

machine or fixed equipment? Wouldn't it be possible to omit a motion of changing directions by keeping all the

materials and tools at the level equal to the work plane?

Are there any instances where a worker chooses to omit a motion of changing

directions on his own judgment as he is not fully informed of the meaning of

changing directions?

Isn't it the case that the very design of a material container is causing changes of

directions necessary?

4.4.4. Grasp

Is a grasping motion necessary at this point of the work cycle? If it is necessary, would it be possible to improve the method used for the grasping

motion?

Wouldn't it be possible to replace a pick-and-grasp motion with a slide-and-grasp

motion?

Wouldn't it be possible to redesign for easier grasping of a work piece?

Isn't it true that when a reaching motion is connected with the subsequent transporting

motion in a continuum, the grasping motion in between may be executed without

losing time?

Are the machine operation board and tools designed in such a way that an operator

can grasp them without looking at them?

Wouldn't it be possible to simplify the grasping motion by adopting a hopper feed

which always feeds work pieces to the same position?

Wouldn't it be possible to shorten the time required to grasp very small work pieces

by placing them on the soft and resilient surface?


motions? Wouldn't it then be possible to omit the grasping motion?

4.4.5. Hold

Wouldn't it be possible to omit the holding motion by using a vice, jig, tool or fixture?

If that is possible, is there any other work that may be done by a hand which has been

freed?

Wouldn't it be possible that omitting of the holding motion enable left and right hands

to do other motions?

Wouldn't it be possible to transform a holding motion to a more productive work?

Does that work piece have to be held at all?



4.4.6. Release load

Wouldn't it be possible to drop the work piece to fall while reaching for the next

material?

Wouldn't it be possible to release the work piece in one hand while grasping the next

work piece with another hand? Wouldn't it be possible for a worker to keep the frequently used tool in his hand all

the time?

Wouldn't it be possible to improve the motion so a work piece which tends to stick to

fingers can be released quickly?

Wouldn't it be possible to combine a certain motion with the preceding and/or

subsequent motions in order to omit the releasing load motion?

4.4.7. Pre-positioning

Is that pre-positioning indispensable for the subsequent motion?

Wouldn't it be possible to omit the pre-positioning motion by aligning materials in amore efficient manner?

Wouldn't it be possible to omit the pre-positioning motion by using a hopper feed?

Wouldn't it be possible to place the work piece in a manner which precludes the need

by the next worker for a pre-positioning motion?

Wouldn't it be possible to omit the pre-positioning motion by changing the design of

parts involved? 4.4.8. Part

Wouldn't it be possible to omit the parting motion by changing the parts design or

assembling methods? Wouldn't it be possible to replace this motion with another?

4.4.9. Positioning

Wouldn't it be possible to omit the positioning motion by use of a stopper or a guide?

Wouldn't it be possible to omit the positioning motion by changing the mold design?

Wouldn't it be possible to attach a guide for shortening the time required for the

screwdriver positioning?

Wouldn't it be possible to omit the positioning motion by changing the design of

pliers?

Wouldn't it be possible to chamfer the edges of a work piece or make openings inorder to facilitate positioning when assembling?

Wouldn't it be possible to reduce the delicate motions including positioning by

installing a funnel shape receptor or a holder?

4.4.10. Plan

Wouldn't it be possible to omit the planning motion by a proper instruction from a

supervisor?

If a planning motion arises every time a work is repeated, isn't it so because

standardization is lacking?



Is the worker in question a competent worker who can do the work without thinking

hard?

4.4.11. Search and select

Wouldn't it be possible to omit this motion by pre-positioning the work pieces?

Is there anything other than necessary tools and materials left in the working area? Wouldn't it be possible to omit the motion by changing the design of the work piece

to a symmetrical shape?

Is a work piece standardized to eliminate the need for selecting?

Wouldn't it be possible to give a worker a proper instruction in order to induce him to

be conscious of the motion before doing the actual searching or selecting motion so he

can proceed without hesitation?

4.4.12. Inspect

Is the inspecting motion necessary for executing the work satisfactorily?

Wouldn't it be possible to omit the inspecting motion by improving the precedingwork?

Wouldn't it be possible to connect the inspecting motion with other motions such as a

transporting motion?

If the visual inspection is required, wouldn't it be possible to improve other motions in

order to reduce eye fatigue?

4.4.13. Avoidable delay

Isn't it necessary to take some actions in order to prevent avoidable delay from

happening too often?

Wouldn't it be possible to reduce the instances of avoidable delays with clearinstructions or with strict supervision?

If there are many instances of avoidable delays, wouldn't it be possible to introduce

the incentive scheme to reduce them?

4.4.14. Unavoidable delays

When an unavoidable delay is caused, wouldn't it be possible to transfer part of the

job from a hand which a worker can use with greater skill and ease to another hand

which he uses with less skill and ease?

Wouldn't it be possible to have the motion done by both hands?

If it turns out as a result of investigation that the motion can be done best by one hand,

wouldn't it be possible to use a one-handed person?

When a worker has no choice but to be engaged in a one-handed motion, isn't it likely

that another hand is exposed to a danger?

If unavoidable delays cannot be omitted from the work cycle, wouldn't it be possible

to leave them in the hands of unskilled workers?

4.4.15. Balance delay

Wouldn't it be possible to eliminate the balance delays by changing the work area

layout?



Wouldn't it be possible to give a job to a hand which is left idle due to a balance

delay?

Wouldn't it be possible to change the work piece design in order to eliminate balance

delays?

If balance delays are caused due to a wrong position at which machines are operated,wouldn't be possible to re-layout the machines?



Table 4.1. Therblig symbols:

No Therblig

Name

Therblig symbols Example

letter Symbol Description

1 Search SH

A shape representing an eye

searching for an object

Searching for a

pencil

2 Select ST A shape of pointing to the object

selected

Selecting a pencil

out of several

3 Grasp G

A shape of a hand grasping an

object

Grasping a pencil

4 Transport Empty TE

A shape of empty hand Reaching for a

pencil

5 Transport loaded TL A shape of a hand holding an

object

Fetching a pencil

6 Hold H A shape of a magnet attracting

an object

Holding a pencil

7 Release load RL

A shape of keeping an object at

finger up

Placing a pencil

8 Positioning P

A shape of flipping an object at

finger tip

Pacing a tip of a

pencil on the specific

position

9 Prepositioning PP

Balling pins Re- holding a pencil

so it is easier to use

10 Inspect I

A shape of a lens Inspection the

handwriting

11 Assemble A

A shape Fitting a cap on the

pencil

12 Disassemble DA A shape less one bar Removing a cap

13 Use U U for use Writing

14 Unavoidable Delay UD

A figure of a person stumbling

down

Writing as one

cannot write due to

power outage

15 Avoidable Delay AD

A figure of a person lying Is looking away and

not writing

16 Plan PN

A figure of a person planning

with his hand on his head

Planning for what to

write

17 Rest for overcoming

fatigue

R

A figure of a person resting

seated on a chair

Take a rest as he gets

tired



4.5. Principles of motion economy: (Gist for

judging check items)

Those in compliance with the principles of motion economy are listed on the left side of the judgment column.

4.5.1. Use of a body

4.5.1.1. Range of body parts used: A body motion can be accomplished at a

shorter time when executed within the minimum possible range of body use

to do a given job satisfactorily. The range of motion classification may be

divided into 5 stages. Requirement for time and labor increases according

to these stages.

Small: a. Finger motions

b. Motions including finger, wrists and forearms

c. Motions including finger, wrists, forearms and upper arms

Large: d. Motions including finger, wrists, forearms, upper arms and

shoulders

4.5.1.2. Simultaneity of left and right hands motion: Motions with left and

right hands should be started simultaneously and ended simultaneously.

Both hands should not be left idle simultaneously at any time other than

rest time.

4.5.1.3. Symmetry of left and right hands motion: This principle is closelyrelated to 5.1.2 and should be considered along with 5.1.2. Two hands can

obviously accomplish a job more effectively than one hand. Also when the

right and left hands move together with either arm moved in opposite

directions, a worker can keep a good balance, allowing him to work with

less effort.

4.5.1.4. Motions using inertia and gravity (momentum): Use the force of a

moving object (momentum) as much as possible, as it is less tiring. When

work needs to be done against the momentum, keep the momentum to a

minimum. Momentum means weight of a material, a tool or body parts tobe moved. Leveraging on such momentum allows for more efficient

execution of work.

4.5.1.5. Use of parabolic motions: A parabolic (trajectory of a parabola as

drawn when an object is thrown into the air) movement is less tiring, faster

and more accurate in doing the work. It is easier to do than doing the

restricted motion.

4.5.1.6. Continuity of motions: A continued, smooth motion is better than a

zigzag motion or a motion which requires sudden changes in directions.



4.5.1.7. Motions requiring intensive focusing and care: A job requiring

focusing attention on an object often takes long to accomplish. As a worker

cannot attend to other jobs during that time, work efficiency is low.

4.5.1.8. Rhythmic motions: A proper sequence of motions provides for

rhythmic operations for a worker to keep on going with less fatigue4.5.1.9. Hazardous work: Hazardous work takes extra attention other than

concentration required for the job, and results in poor work efficiency.

4.5.2. Layout of the Work Area

4.5.2.1. Fixed location for tools and materials: If tools and materials are kept at

the fixed locations, a worker will develop a habit for reaching to them

without searching, and can get to the work expeditiously.

4.5.2.2. Size of a work area: One to two steps of walk may well be needed to

do the work within an assigned work area, but the work area which requires

more than several steps of walk is too large as extra time spent for moving

along results in poor work efficiency.

4.5.2.3. Leveraging on gravity for feeding: It is desirable to have work pieces

fed in front of a worker automatically by their own weight so all he has to

do is to reach for and pick them up. Try to eliminate a motion for the

worker to reach far for the materials on the opposite side of the container.

4.5.2.4. Frontal layout of tools and materials: Tools and materials necessary for

doing the work should be kept in front of a worker so he does not have to

bend or turn himself around to reach for them.

4.5.2.5. Sequential layout of tools and materials: Work efficiency improves

when tools and materials necessary for the work are kept in the order of use.

4.5.2.6. Brightness of illumination: Illumination should not be too bright nor

too dark. Proper level of illumination suitable for the given workplace

should be used to reduce eye fatigue.

4.5.2.7. Work efficiency by height of work bench and chairs: Set the height of

the work surface and chair to the level which allows for easy working

condition both standing and sitting. A chair to be seated shallow rather than

deeply proves more efficiency for a working chair.

4.5.2.8. Working posture of a worker: A worker will develop fatigue easilywhen working with a forward bending posture or throwing himself

backward. Work efficiency also suffers.

4.5.3. Design of tools and equipment

4.5.3.1. Percentage of manual work in cycle work: Divide the working hours

into manual working hours and machining hours and see if either one

occupies more than half of total working hours. If manual working hours

have a large proportion, work improvement is called for, while if

machining hours have a larger proportion (manual working hours are less),

the number of machines per worker needs to be reexamined.

4.5.3.2. Use of body parts other than hands: There are many instances where

body parts other than hands such as foot, torso or hips may be used to do



the work. To make use of these body parts, hands should be used

exclusively for the type of jobs that may be done only by hands, while jigs

and tools should be devised to allow the use of other body parts as far as

practical.

4.5.3.3. Use of combination tools: Time lost by placing or replacing a tool isoften assignable loss in assembling work. Multiple tools to be used for one

job should be combined into one.

4.5.3.4. Pre-positioning of tools and materials: Pre-positioning means to keep

things at a predetermined place so they may be readily accessible when and

where needed. A waste belt for holding tools worn by an electrician is a

good example.

4.5.3.5. Concentration of operating points: The machines to be operated inside

the work area should be positioned in such a manner that an operator can

reach the switches and levers without walking. The work efficiency will

improve when the machines are placed in one location.

4.5.3.6. Size of the surface area on instruments and tools to contact a hand: A

greater area of contact by hand makes it easier for a worker to exert force

on the crank or a handle with less effort and fatigue.



Table 4.2. Sample of Principle of Motion Economy Checklist: Principle of Motion

Economy :Checklist

Date Checked by Company

Product Process Machine Worker

U S E O F

B O D Y

Check items Judgment

Range of body parts used Small Large

Simultaneity of left & right hand motions simultaneous Different

Symmetry of left & right hand motions Symmetric asymmetric

Motions using inertia and gravity

(momentum)

Yes No

Use of parabolic motions Yes No

Continuity of motions continuous Not continuous

Work requiring close attention and

Care

Few Many

Rhythmic motions Yes no

Hazardous work No Yes

L A Y O U T O F

W O R K A R E A

Fixed location for tools and materials Fixed Varied

Size of work area Small Large

Use of gravity for feeding Yes NoFrontal positioning of tools and materials Yes No

Keeping tools and materials in the order of

use

Orderly Disorderly

Illumination Appropriate Inappropriate

Work efficiency in terms of work bench

chair height

Appropriate Inappropriate

Working posture of a worker Natural unnatural

D E S I G N O F T O O L

S

A N D E Q U I P M E N T

Proportion of manual work in cycle work Large small

Use of body parts other than hands Yes no

Use of combined tools Yes no

Pre- positioning of tools and materials Yes no

Concentration of operating points Yes no

Size of contact surface between

instruments/ tools and hand

Large small

Source: "IE no kiso" Kenpakusha



Chapter Five: Time Study

Time required completing a task (even it is the same) type/amount of task, varies

according to who the worker is and what working method is utilized. Timemeasurement is designed to take hold of and assess me content of operational

requirements and quality of performance by the common gauge for any person

involved in measurement.

Time measurement is used to improve, design and manage operational systems (i.e.,

operational method and job assignment) by assessing a particular task via time scale.

5.1. Goals of time measurement Improve operational system: Monitor work performance cycle, scale of

work element, and extent/order of fluctuation of performance and get a clue

for improvement.

Design operational system: Use time measurement method as the criteria to

compare relative' merits of several methods to achieve a goal, if there are

more than two approaches available.

Manage operational system: Establish standard time required to implement

task and use it as information to plan, guide, control, and evaluate work (and

workers).

5.2. Methodology5.2.1. Direct time measurement method (Stopwatch method): Time study

in a narrow sense, in short, the stopwatch method, is the most

fundamental approach to monitor task performance. Time value being

used in this method is the unit of decimal minutes (DM, 1 DM=0.6

seconds).

Reference: 100 DM=100 x 0.6 sec. = 60 sec. = 1 min.

5.2.2. Predetermined time system (PTS): PTS is a technique to obtain astandard time for the whole work by subdividing a task into elemental

motions, assigning pre-set standard times for motions by unit of nature

and condition of such motions, and summating them.

5.3. Procedure for time study5.3.1. Clarify the objectives:

5.3.1.1. Compare relative merits of more than two tasks

5.3.1.2. Develop a plan to improve productivity

5.3.1.3. Find out products and process whose processing cost is

high relative to their total cost



5.3.1.4. Obtain standard time to alter control system/method

5.3.1.5. Obtain standard time to assess cost of new products/new

approaches

5.3.2. Select tasks to be monitored

5.3.3. Select workers to be monitored5.3.4. Obtain support and cooperation of workers and other people

involved

5.3.5. Review working method:

5.3.5.1. Collect information on task

5.3.5.2. Subdivide a task into work elements

5.3.6. Conduct preliminary research

5.3.7. Determine frequency of monitoring

5.3.8. Implement monitoring

5.3.9. Summarize and analyze result of monitoring

5.4. Subdivide tasks into work elements5.4.1. Reasons for subdivision:

Define details of working methods

Improve working methods by identifying their small changes which occurred

Compare with common elements contained in other tasks and standardize

them

Improve accuracy in rating

Raise level of precision of analysis

Identify tasks which generate severe exhaustion and assign appropriate

working time

5.4.2. Approaches to subdividing task into elemental motions:

Determining the extent of subdivision of tasks for monitoring depends on the

nature of tasks. In general, however, it is useful to subdivide tasks according

to the following principles. Before taking on this step, it is also better to fully

understand a particular task, which will be divided into elements, to the extent

one can epitomize it, in order to obtain acceptable results.

Subdivided elements should: be able to differentiate themselves from other elements

be short enough to be monitored precisely

include only the motions for the same goal

With this method:

time for manual procedure and machine operation time should be clearly

differentiated

invariable elements and variables should be differentiated

work elements which repeatedly occur outside regular cycle operation should

be marked off And,



in case the standard time materials are prepared, consider subdividing

elements in accordance with these materials

5.5. Frequency of monitoringIn a strict term, frequency of monitoring should be determined on the basis of

statistical figures. Normally, however, when the purpose of monitoring is to improve the

operational system, frequency should be between 15 and 20, and between 30 and 40 for

a task of a very short cycle.

When the purpose is to establish a standard or prepare time material, the shorter

the time cycle for work, the more frequent the monitoring should be carried out.

Table 5.1.Benchmark for Monitoring Frequency from Cycle Time

Cycle time

(unit: minute)

Up to

0.10

Up to

0.25

Up to

0.50

Up to

0.75

Up to

1.0

Up to

2.0

Up to

5.0

Up to

10.0

Up to

20.0

Up to

40.0

Over

40

Frequency 200 100 60 40 30 20 15 10 8 5 3

Please see next page! Table 5.2. Example of Time Study (Repetitive Time

Measurement Sheet)



Prepared

by: Seal of

approval

Approved

by: Name :Title of

Operation

Draw letters on a blackboardTitle of task

XXYY Department/ Factory Department : Parts/ product

Work Improvement team

Unit:Blackboard, Chalk, Blackboard eraserTools/ machines

averagetotal15143121110987654321Work elementNo

No

12.0108111214121111131212Get up and walk to

the blackboard

1

99432417611508737M12

5.348576456555Erase the letters on

the board with

blackboard eraser

2

99939754165692427917

23.3210252322242524212422Pick up a chalk and

write down time

study

3

9324629710041932166310339

10.1101101091111910111010Come back to desk

and sit down

4

103472206155230226741349

12.7114131114121214131213Check items in the

checking sheet

5

947832027641639-2562

6

47A

Sharpen pencils

7

63

28B

Beet the blackboard

eraser

8

69

9

Task element

3-93

10

11

12

63.464636563647765496362Total

Note

(processing conditions and others)

Worker

Male,22years oldSex/ Age

XX years YY monthsExperience

Excellent Good fair Acceptable

not good

Level of skills

Level of

lighting

Humidity:

70%

Temperature

19C

Weather:

Cloudy



5.6. Monitoring instructions Take a position where tasks can be observed clearly.

— Stand obliquely behind the worker, or 2 meters away in front of the

worker.

Observer's eyes, stopwatch, and a worker to be observed should be aligned as

a straight line.

Look at a stopwatch and workers /performances alternately during

observation.

5.7. Monitoring sheet and data entry5.7.1. Monitoring Sheet

Time Survey Sheet for Cycle Operation

5.7.2. Followings are additional examples to register irregular items

and other matters in the worksheet.

In case sequence of work elements is changed

In case work elements are omitted

In case monitoring staff overlooked the checking items

In case irregular task occurs

In case abnormal reading is observed

5.8. Examining a result of time study5.7.3. Examine work elements based on average time: Figure out the work

element, which has taken the longest time to perform, by registering

the work elements in order of length of average time spent. The

work element, which would become significantly effective, if

improved, can be identified through this process.

5.7.4. Examine work elements based on fluctuation/variation in time.

There are three types of variation (dispersion) among data (time

readings):

For every observation, different data is obtained (overall

dispersion among individual data)

When several workers perform the same job, averageoperation time differs among them. (between-worker

variation)

Average operation time varies according to the timeframe of

the day (morning, afternoon, or evening), on different days,

perhaps due to physical condition of workers (day-to-day or

between-day variation)

Note 1: Items to be studied when there are fluctuations in time (among data):

(1) Condition of materials, quality of parts, and variation of volume

(2) Performance and maintenance of tools, way of using tools,movement of workers



(3) Maintenance condition of machineries and facilities, precision and

capability of machinery, whether worker possesses professional sense

and "has the hang of the job

(4) Level of skills and technique of workers, tendency to hesitate, tasks

which requires making decisions(5) Location of materials, parts, and tools, the different way of placing

them; and

(6) Environment (temperature, humidity, weather, season)

Note 2: Examining the results based on the principles of kaizen (improvement)

and standardization:

(1) When the conditions are the same, operation time should be

constant in line with the level of skills or extent of efforts of workers

(2) The shortest operation time observed from the skilled worker will

be used as an achievable goal

(3) When workers stop to wonder what to do or sometimes halt the

performance, identify the cause and eliminate them

(4)When waiting is observed, and if it is not to remove fatigue, find a

way to eliminate such waiting and raise performance level



Chapter Six: Ratio-Delay Study

6.1. What is operation?Operation is a condition of workers, who are capable of adding value to their

organization, observed during working hours. In Ratio-delay study, there are

two possible conditions observed.

Operative: Value-added activities (activities)

Working-hour conditions

Non-operative: Cost-generating activities (activities)

6.2. What is ratio-delay study?Ratio-delay study is to monitor the operating conditions of a worker or machinery

per day or over the long period of time and to assume statistically and understand

the time component ratio relative to operational content. The main purpose of this

analytical method is to improve the system to be more productive and find an

appropriate rate of allowance for establishing (revising)standard time, by

analyzing the composition of productive activities (valiant operation=value-added

activities), and non-productive activities (non-valiant operation=cost-generating

activities).

6.3. Objectives of ratio-delay study6.3.1. Essential objective: Ratio-delay study aims at determining whether

the job is worth doing or not, planning valiant work to be engaged in,

and at learning to acquire value-added awareness.

6.3.2. Improve work efficiency and make proper work assignment:

To eliminate the waiting loss for workers and machines and stabilize units

produced

To identify the scale of opportunity interference of each worker and decidethe number of machinery to be assigned to a worker

To plan the complete elimination of cost-generating activities

To improve and standardize the preliminary step of non-repetitive task

To identify variation in the production by hourly or daily duration, and to

improve system to obtain always predetermined production volume

To determine appropriate workforce, facility and operating method

6.3.3. Design standardization of operational process

Preliminary task for establishing output standard

Examine degree of hourly accuracy



6.4. Classification of operationsThe overall classification of operation is defined in the following table.

Classification Description Example of task

o p e r a t i o n

M a i n o p e r a t i o n

E s s e n t i a l Tasks directly related to materials, and

metamorphosis of parts

Cutting process, such as cutting screws or

opening holes, which generates fragments

of powder

I n c i d e n t a l

Factors arising in conjunction with

essential task but only contributing

indirectly to the purpose of tasks.

Installation and removal of parts, measuring

size, operation of machinery (start, halt, and

make transmission, etc.)

S u p p l e m e n t a

l Tasks involving preliminary, procedural,

winding up, and transportation, which occurs

every production lot. (When professional

worker is involved in the task, then the task

becomes his/her essential task)

Task preparation, winding up, & getting

processed goods, jig, fixing materials;

machinery cleaning, updating process

range, disposing the cut-powder, read work

report and technical drawing

A l l o w a n c e

O p e r a t i o n a l

a l l o w a n c e

Though required allowance, operational

allowance occurs irregularly and fortuitously,

often takes place due to the un-standardized

condition of tools, machines, and materials

Oil filling, switch tools, adjust small defects

of materials, cleaning of tools and

machines, tune-up of machines, borrowing

of special tools, replenishing and shipment

of tools

M a n a g e r i a l a n d

e n v i r o n m e n t a l

A l l o w a n c e

Delay due to the waiting loss, managerial

deficiency, not directly related to original

task. Can be reduced by improving managerial

control.

Electric power-failure, accidental machine trouble, loss time from waiting for arrival of

materials, regular morning meeting,

cleaning-up before work, routine errands

before work or reporting process

P e r s o n a l

A l l o w a n c e

Extra time required for human to satisfy

natural demand

Going to bathroom, drinking water, taking

away sweat, warming up in winter-time

F a t i g u e

r e l a t e d

a l l o w a n c e

Extra time and delay due to fatigue from work Taking care of heavy materials, takingbreaks because of severe working condition

Non-

Operational

Factors occurring from private causes or

laziness of worker

Late arrival at work, slow to start work,

finishing task earlier than predetermined,

attending hospital, excessive chatting



6.5. Types of ratio-delay study6.5.1. Continuous reading (sequential-monitoring) method: This is a

method to monitor operating conditions over a long period of time. The

merit of this method is that it enables a complete monitor of operational

conditions normally by selecting small number of workers (or machines)

and by monitoring and keeping a record of every single phenomenon that

takes place. While, the demerit is a high cost of analysis due to a

selective target of monitor relative to the efforts made for monitoring.

6.5.2. Snap-reading method (work sampling): The method to monitor the

subject instantaneously, represented by the work sampling method, is

broadly utilized today to compensate the demerits of continuous reading.

It makes it possible to observe a number of subjects simultaneously with

less energy. The demerits of this method, however, are that the extent of

observation can be superficial and that detailed qualitative analysis mightbe difficult.

6.6. Procedure of sequentially-monitoring

method6.6.1. Monitoring tools:

Stopwatch, monitoring sheet

6.6.2. Procedures:

1. Define purpose of analysis

2. Decide subjects and extent of monitoring

3. Decide what to monitor

4. Decide time frame for monitoring: In case the fluctuation of production

is expected, the time frame for monitoring the operational condition

should be long enough to cover such changes. Regularly, with a unit

of day from staring and finish times monitoring is carried out for

three to five consecutive days.

5. Prepare for monitoring

6. Fill in the required items in the monitoring sheet7. Execute monitoring procedure

Before starting monitoring process, define the extent of details to be reported

with respect to the subject-worker or operational conditions of facilities. In

case the purpose is to improve task process, categorize the monitoring items to

lead to the improved operational management, by working hours, break time,

waiting, material transport, and briefing time and record all the time period

required for such items

Analytical unit varies, depending on the length of cycle time for the target

operations and on whether the operation is mainly manual or machine



operation. Generally, it is often the case, where the analysis is carried out by

the minute.

If there are- ample resources for monitoring, more than two subjects (workers

or machines) can be observed at the same time, on the conditions that the

nature of the work of two subjects is similar, working environment is the sameor close enough

Always write down in the margin all the problems felt or clues for

improvement while monitoring the subject.

1. Organize the monitoring result

2. Examine the summary result

6.7. Organize the monitoring result When monitoring process is finished, organize the result based on the data on analysis

table and summarize them so conclusion can be obtained easily. It is preferable toorganize the item by work classification. (Refer to tables 6.1. and 6.2.)

6.8. Examine the summary result In the examination process, apply the concept of 5W1H (what, who, where, why, when

and how), four principles of making improvement, and brainstorming methodology.

6.8.1. Examples of checking items

Overall aggregated statistics (ratio)

1) Check whether the operation rate is high or low, relative to the other departmentof the same type (environment)

2) Examine the reason for low rate of operation; is it attributable to too much

allowance or exceptional workload? Why is there such excessive allowance?

Operating time (ratio)

3) Study the performance curve and find the reason for fluctuation. Can the fatigue

be reduced and facilitate equation of turnover by improving layout of work

environment switching to material handling, improving work efficiency orfacility and tools?

4)Why is it that the essential operation changes frequently?

5)Can the hourly business fluctuation that occurs within a day be even out?

6)Is the division of labor or assembly-line operation possible; is there not the

room for mechanization of process?



7)Focus on working hour, extent of fatigue, and product quality of the

essential operation and come up with reform measure for each

8)Is operational guide sufficiently given before operation is started?

Allowance time (ratio)

9) What is the largest content of allowance? Is a allowance ratio justified?

10) What is the cause of waiting time?

11) Are there a proper number of grinding stones for cutting tools? Can the

centralized tool grinding or distribution of tools be possible?

12) Is the location where the parts are placed best organized for operation

and other steps?

13) How long is the delivery time? Should the worker take care of the

shipment of the processed products or should the designated delivery staff

handle shipment?

14) Are delivery vehicles and systems in the proper condition? Is repetition

of handling products avoided?

15) Is there any problem in the work environment, such as lightning, office

temperature and humidity, dust, noise, and smell?

16) Are the trash cans or scrap collection boxes put in order?

17) Who prepares and clean up employee lunch?

18) Are the tools and technical drawings managed in good manner? No time

loss in the lending procedure for such tools and technical drawings?

19) Are there any claims handling process pertaining to parts materials?



Table6.1. Ratio-delay Sheet (Survey on Task Performance)

Date of Survey: from 8:00 to 17:00

Name of factory: Machine factory Name of office: Cutting operation Measuring staff: No.1Code Name of worker Title of

operation

Age Experience Effort Content of

task

(Main

operation

A: cutting

B: drilling

C: screw

cutting

D: Getting

materials,

putting on/ offOperation,

removal

(supplement al

operation) H:

Counting -

measurement

(Allowance) (Non-

operational)

Chatting, slow

to start

Work, Finish

earlier than

predetermined

Break

smoking.

E: Number,

Check

number of

materials

F:

Organize

product

G: Blade

sharpening

Briefing

Bathroom

Break

Water

break

(coffee

break)

A Shaft cutting 25 5

years

2

months

Average Drafting,

screw cutting

Table6.2. Spreadsheet for Operational Analysis



Name of factory Name of office from 8:00 to 17:00 Measuring staff Division Content

8 9 10 11 12 1 2 3 4 5 6

Subtotal total Rate of

correction

W o r k i n g h o u s e

O p e r a t i o n

Essential operation

Cutting 8 15 10 8 9 15 10 11 263

(54.8)Drilling 7 13.5 14.5 9 10 11.5 12 9

Screw cutting 8 11.5 14.5 11 9 13.5 14 9

Incidental operation Putting materials on/off 5 8 12 6 5 8 10 5 77

(16.1)Measurement 4 1 1 2 2 1 6 1

Incidental operation Prepare materials 9

(1.9)

Subtotal 41 49 52 36 35 49 52 35 349(72.8)

A l l o w a n c e

Operational

Allowance

Blade sharpening 3 4 4

48

(10.0)

Check number of materials 4 4 7

Organize product 1 6 7 1 7

Management

Allowance

Briefing 6 5 6

16

(3.3)

Personal allowance Bathroom break 3

12

(2.5)

Water break (coffee break) 3 3 3

Fatigue related

Allowance

Subtotal 9 8 5 13 14 8 5 14 76(15.8)

Non- operational

Chatting 3 3 3

55

(11.4)

Finish earlier, slow to start

work

7 8 8 11

Break 3 3

Smoking 3 3

Total 60 60 60 60 60 60 60 60 480(100)



Chapter Seven: Multiple–Activity Analysis

The multiple-activity implies a joint work of a man and a machine, or of two or more people.

The multiple-activity analysis also implies an analysis to optimize the process of thesemultiple activities

The word multiple implies a status where constituting parts have their own area while they

are interrelated to each other, thus aiming to achieve a concrete, direct object as a whole unit.

7.1. Multiple-activity and its analysisWe can see quite a lot of such multiple-activity around us, for example, work to apply an

automatic forwarding by using a lathe or a milling machine, work to erect an electric

pole, duplicating work using a copy machine, operations in hospitals, washing or cooking

at home, etc.

When turning our eyes to a broader scope such as team work among workers in the fields

of marketing, manufacturing, purchasing and quality assurance, or a transition work to

the multi-programming in computer operations, we can see the approach utilizing the

multiple-activity analysis will have a tremendous amount of applications.

By taking note of the processes of these multiple activities that are performed by

two or more objects on a single paper with a common time scale, we can clearly

display the mutual relationship-the status of a joint process in addition to the

order of time series of respective work in detail. This also enables us to make an

analysis to enhance the efficiency of the joint process, including elimination of

idle (non-value-adding) factors and the time. For time unit, DM (1/100 min.) or

M (min.) will be mainly used.

Generally, this multiple-activity analysis results in changes in work procedures

resulted from elimination or reduction of idle factors, division of work, layout,

etc.

Sometimes, processes of the multiple-activity analysis will not be stated or

analyzed without using a time scale, but such usage is usually limited to cases

where an outline review is urgently needed or to the preparatory case for the

analysis using the time scale. Therefore, we will not refer to this usage here.

7.1.1. Purpose of multiple-activity analysis

Analysis will be mainly done in the following cases:

Enhancing joint-process efficiency during the design or improvement

of work activities that are performed in a man-machine system.

Enhancing the joint-process efficiency during the arrangement or



facilities and streamlined layouts of machine facilities, from the viewpoint of

good joint-process efficiency.

7.2.2. Analysis procedures

Prepare a printed "man-machine" analysis form, an observation board, and astop watch or a wrist watch.

Fill out the name of object, process, machine used, worker, researcher and date

of research.

Prepare a simple chart indicating locations of machine, worker, and object.

Observe the work procedures of the worker and the operating order of the

machine.

Fill out the working status of the worker and the machine following the

elapsed time by using a stop watch, etc.1

During this process, in particular be

careful to take note of the work details of the worker while the machine isstopped. Also, be careful to correctly grasp the interrelationship of the man

and machine.

Upon finishing the observation, calculate the cycle time, net time and idle time

to obtain the idle percentage.

Proceed to review various kinds of improvements.

1)- To be observed through the continuous observation method

7.2.3. Example of improvement obtained through man-machine analysis

application

Improvement in molding work: Figs 7.2. and 7.3. show man-machine analysis

charts applied to a plastic molding work. Fig. 7.1. shows the work area layout

before and after improvement.

Previous method: The shaded area shows the time period when the machine is

performing the molding. During the time period, when a product is taken out

and the worker starts the next procedure, the machine is shut down, which is

shown by the plain white area.

The time period when the worker is taking out the mold from the die and

pouring the next material into the die is shown by the shaded area. During thetime period when the machine is in operation, the worker is just watching the

process, which is shown by the plain white area.

In this case, through the observation of the interrelation of man and machine,

you will see that the worker is waiting while the machine is operating, and the

machine is shut down while the worker is working.

New method: By employing the new method, the idle time has been reduced by

providing the worker with two machines.

Operation of two machines by one worker was made possible by shifting the

molding cycle of two machines. This is because the time required for the workerto take out the molded product from the machine, pour the next material into the



die and insert the die into the machine is shorter than the time of the machine to

complete molding.

As a result, the idle percentage of 60.8% in the previous method was reduced as much as to

8.3%. Fig. 3-3 shows the man-machine relationship of this case.

Figure 7.1. Previous/New Layouts for Plastic Molding Work

(Previous Method) (New Method)



Fig.7. 2. Man-Machine Analysis Chart of Plastic Molding Work in Previous Method

Date: Observer:

Product Name

DC8 Spinning Machine Pans

Present New Reduction

Cycle 194 DM DM DM

Process Name Worker Net

worker 76

Machine 143

Idle Time

Machine Name

Manual Molding 2-2

Worker 118

Machine 51 Idle Percentage

Worker 60.8 %

Machine 26.3 % DM Worker Machine DM

20

40

60

80

100

20

40

60

80

1. Take out the die.2. Clean the machine and

die with an air gun.3. Disassemble the die and

take out the mold.4. Assemble the die and

pout the material .5. Insert the die into the

machine and start theoperation.

6. Measure the material.

6

2

1

3

1

4

3

5

1

7

6

20

40

60

80

100

20

40

60

80

Fig.7.3.Man- Machine Analysis Chart of Plastic Molding Work in New Method Date: Observer:

Shutdown

Molding

Shutdown

51

194



Product Name

DC8 Spinning Machine Pans


Cycle Time 194 DM DM DM

Process Name

Molding

Worker Net

worker 76

Machine 143

Idle Time

Machine Name

Manual Molding 2-2

Worker 118

Machine 51

Idle

Worker 60.8 %

Machine 26.3 %

DM Worker Machine DM

20

40

60

80

100

20

40

60

80

1. work 1 on Machine I

2. work 2-4 on Machine I

3. work 5 on Machine I4. move to Machine II5. work 1 on Machine II

6. work 2-4 on Machine II

7. work 5 on Machine II

8. work 6 on Machine II

9. move to Machine I

10. work 6 on Machine I

20

40

60

80

100

20

40

60

80

7.2.4. Man and multi-machine analysis chart

The man and multi-machine analysis chart analyzes and records the interrelationship

of respective work steps when multiple machines are operated by one man. (See Fig.7.3.).

Molding

51

194

6

43

51

132

162

99

Shutdown

194

Molding

107

Machine I Machine II

Shutdown



7.3. Multi-man chart A multi-man chart is a process chart which records the status of an interrelationship between

multiple workers when they perform a single task together.

7.3.1. Use of multi-man chartWhen multiple workers are performing a single task in a team, the situation tends to

give a heavier work load to a certain worker, while others are simply watching the

worker's job. Under such circumstance, it is hard to expect improvement of a certain

worker's work efficiency, arid you have to plan to have work effectiveness from all

workers while watching the relationship between them.

When this occurs, it will be effective to make a study by using one single chart - the

multi-man chart. For example, the chart can be used when you wish to divide the job

at an appropriate level and re-assign the job to make the job amount of each worker

even, or when you wish to find out the most time-consuming work in order toimprove it.

7.3.2. Observation procedures

To give multi-man chart analysis, it is necessary to correctly grasp the

interrelationship of time needed to achieve respective jobs. For this scale is common,

and record the work details following the elapsed time. During this process, be sure

to watch the interrelationship of time in each work step.

7.3.3. Example of improvement obtained through multi-man chart application

Improvement in inspection/repair work of centrifugal separator

Previous method

The vertical type centrifugal separator designed for continuous operation is equipped

with an additional scraping device, which allows automatic separation of dewatered

stuff, on conventional type of separator. Usually, disassembling work to inspect the

bearings of the frame requires removal of the scraping device and basket (rotating

part) in this order. The cycle time is 345 minutes (5 hours and 45 minutes). The idle

percentage is 42.0% (145 min.) even for part assembling worker A, who has the least

waiting time, and as much as 81.2% (280 min.) for a setup worker. (See Fig. 7.4.)

New methodThe worker was convinced that the basket could not be removed before taking the

scraping device away, just like of small-type centrifugal separators. The new machine

was redesigned to be of larger size, and workers can now work simultaneously on top

of the machine.

Fig. 7.5. shows that working simultaneously reduced the cycle time, the idle

percentage of part assembling worker A has been reduced to 31.5% from 42.0%, and

that of assembling worker B to 53.1% from 60.3%. The new method shows the status

where the relationship between worker A and B has been simply substituted. But, if

workers C and D have no other work on hand, this job can be handled only by twopersons just by promoting so-called multi-skill training on workers. Moreover, if it is



possible to stop the assembling/inspection work of the scraping device for a moment

during the operation, the cycle time can be almost the same of that of the new method.



Figure 7.4. Multi-Man Analysis Chart of Inspection/Repair Work in Previous Method

Date: Observer:

Product Name:

T -60

Presen

New Reduction

cycle Time 345 M M

Net Part Assembling worker 200 Assembly Worker B 137

Process Name

Repairing Scraping

Device Inspection of

Worker

part Assembling

Worker A Assembling

Setup Worker C 65

Finishing Worker D 70

Idle Time A 145

B 208

Machine Name C 280

D 275

Idle Percentage A 42.0 %

B 60.3 % C 81.2 %

D 79.7 %

Part Assembling Worker Assembling Worker B Setup Worker C Finishing Worker D

1. Removal ofScrapingdevice

2. Disassemblingof scrapingdevice at workshop

53

140

285

345

53

105

115

130

215

240

285

345

105

115

130

200

215

240

345

345

200

130

10. Installing ofscraping device

3. Loosening thebasket fixing bolts

5. Hanging the wires

4. Lifting up 5. Lifting up 8. Inspection of bearingsReplenishing the grease

6. Lifting down

7. Installing thebasket in position


9. Tightening thebasket fixing bolts



Fig. 7.5. Multi-Man Analysis Chart of Inspection/Repair Work in New Method

Date: Observer:

Product Name

T -60


cycle Time 345 M M

Net Part Assembling 200 200

Assembly Worker B 137 137

Process Name

Repairing Scraping Device

Inspection of Grease

Worker

part Assembling Worker A

Assembling Worker B

Setup Worker C 65 65

Finishing Worker D 70 70

Idle Time A 145 92 53

B 208 155 53

Machine Name C 280 227 53

D 275 222 53

Idle Percentage A 42.0 % 31.5%

B 60.3 % 53.1%

C 81.2 % 77.7%

D 79.7 % 76.0%

Part Assembling Worker A Assembling Worker B Setup Worker C Finishing Worker D

1. Removal ofScraping device

3. Disassembling of

scraping device atwork shop

53

140

232

292

53

52

62

162

187

232

52

62

147

162

187

292

29211. Installing ofscraping device

2. Loosening thebasket fixing bolts

4. Hanging the wires

5. Lifting up

5. Lifting up 6. Inspection of bearingsReplenishing the grease

7. Lifting down

8. Installing the

basket in position


9. Tightening thebasket fixing bolts

345

147

77



7.4. Multi-man and machine analysis chart The multi-man and machine analysis chart is obtained by combining the man-machine

analysis chart and the multi-man chart, and the purpose of this chart remains the same.

In the case of the man-machine analysis, improvement in the multi-activity efficiency isusually sought for based on the functions of machinery while the multi-man analysis aims at

rearranging of work, considering the interrelationship between workers. Also, it should be

noted that while executing the multi-man analysis the relationship between workers and

machines must be considered from all aspects.

7.4.1. Points to be Improved in Multi-Man and Machine Analysis

Improvement in Lumber Work

Previous Method

The cutting of a long lumber into several pieces of standard sizes using a circular saw isperformed by three people, called a push-man, a pull-man and a take-man respectively. The

push-man brings lumber on the floor up onto the sawing bench with the cooperation of the

pull-man. The pull-man cuts the lumber at right angles, and the take-man takes the cut lumber

from the sawing bench and stacksJt in a specified area. (See Fig. 7.6.)

New Method

Since the lumber is stored on the floor, the push-man had to bring them up onto the sawing

bench. This action was eliminated by employing an angle bench which is as high as the

sawing bench. Also, because the lumber is long, the push-man had to push it at a right angleto the saw teeth. This problem was solved by drawing a line on the sawing bench. (See Fig.

7.6.)

In this case, the pull-man is supposed to completely perform the job without any break, but it

is recommended that the following points to be considered to ease the situation:

(1) Give further review to adjust the division of work between the pull-man and the take-man.

(2) If there is no room to adopt the above (1), study adoption of alternating work system with

the take-man.

(3) Introduce machines or an automated system for certain jobs.



Figure 7.6. Previous/New Layouts for Lumbering Work

( Previous Method)

(New Method)

Cut Lumber

Take - Man

Stack on floor

SawSawing Bench

Push - Man

Pull -

Man

Lumber

Stack on Floor Scraps on Floor

Box for End Blocks

Angle Bench

Scraps Take - Man

Angle Bench

Cut Lumber

Box for End Blocks

SawSawing Bench

Line

Pull-Man

Angle Bench

Lumber



Chapter Eight: Designing an Assembly

Process and Line Balancing

Line balance means balancing the time required between respective workstations which

constitute a production line. For a line production system, the line balance will be an

important factor. Incomplete line balance will result in congestion of work in process or work

waiting to be done at multiple work stations, thus affecting full utilization of facilities and

labor that is the key features of a line production.

If the manufacturing time at one certain work station is a little prolonged, the entire

production line will be affected by the delay, it will be impossible to have perfect line

balance, but efforts to reach such a goal will become significant for an exclusive system.

Even if the production line is fully employed, the same idea should be applied to products

that are manufactured in quantity or groups of similar products. If the line production is

partially employed, this idea will directly apply to the area involved.

8.1. Studying the line balance8.1.1. Pitch Diagram: The pitch diagram is suitable for studying the line balance.

The diagram depicts the schedule of time required for respective work stations

which constitute the line.

Fig.8.1. shows an example to the pitch diagram

DM

70

60

50

40

30

20

10

Pitch Time

47 40

60

51 45

50

Net Time

Process Name a B C d e f

No. of Workers 1 1 0 3 1 1

Element of work (1), (2) (3),(4),(5) (cooling) (6) (7),(8) (9),(10),(11)

General Float Time Balance Loss



8.2. Balance efficiency and balance loss ratioIt is recommended that to be used the scale of balance efficiency (also called line efficiency)

or balance loss ratio when you wish to evaluate the line balance of your present

manufacturing system or to guess the line balance for your new manufacturing system.

In general, the balance efficiency scale will be used for planning a new line, and the balance

loss ratio scale will be used for improving the line efficiency because of the unsatisfactory

balance loss ratio of the present line.

During the experiment, if the balance efficiency comes down to 85% or below (i.e., the

balance loss ratio exceeds 15%), you will not be able to expect good results from the

production line. Therefore, if you have a figure around 85%, you should study the plan

particularly carefully.

The following are the calculation equations for the balance efficiency and the balance lossratio.

Balance Efficiency =max.

1

T N

Ti N

i

Balance Loss Ratio = 1- Balance Efficiencymax.

max.1

T N

TiT N N

i

For your reference, the Balance Loss Ratio equationmax.

max.1

T N

TiT N N

i

It will be used sometimes just like the case of obtaining the Float Time Ratio. Where,

N: No. of work stations (to be corrected by No. of workers when some stations

have multiple workers)

Ti: Time required for each work station

T max: Maximum time required (required time for bottleneck stations)

Next, as shown in Fig. 1, calculations are made for the balance efficiency and the balance

loss ratio.

N= 8 (although there are six stations, there should be eight, since three persons are employed

at the work station d)

T max =60

Therefore,



Balance Efficiency (%) = %3.82100608

395

Balance Loss Ratio (%) = %7.17100608

395608

As seen in this example, the balance status is 82.3%, which is not satisfactory, and some

improvement is necessary, including moving of work element, partial introduction of

machines, and introduction of automation systems. For this purpose, the following points

should be considered:

a. To carefully examine the dispersion of time requited at respective work stations.

If the dispersion is significant, you have to first resolve the cause and ensure stability. If the

dispersion is unavoidable for the time being, you have to give considerations including

insertion of work in progress between work stations.

b. To establish matching pitch time this is calculated from the scheduled manufacturing

quantity.

The pitch time is the interval between the output of products (and the objects) and it equals

the maximum time required at the problem work station (usually, the general float time will

be included). For such assembling or wrapping work that requires less investment in

facilities, you have to consider measures to improve the balance efficiency, including an

increase in pitch time, which is calculated for a single line by two or three fold, that is to say,

an increase of lines to two or three.

It will be worth studying, from the aspect of motivating the workers, how to expand the scope

of work (to broaden the work responsibilities) of each worker.

8.3. Improvement in line balanceVarious methods may be applied to improve the line balance. But, in the case of machining,

improvement is generally harder to achieve than with assembling work since it is difficult to

divide the work into a lot of segments.

If improvement is examined through the observation of the present situation, it is usually hard

to find out the float time since the workers are seemingly handling various assignments,

particularly including:

a. Supplying materials to the line

b. Extra inspections

c. Applying lubricants, attaching labels and tags

d. Slowdown of work pace



Therefore, you are requested to make more careful observations or rating. In this case, self –

improvement such as by circle activities will be recommended.

8.5.1. Machining Line

a. Improvement in work: The best method will be improvement in the problem

work stations.

b. Change in Machine Speed: This can be frequently easy and practical.

Basically, increase in machine speed is favorable, but in some cases, the

higher- speed machine can be shut-down for a while, and various

supplemental operations can be performed during this period.

c. Placing the Work in Process: (Overtime in work Stations Lacking in

Capability, Employment of Two Shifts)

This method presents several weak points including the usage of extra floor

space, necessity of control of actual products and obstruction to maintenance

work. This is, however, the simplest method, but this cannot be applied to forcontinuous operations.

d. Using Machines from Other Lines: This is practical when the number of

bottleneck stations are one or two, An expensive, high performance machine is

frequently used among multiple lines.

e. Mixed Line with Similar Products: Manufacturing similar products on a single

line will sometimes result in the improvement of line balance.

8.5.2. Assembling Line

a. Re-arrangement of Work Stations by Re-assignment of Element Work. This

method is most frequently employed.

b. Balancing by Combining Work. If certain work cannot be further divided,

such work should be grouped together and assigned to one worker to ensure

the balance.

For example, grouped work consisting of three different jobs is alternately

assigned to five workers in cycle. Sometimes this method may require shifts of

workers or placing work in process.

c. Shifts of workers (double assignment to other work)

d. Improvement in work

e. Placing work in process

f. Improvement of workers' performance through instruction, training, assigning

skilled workers, etc.

8.5.3. Principles of Division/ Combination of Work

a. Try to avoid assigning two workers to one single job. In case the work time for

a work station is twice as much as the average, it is recommended that the

work is divided into two so that the two persons can perform different jobs,

rather than two workers performing the same job.

b. Separate heavy- duty work from critical work. Try to avoid placing critical

work right after the heavy – duty work.



c. Separate difficult work from simple work. Separate work which requires great

skill form simple work so that less work skill is required.

d. Concentrate work relating to one single part. Distributed working points make

the work inefficient. For example, when working on the front and back side of

a product, you sometimes have to reverse the product.e. Concentrate similar work. Concentrating similar work will result in

improvement of skill, and less frequent change of tools, thus making the work

economical.

f. An increase in the number of work stations that require balancing (when it is

100 or over in general), will increase losses due to accidents or it will be

difficult to control. Therefore, try to have a break by providing an intermediate

stock area.

g. Do not allow workers to use a lot of tools in one work station. Increase in the

number of tools may make the worker nervous about selection of tools. The

lesser, the better.

Experimentally, the following are recommended:

Pitch Time (min). 0.2 0.5 1 to 2

No. of Tools 1 2 to3 3to 4

h. Adjustment with Sub Line: When the process time is shorter than the pitch

time, absorption of sub- line work should be considered, or. When the pitch

time is shorter than the process time, a part of the work can be assigned to the

sub- line workers.

8.5.4. Reasons for providing sub-Assembling (for Assembling Work)

a. When it is easy to work on the same parts at one time, e.g., when the parts are

relatively small (or large).

b. When assembling requires a large area, the work can be shifted to the sub-line,

thus making the main line shorter.

c. When a jab has property that may obstruct the main line work (precision work,

flushing, etc.)

d. When a large or complex jib, or press machine is required.

e. When the sub – assembly line handles such work that is common to severalproducts (applying washers, etc.)

f. When flexibility is needed for the main line.

8.6. Float timeWhen a worker is working on a line production, the worker cannot take breaks etc., at his or

her own will. Therefore, you should give careful consideration to the length of float time in

determining the pitch time.

The following methods are available for setting the float time:



a. Adding a float time for each work station (usual method)

b. Stopping all lines at the same time for a break. With this method, the float time is

tremendously reduced, and instead, a grand break will be given at 10 o'clock in

the morning and 3 o'clock in the afternoon, for example, by stopping all the

conveyors at the same time.c. Placing relief persons. In order to give the workers a break without stopping the

conveyors, relief persons will replace workers having a break (also they will

relieve workers when they take a day off or they leave the station to do their

needs). It is mandatory for relief persons to be capable of handing a broad range of

jobs and usually they are in charge of repair work, instruction of freshmen, help to

other lines, supplying parts, etc.

d. Leaving some conveyors unused (products are manufactured without using all the

conveyors)



Consecutive

operating

analysis

Work

sampling

analysis

Chapter Nine: Work Sampling and its

Application

There are two ways to identify the operating rates of workers and machines per day.

(1) Monitor and record operating hours of workers and machines on-a-case-by-case basis

(2) Determine the proper time period during a day for monitoring operation. For example,

monitor 30 times a day and register and analyze the observation. If the subject

workers/machines were operating/operated 27 times out of 30 times observed,

operating rates would be 0.9 by dividing 27 by 30. The operating rate is therefore

90%.

Fig. 9.1. Comparison between work Sampling and consecutive operating analysis:

In operation Not in operationWork sampling 62.5% 37.5%

Consecutive operation analysis 63.75% 36.25%

The method (1) is called the consecutive operating analysis and method (2) is the work

sampling. The work sampling method calculates operating rate from frequency of operation

rather than counting operating hours directly. The merit of work sampling is that it takes less

time to monitor and makes it possible for an observer to monitor while at work. Incomparison with the consecutive operating analysis, work sampling is suitable for the

Not in operation

In operation



operating analysis for a relatively longer time period such as a week or a month-long

analysis. In addition, this method can be used to monitor several workers and machine

operating conditions at the same time.

To understand the nature of work sampling, following example is cited. Suppose that the

operating rate of four workers (A, B, C, and D) were to be analyzed. With consecutiveoperating analysis, the operating hours of each worker (demonstrated in the shaded area) are

recorded every time monitoring is carried out as shown in Chart above. Suppose other

observer implements 10 monitoring during the time period specified with an arrow in Chart

above, the number of workers in operation would be checked against each time period.

In the case above, one can conclude that workers were in operation at 25 out of 40 monitored

occasions. In other words, the monitoring resulted 25 operative and 15 non-operative

occasions and the average operating rate among four workers is 62.5%. From the consecutive

operating analysis, the operating rate would be 63.75%. The difference of 1.25% in the result

of two methods represents marginal error of work sampling method.

Work sampling is superior to consecutive operating analysis, in the way it is easier to monitor

and organize result, it takes shorter time, and it can monitor many workers simultaneously.

The demerit of this method, however, is that it does not present the details of problems, nor

does it reveal the operating practice clearly.

9.1. Characteristics of work sampling method9.1.1. Comparison with consecutive operating analysis: Compared to consecutive

operating analysis, work sampling method has many advantages as shown in

Chart 1.

There are also limits of or inapplicable cases for which work sampling is used as

specified below.

The order of task performance cannot be registered. Reviewing the order of task,

which often helps find a major clue for improvement, is only possible with the use of

consecutive operating analysis.

Work sampling method does not always discover unproductive motion or task

element. For instance, if a worker is engaged in a particular job while the machine isunder suspension, there may be a chance for him to implement such a job while

operating the machine. (If the worker has a sufficient knowledge about the task, he

should be able to differentiate several tasks, which can be implemented while

operating machines.)

Slow-down of performance speed by worker cannot be detected. (This problem

could be solved, if the performance is rated while monitoring, which however requires

lot of skills on the side of the observer.)



Table 9.1. Merits of Work Sampling Method in Comparison with Consecutive Operating Analysis

Item Work Sampling Consecutive Operating Analysis

Measuring method Instantaneous monitoring of the operating

condition of the subject Consecutive monitoring of the condition of the

subject Monitoring tool Visual check Stopwatch or time

Degree of fatigue of

observer Not much Monitoring can be carried out

while being engaged with other job Very tiring Must concentrate on monitoring

Consciousness

(reaction) of the subject Does not affect observer Affects observer greatly

Monitoring subject One observer can monitor several subject;

Worker and machines can be monitored

simultaneously

One observer usually can monitor one subject;

Sometimes worker and machines cannot be

monitored simultaneously

Duration of monitoring Can be determined freely in accordance

with the purpose of monitoring Longer monitoring time period is not possible

Speed of data summary Fast Fast

Processed form of result Ratio Direct time duration Monitoring cost Low High

9.2. Application of work sampling methodWork sampling method is applied to the following purposes.

Identify problems related to workers, machines and materials

Identify and improve operating rate of workers or component ratio of

operation

Identify and improve the operating rate of machines and facility or non-operating machines by cause

Establish standard time

Estimate collateral task and rate of allowance to be integrated to standard time

Analyze and improve performance

9.3. Steps to implement work sampling9.3.1. Define purpose of monitoring - what task will be monitored? The purpose of

work monitoring should be defined first, as the subject, frequency, and items of

monitoring vary according to the purpose. For identifying problem area

(1) Investigate the performance to identify the area of improvement;

(2) Identify operating rate of machines and pursue their efficient use;

(3) Review performance and determine the most appropriate number of machines each

worker should handle;

(4) Identify the case for non-operations and improve the condition

For getting coefficients

(1) Find out rate of allowance in establishing standard time;

(2) Collect basic information to establish standard time of repetitive task;(3) Collect basic information to establish standard time of non-repetive task.



9.3.2. Seek for understanding of and support from concerned parties

9.3.3. Determine the range of monitoring subject

9.3.4. Determine the monitoring items and principles. The monitoring items are

determined in accordance with the purpose of the monitoring. After considering

and reviewing as many items as possible, 25 to 30 items should be selected.Then each monitoring item should clearly be defined to avoid a situation, where

wrong data are collected, which happens, if there is more than one observer.

9.3.5. Determine the number of operational data to be monitored. Being a statistical

approach, work sampling produces a few marginal errors. Though the required

number of monitoring can be sought from calculating the allowable marginal

errors, in practice, one can refer to the following table in choosing the number of

data, to meet the purpose of the monitoring.

Purpose of Monitoring Number of operational data

Preliminary study (to determine regular monitoring item) 100-400

Investigation on managerial problems (suspension, holding of work,

wrong shipment, etc.)

400 – 700

Improvement of operation 700-1400

Determine net working hours per one task 1100-2500

Determine rate of allowance 3300 – 4500

Table 9.2. Number of operational data based on purpose of monitoring

The formula for obtaining the number of operational data is as follows.

(Number of operational data) = (Subject worker) x (Observer) x (Number of monitoring/one worker)

In case there are five subject-workers and four observers, and the number of monitoring is 48

(6 times per hour multiplied by 8 hours a day), the number of operational data will be

calculated as 960 as in the following formula.

5 x 4 x 48 = 960

Thus the number of operational data (number of sampling) will be 960. Using the samplenumber of operational data in the chart above, number of monitoring can be counted

backward.

9.3.6. Determine the date and time of monitoring: Since the operating conditions

often fluctuate according to the date, day of the week and time, it is necessary to

decide them to minimize such fluctuations.



Fig. 9.3. Diagrams of defective fraction

Depending on the purpose of operational analysis, one must monitor operation, by taking into

consideration these fluctuations. When determining the time frame, an at-random time

schedule could be utilized. As far as a periodical time span of 10 to 15 minutes is avoided,

any time period can be chosen for monitoring during the operational hours.

9.3.7. Determine monitoring route

Decide the monitoring point

Decide which worker to monitor at that point

Fig. 9.4. Sample of monitoring route

9.4. Do's and do-not's for monitoring1. Do not stare at the subject worker when utilizing work sample method. (Observer

should consider himself a monitoring camera.)

2. Do not think too much during the assessment; wavering is reflected in the form of

errors while collecting and organizing data

3. Delay the timing and position of monitoring as the subject worker get used to

being monitored, if the monitoring is frequently carried out

4. Add a postscript when the irregular task was observed. Take into consideration

that the purpose is "not to keep an eye on the subject worker but to monitor

performance.

Mon. Tue. Wed. Thurs. Fri. Sat.

Non-operating

rate

Operating rate

O p e r a t i n g

r a t e

8:00 12:00 17:00

Defective fraction

Seated

operation

Operation

on one's leg

Monitoring route



9.5. Calculation of operating rateStudy instantaneous phenomenon of the subject over several times randomly, and find out

how many times each phenomenon was observed.

Suppose five work-units were monitored 10 times and the following frequency of occurrencewas observed for each motion of the total 50 subjects:

Classification of phenomenon Frequency of monitoring

Task performance //// - //// - //// - /// / - //// - //// - ////- //// - /// 43

Allowance/Non-performance //// - // 7

Table 9.3. Frequency of monitoring

From this data, the operating rate and rate of allowance/non-operative ratio would be

calculated as follows:

Rate of performance.......................................43 ÷ 50 = 0.86 = 86%

Rate of allowance/non-operative ratio ...................7 ÷ 50 = 0.14 = 14%

With operating hours per day being 8 hours, the total operating hours a day would be 412.8

minutes as:

8 hrs. x 60 min. x 0.86 = 412.8 min.

When the production per day is 100, operating hours per one product will be 4.13 minutes as:

412.8 ÷ 100 = 4.13

9.6. Aggregate calculation of observed dataThe observed data will be aggregated in the following manner.

1. Add up all the frequencies of monitoring per hour: sum up the data per hour

and check if the total is correct

2. Add up the frequency of monitoring by monitoring item

3. Add the totals of 1) and 2) above. Get the total by observed hours and by item

and check if the numbers were consistent. If they are inconsistent, calculation

is considered wrong, thus try totaling calculation again

4. Check if the aggregate numbers of monitoring are consistent between the

summary data and the numbers obtained from calculation. In other words,

check if the total of the number of subject worker/machine multiplied by the

number of monitoring matches the summary data.

5. For instance, if 5 subject workers were monitored 20 times a day, the number

of monitoring should be 100. Check if the summary data matches 100.

6. Obtain the ratio per monitoring item by dividing the number of observed data

by item. For example, if there were 36 operations of solder-jointing and thenumber of monitoring was 80, the ratio would be 45 % as:



36 ÷ 80 x 100 =45(%)

7. Add up the categorical ratio of monitoring items.

8. Summarize the monitoring results throughout the observed period.

The above six steps should be taken for all the monitoring processes. When all the

monitoring and summarizing processes are finished, register the results on thespreadsheet for operational analysis.

9.7. Review result of operational analysis and

improve work efficiencyGraphing out the result of operational analysis as indicated in the following chart facilitates

reviewing process. In addition, it is suggested to show the figures in the time graph for the

purpose of time-change-analysis, conduct Pareto analysis in descending order, or use the

Pareto analysis to reduce production cost. Following are some points of consideration foroperational improvement.

1) Compare the operating rate of the subject work unit with that of others;

2) Consider the reason for the low operating rate; is not the allowance or excluded time

period set side too much, and why too much allowance is there?

3) Find out for what task the largest time allowance was used, is the rate of allowance

applicable?

4) Study if there are time fluctuations in the performance of main task

5) Consider if division of labor or assembly line operation is possible

6) Study the length of waiting condition and find the reason for it



Fig. 9.5. Work Sampling Spread Sheet

Name of office:

Xx Assembly Unit

Date of

calculation

16,2003

Calculated by:

Masanori AsaoNotes

Category

of task Task monitoring items

Date by item Aggregated graph by item

10% 20% 40%Number of monitored

Composition

ratio (%)

O p e r a t i o n M

a i n o p e r a t i o n

Fill in the forwardingaddress/t e of shi ment

35 3.9

Put the main unit in the box 40 4.4

Pack the product 29 3.2

Put the product in the bag 195 21.7

Wrap with stapler 67 7.4

I n c i d e n t a l

o p e r a t i o n Take the product in/out of 16 1.8

Put the product on pallet 18 2.0

S u p p l e m e n t a

l

Putting unit together (incl. Bo 30 3.3

Change parts 67 7.4

Put units in basket 13 1.4 Shipment (of product and cartonbox

52 5.7

A

l l o w a n c e

O p e r a t i o n a l a l l o w a n c e

Putting needle in stapler 3 0.3

Walking around the work unit 65 7.2

Searching for materials/tools 56 6.2

Empty shipment 10 1.1

Coating 3 0.3

Cleansing 3 0.3

M a n a g e m e n t

a l l o w a n c e

Telephoning 15 1.7

Registering information in thebook

56 6.2

Briefing 68 7.6

Waiting condition 3 0.3

Cleaning up 3 0.3

N o n -

O p e r Chatting 8 0.9

Away from assigned position 45 5.0

Total 906 100%

Main op. 40.7%

Incidental op. 3.8%

Supplemental op. 18%

Operational al. 15.5%

Mgt allowance 16.1%

Non-operation 5.9%



Table 9.3. At-random Time Schedule 1

1 2 3 4 5 6

38 0.01 4 0.04 21 0.28 14 0.01 25 0.03 40 0.05

9 05 33 23 22 36 32 15 38 08 1. 09

16 17 13 44 14 44 2 23 18 15 16 12

32 28 26 50 40 52 27 30 23 55 9 16

20 43 9 1.18 29 58 7 41 28 1.18 21 33

18 1.01 34 30 26 1.15 26 50 22 36 29 37

29 25 22 37 18 20 18 1.12 16 47 15 38

25 53 17 49 6 35 13 32 40 56 32 54

26 2.06 7 2.04 25 38 28 52 7 2.07 8 1.12

3 09 36 26 1 2.15 10 2.06 4 19 36 26

6 13 16 31 34 30 20 10 31 36 38 35

35 23 38 44 3 36 38 26 6 55 5 36

22 47 19 55 39 46 29 43 32 3.02 27 59 30 3.03 30 3.17 12 56 31 57 21 10 22 2.29

8 06 28 29 5 3.32 16 3.06 29 23 18 3.00

10 20 12 40 38 37 15 15 9 29 39 37

13 34 2 4.01 36 50 34 17 27 38 2 4.04

1 4.16 14 18 13 59 17 28 3 4.02 28 08

14 54 5 38 31 4.11 36 30 17 14 26 15

40 5.07 23 48 8 45 33 42 30 51 4 40

2 34 32 56 7 50 5 4.05 36 5.12 6 5.02

28 38 40 5.17 2 5.05 24 32 26 30 31 07

7 45. 20 27 35 14 35 5.09 1 40 30 21

11 6.10 21 56 33 33 21 38 35 50 14 29 4 56 35 58 11 46 40 47 5 6.01 23 41

21 7.02 1 6.28 15 50 30 6.08 37 10 11 6.24

15 12 39 39 23 6.05 9 37 10 19 7 38

34 18 3 48 32 12 19 48 24 27 25 7.00

17 22 24 51 37 29 12 7.00 8 43 3 10

31 28 15 52 19 30 37 08 19 7.25 24 22

12 30 8 7.23 20 38 8 21 20 34 17 32

5 49 31 26 16 7.15 4 24 33 8.04 37 46

27 8.01 27 38 27 34 25 44 34 06 12 51

37 20 18 8.07 28 50 6 8.01 39 10 33 8.16

23 34 10 12 10 8.19 23 29 14 15 19 27

19 45 11 27 4 27 39 41 12 45 34 36

36 59 37 45 9 30 22 50 13 9.10 35 46

39 9.05 25 9.07 30 9.06 11 53 11 18 20 9.04

24 22 6 19 24 29 3 9.35 15 25 10 23

33 46 29 52 17 45 1 56 2 48 13 45



Table 9.4. At-random Time Schedule 2

7 8 9 10 11 12

13 0.26 11 0.25 17 0.14 19 0.11 36 0,02 31 0.08

8 48 8 34 10 37 16 39 9 08 20 11

23 58 2 52 39 44 10 53 24 28 3 41

2 1.46 40 1.13 19 48 32 1.11 13 31 38 44

17 48 16 23 12 50 28 30 10 1.04 14 53

37 2.10 4 30 31 1.05 20 51 30 15 4 1.00

30 25 15 34 20 18 18 55 26 41 9 24

24 40 27 37 4 44 3 2.01 28 2.01 34 42

9 46 25 58 30 2.12 25 14 5 40 30 54

29 56 9 2.27 14 23 24 20 22 51 37 2,13

22 57 19 36 13 45 27 21 35 3.05 12 22

11 59 30 48 16 50 6 46 1 16 18 3336 3.09 22 3.02 36 3.07 29 3.10 23 40 8 47

7 25 28 15 15 16 38 42 7 41 1 3.01

39 47 1 35 27 23 23 4.00 14 4.09 26 09

15 57 29 4.03 26 30 1 10 38 17 35 36

18 4.26 17 16 5 39 33 14 16 21 5 54

27 28 20 20 21 4.08 7 34 19 27 23 59

40 33 23 35 37 17 8 49 4 42 32 4.05

34 45 31 42 35 38 21 57 32 57 17 34

1 58 7 5.02 32 5.12 22 5.08 17 5.28 27 54

38 5.12 36 07 40 22 5 32 27 35 22 584 35 35 21 3 . 35 15 34 12 58 33 5.05

3 6.08 21 29 24 6.02 26 58 20 6.13 13 28

19 18 26 41 38 07 2 6.21 6 33 16 32

26 26 13 6.15 22 34 11 43 25 45 39 36

31 39 12 29 23 57 34 44 34 7.04 7 54

33 41 37 35 2 7.01 17 7.08 2 12 29 6.04

25 49 5 41 33 10 37 20 18 30 36 36

16 51 6 55 28 22 4 31 31 42 10 57

14 7.02 14 7.32 8 30 40 34 29 8.09 19 7.04

5 08 32 49 34 46 36 8.11 8 11 21 4621 8.00 18 8.05 7 52 31 17 21 30 15 50

20 05 38 25 11 8.02 13 27 37 43 24 8.11

10 19 24 45 25 16 35 34 40 49 40 20

6 40 39 57 18 41 39 41 11 56 6 31

32 49 10 9.02 1 9.09 30 44 39 59 11 9.14

28 9.06 33 21 6 29 9 9.00 3 9.05 28 26

12 34 34 30 29 33 14 06 15 28 2 35

35 53 3 34 9 55 12 33 33 48 25 58



9.8. Work sampling exercise9.8.1. Purpose of improvement

Company S is a reduction gear manufacturer, with the annual revenue of 9 billion

Dollars and about 350 employees. The company has focused its business on the

development of new products, due to the rising competition in existing product area

and weakening prospects for increase in demand. Several products have been

developed but have not contributed to the pickup in business performance, whilst the

competition has become severer.

As Company S has come to face a cost problem, it decided to focus on cost reduction

pertaining to existing products, as a top priority issue.

The basic strategy is as follows.

(1) Keep the current number of employees and conditions of machines and facility. The

manpower will not be enhanced nor will be there new capital investment.

(2) The target rate of cost reduction is 10% of direct labor cost of approximately 1 million

Dollars.

(3) Prioritize and select a specific work unit for cost reduction and avoid targeting the

entire factory. Share the result of cost reduction exercise with other unit horizontally.

9.8.2. Subject Work Unit

The unit to process warming disselboom, a small component, is selected as the

subject work unit for monitoring, since there was a problem of production in waiting

condition and the low rate of machine operation. This work unit uses the assembly

line system. Since there are a variety of products being handled, lot production

system has been utilized.

There are eight workers and thirteen machines. The number of machines handled by

one worker is between one and three.

9.8.3. Application of Work Sampling

(a) Monitoring method

In parallel with task process analysis, the work sampling method was appliedin the following manner.

(1) The duration of monitoring is 4 days; the number of monitoring per day is 40

(2) In case the monitoring subject is a worker, the same type of task element will

be separately monitored by unit of machine conditions, i.e., machine in

operation and machine under suspension. The condition of machine under

suspension means all the machines handled by the subject worker are under

suspension. In other words, if one worker handles two machines, both of them

should be in the state of being under suspension



(3) The machines should be monitored individually

(b) Exercise: analysis of resulting data

Chart 1 shows a total result of monitoring of the performance of a selected

worker. As the chart shows, the composition ratio is very low of 37.8%. Chart2 shows the data categorized by state of machines, i.e., machines in operation

or under suspension.

Figures 1 through 4 depict the result shown in Chart 2 in graph by operating

conditions (Figures 1 and 2) and by interfering factors (Figures 3 and 4).

From these charts and figures, identify the problems of this work unit, and

then consider the approaches to solve such problem and improve operational

efficiency.

Chart 9.1. Total Work Sampling Spread Sheet

Monitoring

item

Figures Frequen

cy of

task

Compositi

on ratio

(%)

Composit

ion ratio

(%)

Main

task

Primary task 446 - 35.1

Concomitant task 34 - 2.7

S c a l e o f l a t i t u d e

O p e r a t i o n a l l a t i t u d e

Size checking 31 3.9

19.7

Adjustment 88 11.1

Box packing 56 7.1

Delivery of

components25 3.2

Inspection 20 2.5

De-burring 25 3.2

Others 5 0.6

n v

r o n e a

l a t i t u d e

Briefing 8 1.0

31.6

Waiting 362 45.8

Regular

morning meet26 3.3

Others 6 0.8

Non-

operation

and others

Break 17 2.2

10.9Short-

42 5.3Away from

assigned

79 10,0

Total 1,270 100.0 100



<Machines in operation> <Machines under suspension>

Figure 9.7. Graph of operating rate

with machines under suspension

Concomitant task

2.3%

Non-operational

condition and others7.0%

Figure 9.6. Graph of operating rate

with machine in operation

Concomitant task

4.1%

Figure 9.8. Pareto Analysis Graph of

elements interfering with machines Figure 9.9. Pareto Analysis Graph of Elements Interfering

Operation with Interfering Operation with machines under



Chart 9.2. Work sampling spread sheet by condition of machines and by interfering factors

Condition of machines

Monitoring item

Figures Frequency of task Composition ratio

(%) Composition ratio(%)

I n o p

e r a t i o n

Main task Primary task 363 -- 37.0 Concomitant task 22 -- 2.3


O p e r a t i o n a l l l a t i t u d e

Size checking 24 4.0 Adjustment 56 9.4 Box packing 42 7.1 Delivery of components 13 22 181

Inspection 25 4.2 De-burring 15 2.5 Others 2 0.3

E n v i r o n m e n t a l

l a t i t u d e

Briefing 8 1.3 Waiting condition 338 56.8 356 Regular morning meeting 0 0

Others 3 0.5

Non-operation

and others

Break 2 0.3 70 Short-break/chatting 22 3.7 Away from assigned position 45 7.7

Total 980 100.0 100.0

U n d e r s u s p e n s i o n

Main

task

Primary task 83 -- 286 Concomitant task 12 - 41


O p e r a t i o n a l l l a t i t u d e

Size checking 7 3.6

Adjustment 32 16.4 Box packing 14 7.2 Delivery of components 12 6.2 25.2

Inspection 5 2.6 Others 3 1.5

E n v i r o n m e n t a l

l a t i t u d e

Waiting condition 24 12.3 Regular morning meeting 26 13.3 183

Others 3 1.5

Non-operation andothers

Break 15 7.7 Short-break/chatting 20 10,3 238 Away from assigned position 34 17.4

Total 290 100.0 100.0



Chapter Ten: Standard Time Measurement

Procedure

Concept of standard time is the time deemed necessary for a worker who has a talent for and

is proficient in a certain task to perform the task at a normal pace with the specified working

method and conditions in a normal work environment.

There are also other meanings for standard time such as:

Workload per proper unit time

Normal working pace

Accomplished workload

Following terms must be considered as well:

Standard time in a narrow sense: Standard workload and standard workforce

Standard time in a broad sense: Production planning, process control, coast

control. This not only demonstrates how far the operator has proceeded with

the task, but serves as the basis of production planning and cost accounting.

Standard time measurement is the digitization of the standard working method

in terms of time unit.

10.1. Giving concrete shape to standard time

measurement The time that is necessary:

1) For a worker with competence sufficient for the defined task

2) To perform the task in a good work environment

3) In a defied working condition

4) With a defined method and equipment

5) In a set period of time

We also use standard time for managing work and standardizing the operation.

10.2. Intended purpose of standard timeThe intended purpose of standard time can be broadly divided into three categories, as listed

below:

1) To use for the comparison, selection, and improvement of working methods

2) To use as basic information for production planning

3) To use for the evaluation of work efficiency and the estimation of processing cost

The purpose of standard time is to serve as administrative data the prevention of opportunity

loss.Opportunity loss = Actual time - standard time



10.3. Organization of standard timeAs shown in Figure 1, the standard time of an operation can be divided into "main operating

hours" and "preparation time". Each of which is further divided into "net time" and

"allowance".

Figure1. Organization of standard time

1) Operating hours and preparation time

Main operating hours: The time necessary to produce the product usually constituting a

majority of the working hours

Preparation time: The time required to prepare equipment to produce top-quality products

including lubrication, setup such as material setup and jig fitting, cleaning up after

completing production, material premarital, etc.

It is important to reduce the preparation time as much as possible.

(2) Net time and allowance

Main working hours and preparation time are each classified into net time and allowance. If

an automated machine that never has trouble produces products without any problems based

on a production plan to the process with certainty, no allowance is needed in the main

working hours. However, as even automated machines require preparation time before

starting operation and commonly experience minor stoppage, etc., allowance is necessary in

addition to the net time. When producing with human power, adequate allowance is required

separate from the hours necessary for the operation itself.

10.4. Intended use of standard timeProperly set standard time has wide application as a standard to control the production

activity as working hours for a defined operation method under certain conditions or as a

basic numerical value as long as the basic conditions of the operation are not changed.

1. For comparison of working methods, selection of better working methods , or

improvement

2. For balancing the working hours of multiple workers in a group operation

3. For determining the number of machines assigned to one worker

Main working hours

Preparation time

Standard time

Net working hours

Main working hours

Net Preparation time

Preparation time

General allowance

Special allowance

General allowance

Special allowance



4. To provide information about production such as the amount of production and the

production schedule

5. To decide on the sales price

6. As the basis of efficiency wage

7. For controlling labor costs

8. For measuring productivity and work efficiency

9. For deciding on the amount of production and the production schedule

10. For determining the requirements of equipment and labor and the percentage of

capacity based on them

11. For deciding on the amount of work per day that is fair to both labor and management

10.5. Things to keep in mind when setting

standard time1. Don't decide on standard time in a slapdash manner.

Standard time serves as a reference value for production planning, process control,

and evaluation of production indices in production activities. In this sense, standard

time has the same function as operation standards have in quality management.

2. Standard time should set by persons with sufficient competency and experience.To set standard time, you need to conduct various analyses such as operation analysis,

observation of time, rating, and examination of percentage of allowance and

preparation time. Further, standard time should be objective enough be accepted by

persons involved.

3. Standardize the working methods and conditions before setting standard time.

When setting standard time, it is important to standardize the work by a thorough

examination of the working method, work sequence, jigs and tools, working layout,

and environment.

4. Reset the standard time when the working method or condition is changed.

Work improvements such as a partial change of products, change in production

method, change of material, introduction of new jigs, and change in the organization

of work are carried out on a daily basis. It is important to amend the standard time

according to the content of the improvement after each change.

10.6. RatingRating involves making a comparative judgment of the normal pace and the pace of the

observed operation and adjusting the observed value in conformance to the normal pace.



To adjust the observed time, multiple it by the rating coefficient; this coefficient is shown as

the proportion whose denominator is the standard progress rate and the numerator is the

actual progress rate.

Net time = Observed time× Rating coefficient

= Observed time × Actual progress rate/ standard progress rate

...

....

r PS

r P At OT N

10.6.1. Rating coefficient

For operations with the same element tasks, the ideal rating must produce the same net time

regardless of the speed of execution.

However, values of the observed time as they are do not necessarily conform to the definitionof standard time. If the operation is carried is carried out by a high- level worker (a skilled

hand) or with a practically unsustainable level of effort, the operation can be carried out in a

short period of time. If you use this as standard time for planning the amount of work, there

will be no way to accomplish the plan and vice versa.

10.6.2. Need for rating

We cannot deny a lack of accuracy when evaluation the level of work performance due to the

element of subjectivity. Accurate evaluation requires training and skill. We must admit that

the procedure of rating is an unscientific one among the basic IE methods.

10.6.3. Factors that influence working speed

The working speed of a worker differs depending on his/ her willingness to work

(motivation), skill (competence), and work environment. Rating evaluates the magnitude of

these factors that influence workers.

We cannot definitely say what the normal speed is. There is no other way than to learn it by

repeatedly exercising and experiencing rating.

Normal speed means the speed at which a worker who is typical in every aspect including

degree of proficiency, aptitude, and motivation operates with normal effort following the

standard working method.



Table.10.1. Factors that influence working pace

Factors that influence working

speed

Major division Intermediate division

Willingness to work

Physical condition

Human relationship

Financial incentive

Mental stimulation

Skill

Physical condition

Aptitude

Opportunity to implement

Training

Level of technology

Work environment

Daylight/lighting

Temperature /humidity

Color

Air condition

Acoustic condition

10.6.4. Types of rating

There are many types of ratings but none are perfect; they all leave the final judgment to

human experience. Therefore, any method of rating requires adequate training andexperience.

1) Leveling method

In this method four factors that cause difference in working speed among workers, i.e., skill,

effort, environmental condition, and consistency are considered. Each factor is divided into

six to eleven levels and a coefficient is defined for each of them. Check the level of each of

the four factors for the actual operation, and up the coefficients of the levels to obtain the

adjustment coefficient, and calculate the net time by multiplying the observed time with the

adjustment coefficient. Tables 2 and 3 present an outline of the four factors.

Table 10.2. Organization of standardization (leveling) coefficient

Factor Evaluation Leveling coefficient

Accuracy of motion

Skillfulness, familiarization

Choose among

11 levels

A leveling coefficient is

defined for each level (See

Table 3)

X1

Willingness , enthusiasm 11 levels X2

Light, heat, ventilation, noise 6 levels X3

Fluctuation of time 6 levels X4

Total X



Table 10.3. Leveling coefficient (X)

Factor

Grade

Accuracy of

motion,

skillfulness,

familiarization

Willingness,

enthusiasm

Light , heat,

ventilation, noise

Fluctuation of

time

A A1

A2

+0.15

+0.13

A1

A2

+0.13

+0.12

A 0.06 A +0.04

B B1

B2

+0.11

+0.08

B1

B2

+0.10

+0.08

B +0.04 B +0.03

C C1

C2

+0.06

+0.03

C1

C2

+0.05

+0.02

C +0.02 C +0.01

D

(Average)

D 0.00 D 0.00 D 0.00 D 0.00

E E1

E2

-0.05

-0.10

E1

E2

-0.04

-0.08

E -0.03 E -0.02

F F1

F2

-0.16

-0.22

F1

F2

-0.12

-0.17

F -0.7 F -0.04

Leveling coefficient of work: X=X1+X2+X3+X4

Net time = Observed time × (1+X)

2) Speed rating

To determine the level of the performance of workers, you need to consider various factors,

Speed rating is a method used to evaluate performance only in terms it motion speed.

Therefore, you can obtain a rating coefficient just by comparing it with the actual working

speed, Setting the normal working speed at 100, the coefficient is 120 if the speed is deemed

20% higher than that and 90 if it is 10% lower. You can then calculate the net time using the

formula below.

Net time = Observe time × Rating coefficient/100

3) Pace rating

This rating method also makes an evaluation only in terms of motion speed. The small

difference here is that work is divided into several types and the normal working speed for

each type is decided by considering the fact that the normal working speed is different

depending on the type of the type of the operation. This means that analyzers need to learn

the basic standard speed of each type of work beforehand using videos for standard speed

training.

In the actual rating, first determine the type of work and then the rate while observing the

actual work.



4) Effort rating

The difference of individual workers' working speed can be caused by differences in their

committed effort to the operation. This method is different form speed rating in that not only

the working speed, but also the difficulty of the work is assessed. For example, it is natural

for the same work to be considered differently in terms of normal working speed depending

on the weight to be handled. Therefore, analyzers need to have past experience and

knowledge regarding various operations of similar levels of difficulty to those of the

operation to be observed.

5) Objective rating

This method evaluates the performance level based on the difficulty and speed. However,

what makes this method really different form the pace rating and effort rating is that it is

divided into two stages for easier rating and objective results.

1) Independent of the difficulty level of the work, the observer conducts speed rating by

comparing the single net working speed set by each workplace and the actual working

speed.

2) Next, determine the difficulty level of the work using the predetermined difficulty

level coefficient and adjust the value of the speed rating obtained in (1)

3) Net time is calculated with the formula below using the coefficient obtained in an.(2)

Net time = observed time × Rating coefficient × (1+ difficulty level adjustment coefficient)

6) Synthetic rating

This method performs rating using the PTS method (Predetermined Time System) and

numerical values instead of judging it during the observation.

A workplace is usually organized by product with all of the units doing similar work. This

means that there may be a small difference, but it does not make the content of the work

completely different.

10.6.5. How to proceed with rating

Rating is carried out alongside observation of the actual work by analyzers with sufficient

training and experience

Basic procedure of rating is shown below.

Step 1: Learn the standard net working speed beforehand through training.

Step 2: Try rating. After checking whether the work is conducted using the standard working

method, compare the standard speed concept you have learned through your experience and

the valid speed of the worker who performs the work in your mind.



Step3: Express the result of the comparison quantitatively. For example, if the standard speed

is 100% the actual working speed is expressed, if this is higher than the former by 10%, as

110%, and, if this is slower by 20%, as 80%.

Step 4: Multiply the observed time by this comparison coefficient as the rating coefficient for

adjustment.

For step1, there are various methods of rating training. Usually, operation videos shot at

various speeds are used in the training.

10.7. AllowanceTime allowance is the time that is appropriate for additional work, general delay, and delay

due to the physiology or fatigue of workers that are predictable in performing the work.

For various reasons, work sometimes needs "leeway" or "allowance" to some degree inaddition to the time absolutely necessary for the operation itself. Such time makes work more

effective in the long run in most cases. Inventory, capital, and personnel are usually planned

with normal leeway besides the necessary amount. Working time also requires brief

interruptions or additional time besides the net working time due to the physiology of

workers, way of work, handling of equipment/jigs, or management system. Therefore, when

determining the time necessary to produce a certain amount of output in a set period of time

at a given pace, proper allowance must be added to the net time.

10.7.1. Time allowance and percentage of allowance

Time allowance is added to the net time in the form of an additional percentage,

which is called the percentage of allowance. To obtain the percentage of

allowance, we measure or calculate the material- and personnel – related time

allowance deemed acceptable based on the operation research for proper length

of time, then sort out and convert the value into the percentage to the net time or

working time that were determined beforehand based on work measurement. In

short, the percentage for allowance is represented by the following formula:

Percentage of allowance = (Time allowance ÷ Net time) * 100

The percentage of allowance needs to be divided into material allowance and

personnel allowance. The material allowance is the element found necessary for

the operation. It is handled separately because it is difficult to include in the net

time because of the irregularity and lack of periodicity of its occurrence.

10.7.2. Types of allowance

Allowance is classified broadly into general allowance and special allowance

(Figure 2). General allowance is the Basic allowance usually given to any work.

Special allowance is the Allowance permissible under special circumstances such

as the particularity of the work, work structure, management technique, etc.



Figure 2. Classification of allowance

10.7.3. Steps of calculating time allowance

Below you can see the steps of calculating time allowance.

Step 1: Identify the items of allowance.

Step 2: Derive the percentage of allowance for each item of allowance.

(1) The percentage of fatigue allowance is calculated using the table of the

percentage of allowance, energy metabolizability, etc.

(2) The percentage of other allowances is calculated by observing the actual work

several times for one to several days using the operation analysis (work

sampling) method.

(3) Step: Calculate the percentage of allowance of the whole based on the

percentage of allowance of the individual items.

(4) Step: Calculate the time allowance by multiplying the net time with the

percentage of allowance.

10.8. How to determine standard timeWhen setting standard time, it is not enough to simply decide the standard time for the

operation without adequate planning, standard time is meaningless if you don't examine

thoroughly for what purposes the standard time will be used and make it suit the purpose /

intended use. To determine standard time, you can use the methods shown in Table 4 other

the one based on time observation. Therefore, you need to select a suitable method

considering the purpose for setting the standard time as well as the time and cost it takes.

Steps to set standard time



Step 1: Define the purpose for setting the standard time

Step 2: Select the method of setting the standard time

Step 3: Determine the operation and product for which the standard time is set.

Step4: Define the proper way to carry out the work.

Step5: Measure the net time of the main work.Step 6: Rate and adjust the observed time.

Step7: Determine the time allowance.

Step 8: Calculate the standard time of the main work.

Step 9: Determine the time of the preparatory work.

Step10: Calculate the standard time per unit.

The approach of this procedure is shown as the concept of standard time measurement in

Table 10.4. and Figure 10.3.

Table 10.4. Methods used for standard time measurement

Method Applicable work RatingAdditional time

allowance Accuracy

Stopwatch

method

Work in general where the same

elements are repeated, especially

cycle operations

Used Necessary High

Predetermined

Time

Standard

(PTS method)

Best suited to short – cycle

operations (because of their high

objectivity)

Not used Necessary High

Work

sampling

Work with long or no cycles, group

work, work in indirect department(This is the main method used for

estimation of the percentage of

allowance).

Used Necessary Relatively

low

Standard data

system

Suitable to work with frequent

repletion of the same work

elements locally of when the time

value depends mainly on physical

properties such as the dimension,

weight, and material of the things

handled

Not used Necessary Relatively

low

Estimationbased on

experience

Used when the operation cycle islong, the content of the work is

indefinite, and there are

experiential values of similar work.

Not used Necessary Low



Figure 10.3. Concept of standard time Measurement

10.9. Application of standard time10.9.1. Comparison of work methods

Some say that there are an infinite number of methods that can be used to accomplish on end.

It is safe to say that there are more than two. Objective and consistent standard time is useful

to compare and identify the best method.

10.9.2. To balance the working hours of the members of a group work

In earlier times, a single skilled worker used to handle a very long process of his own. Now,

however, it is common for several workers engage themselves in production based on the

division of labor in order to speed up the process of becoming proficient and to make quality

stable.

The man- hours of a group operation where several workers handle a short process based on

the division of labor is determined by the process that takes the most time in the group.

Therefore, for the higher efficiency of the whole process, it is important to make adjustmentsso that all of the processes are carried out in a similar working time. If you have a standard

time of each operation based on work measurement, you can use this to develop economic

organization.

10.9.3. To determine the number of machines handled by one worker

The standard value of the working time and that of the machine time obtained by work

measurement allows you to know the level of mutual interference for the number of machines

handled by each worker and determine the number of machines to be handled by one worker

to fit your purpose such as to maximize the production volume of the machines, to minimize,to maximize the efficiency of machines, or to maximize the efficiency the workers.



10.9.4. To provide information about the production plan

10.9.5. To decide on the sales price

For a healthy management, it is important to determine the appropriate price of products

before starting production. To do this, first you need to estimate how much time each

production process will take. It is also necessary to check the difference between the

estimated hours and the actual hours after starting production.

In such a case, standard time based on work measurement or reference information of

organized numerical values serves as the most reliable measure for estimation.

10.9.6. To use as the basis for efficiency wage

An efficiency wage plan is a system used to pay workers with high productivity a percentage

according to their output. If each worker can increase production according to his/ her

capability, it can be more effective to pay a premium for the increased production.

In this way, you can encourage the voluntary cooperation workers in the standardization of

the working method or improvement of equipment.

10.9.7. To control labor casts

Because standard time "shows the standard speed and output of work," supervisors can

evaluate work efficiency by comparing the performance of each worker with the standard

time and find ways in which to identify "work and workers that need training."

In the above – described way, you can control the labor costs that usually account for the

greatest part of production cost within a proper range and maintain the standard cost at a

certain level.

10.10. Reminder about standard timeThough many companies use standard time for management, most small and medium

enterprises are still a long way from using it effectively.

1. Some companies set standard time with a uniform percentage of allowance

(e.g., 20%). Such standard time should be reviewed because there must be

some difference among divisions.2. Standard time aims to prevent opportunity loss. What is significant here is to

improve work by analyzing the difference between the standard time and the

actual time.

3. In many cases, even if standard time is revised, there are significant

fluctuations of working hours among workers due to the insufficiency of the

operation standard and operation manual (This is often attributed to the morale

of the workers, but in most cases the root cause is that the operation is not

carried out with the correct movements as they have not been taught).

It is necessary to establish proper operation manuals and provide education/ training.



4. Field managers are required to prepare conditions for the standard time so that

workers can always work according to the standard time.

PTS: Predetermined Time Standards

Reference literature:

1. The Basics of IE, New Edition , Akihisa Fujita, Kenpakusha

2. IE Textbook for job Sites, Katsuyoshi Ishihara, JUSE Press

3. IE Method for Job Sites, Kinichi Ikenage, JUSE Press.



Chapter Eleven: Setup Within 10 Minutes

In this chapter we will try to carry out the single set-up to improve the time consumed and

standardization of procedure. Standardized sequence will be structured and some notnecessary movements will be discussed.

11.1. Types of set-up1. Switch- over of dies/molds

2. Switch – over of standards

3. Switch - over of objects and components: Switch- over of components arising

from a change in the product being produced

4. Switch – over of work: This describes such processes as the set – up of the

design, preparations for trial production, the set-up of the initial products, andpreparatory work for work to be carried out in the morning; usually, the

generic term for the switch - over of works is called "set-up".

11.2. Five measures for improving set-up

work 1. Formulate a production plan to reduce the number of set-ups: Through ABC

analysis, calculate the most economically efficient number of set-ups and

develop a pattern for production planning.

When formulating a weekly plan, create a plan in which there are as few set-

ups as possible and the number of set – ups can be equalized.

2. Seek to standardize components and dies through VA (value analysis thereby

reducing the number of set-ups:

Can dimensions be standardized?

Can the bores be standardized?

Can we change from machining to die processing?

Can we make a more simple design?

Can we dispense with any components?

3. Mechanize and automate set- ups: If ten or more set- ups are required eachday, think about mechanizing and automating set-ups.

Set-ups can be carried out within ten seconds through automation using a

rotary die configuration.

4. Improve and standardize the die mechanism: Use a boltless/fastener process

for the mounting and removal of dies, for example, the auto-clamper process.

Standardize and secure the die set it, so that only the cavity part needs to be

changed.

The ultimate improvement to the die/mold set- up is not switching over the

die/mold at all. Therefore, it is necessary to consider the die/mold mechanism

and develop a mechanism in which dies/molds are not switched over.



If a switch- over is absolutely necessary, it should just involve a cavity part

that can be held in one hand.

5. Build up small improvements that bring together knowledge gained on- site.

Make continuous operational improvements through the IE method.

11.3. Introduce a single set-up sequencethrough operational improvements

1. Gain an understanding of the reality of set- ups

Gain an understanding of the actual situation with regard to each process and

machine, and clarify downtime losses, thereby identifying improvement

requirements and priority issues.

Conduct delay study of key facilities

Using the IE method's continuous time reading, observe all processes, includingpreparatory work for the set- up, the removal of the old die, the mounting of the new

die and trial processing, right up until the first non- defective item is produced. Ensure

that you make a note of any improvements that you notice are needed during your

observation.

2. Classification of the details of the set- up process

Divide the results of your observation into preparation, removal, and

mounting, deciding the position, setting the standards, testing, trial processing

and adjustment, while at the same time classifying them as internal, external

and needless work. Internal set-up work that cannot be carried out without stopping the machinery, such

as the removal and mounting of dies/molds.

External set-up work is the work that can be prepared even when the machinery is

operating, such as the preparation and transfer of dies/molds.

Needless work includes meetings during set-up work, looking for things, and

adjustments that have to be made several times.

3. The first stage in making improvements is to identify needless work

Identify work that is not needed and eliminate the work.

4. Remove needless work in external set-up work

Remove work that involves searching, thinking or walking. Develop and use

trolleys equipped with the seven tools of set-ups, as a way of eliminating the

need to search for things. If the set-up work cannot be carried out by a single

person, organize set-up groups (teams) of two or more people.

5. Turning internal set-up work into external set-up work

6. Improving internal set-up work

Improving the tightening of dies/molds. Improvements to mounting and

removal through the use of bolts. Boltless fastener devices.

Eliminating adjustments by eliminating the causes of adjustment work.Unification of die heights. Unification of the height of the removable part of



the die holder. Setting of standards through the use of "male- female instant

fitting" processes (centering). Use of intermediary jigs.

7. Creation of a standard job sheet and training

Table 11.1. Noting Improvements That Will Halve Set-Up Times

Internal Off-line Needless Points for Improvement Specific

Methods

Preparation 1)Set- up checklist or

specialist trolley

2) Organizing groups

Removal/

Mounting

3)Setting dies at a uniform

height

4)Setting the removable part of

the die holder at a uniform

height

Deciding position /

Setting standards

5)Standardization of the clamp

tools

6)Mounting of the main body

for centering (male/female)

Trial/ processing

Adjustment

7)Improvements to adjustment

methods

Total

11.4. Creation of an improvement

implementation planDivide the improvement plan into those improvements that can be carried out straight away

and those that will require time, money, or technical consideration, and carry these out

successively, starting with the improvement that can be made immediately.

11.5. Standardized sequence for making

improvements to the set-up work 1) Set up everything that can be prepared before the machine stops.

2) Move your hands, but don't move your feet.

3) Do not move or dismantle the basic standards.

4) Remove the bolts completely.

5) Do not move the jig standards.

6) Adjustments are the biggest needless work. Adjustment are defects of the set- up

work, which require rework,

7) Change from analogue to digital adjustments.

8) Use racks and guides for mounting precipice dies.

9) At the same time as you change the die, push the other die on.

10) Zero set-ups are achieved through the use of common jigs.



11.6. Needless fine movements in the set-up

work In order to identify needless fine movements in the set-up work, carry out a survey of the

actual situation using movement analysis or the principles of economy of movement.

1) Waste in the preparations: Looking for, finding and carrying tools and material are

needless parts of the preparation work.

2) Waste in removal: With regard to the method used when tightening bolts using a

spanner, needless actions arise from choosing spanners according to the type and

diameter of the bolt if you hold the bolt up to the spanner (alignment). In order to

eliminate waste, bolt types should be unified. Only the last turn of the bolt has

significance, so all movements up until that point are needless. Accordingly, eliminate

bolts as tightening jigs as much as possible.

3) Waste in mounting

4) Waste in adjustments: Adjustments are rework resulting from failure in the set-up

work; or, to put it another way, they are imperfections in the set-up work. These

adjustments involve needless repetition that arises because the standard settings have

not been carried out accurately. The biggest waste in set-up is due to adjustment.

11.7. Procedure for die standardizationIt requires a great deal of effort and money to standardize one's own company's dies, so the

fact is that this will be difficult to do unless some kind of opportunity to do so presents itself.

1) Assume a standardized model such as the QDC (Quick Die Changing) method.

2) Carry out a survey of the true picture with regard to the current condition of the dies.

3) Create a standardization promotion plan using the active dies of the current press.

4) Formulate a draft QDC proposal for the active dies:

1) Standardize the mounting and removal of dies.

2) Standardize the die area and the standard setting.

3) Standardize the die plate.

4) Standardize the height of the material feed.

5) Select the die set, guide post and center alignment methods.

6) Use commercially available standard parts.

7) Standardize the structure by means of the auto- clamp method.

5) Use a common die set and change only the cavity part.

6) Formulate a schedule for switching to QDC.

7) Switch – over to QDC, tests.

8) Create and standardize die design standards.



Chapter Twelve: Design of a U-Shaped Line

12.1. What is a U-shaped line?U-shaped line is a facility lay out for the Just-In-Time production system. It has two main

characteristics.

1. It lays out the shop, so that the processes are arranged in the right sequence and form

a line.

2. Since the line is arranged in U-shape, the start and the end of the cycle operation are

at almost the same points, thus the traveling distance becomes shorter.

In other words, the layout where the process is arranged following the flow of the products or

material is called a U-shaped line.

Although the U-shaped line is mainly used for machining processes, it is also applicable to

the assembly process.

12.1.1. Conventional facility arrangement

1. In this sort of arrangement, the workshop consists of similar machines based

on job-shop type arrangement.

2. Operators and machines are fixed and work pieces move.

3. Production is carried out by lots.4. Stock is built up.

5. Transportation-loss (waiting for transportation) is generated.

Drawbacks of the conventional floor layout consist of working in process and unnecessary

products tend to accumulate. The lead time is long.

12.1.2. U-shaped line arrangement

1. Processes are so arranged that, while moving from one station to the next, a

product of a component approaches to more and more finished form. Thearrangement is based on flow-shop type arrangement

2. Machines are fixed in position and operators and work pieces change places.

3. Casters are attached to the facilities and form a flexible line so that the line

layout can be changed according to the changing conditions.

4. A basic rule is piece – by- piece production in the process sequence.

5. No motion of an operator should be wasted. The movement of the operator

and number of finished products should be proportional.



12.1.3. Shape of a line

I-shape and U-shape lines are available. A U-shaped line is more favored since it has less

wasteful elements of the two.

12.2. Problems to be encountered with an

increased level of inventoryWhile keeping a certain level of inventory has some benefits such as being able to

deliver at short notice or other unexpected situations, it produces many problems as

well.

1. Extended lead time

2. Extended time within the factory

3. Eventually causing dead stock

4. Stagnant cash flow

12.3. Generation of inventory: Controllable

inventory and uncontrollable inventoryAlthough it may seem reasonable to keep a certain amount of inventory, generally

speaking, the higher the management level becomes, the less inventory should be

required.

Studying the reasons for having inventory frequently reveals that the inventory is

often only one result of some other incidence:

1. As a result of mass production or of production in large lost: Mass

production and mass consumption have almost come to an end.

2. As a result of an imbalance in the process capability

Lack of capability of the following process: Inventory due to poor line

balance. Elimination of the bottleneck processes

Concentration of parts / material in a certain area (process). Different start – up

timings result in waiting.

A point where a processing line diverges into several lines. Transportation –

waiting, since the amount that can be carried at one time is limited.

3. As a result of too much time required for setup: Stock which has become

stagnant before the start of operations; "single setup"

4. As a result of the operation being executed without planning and with lax

on-site control: Or as a result of the work being executed in lax fashion

5. As a result of preparing for an emergency: The minimum stock level as a

buffer against an emergency; to deal with the potential case of a shortage

caused by a defect. Improvement should be made by QC methods; to

deal with the potential case of a machine shutdown. Promotion of TPM

activities; to deal with the potential of a delayed delivery from a supplieror subcontractor. To get ready for potential corporate culture



6. Due to causes attributable to a particular corporate culture: Unable to

change the traditionally adopted production system

12.4. Lot production and flow production1. Lot production: A system in which products are produced in

predetermined units (lots)

Characteristics:

There needs to be as much transportation as the number of lots

More stagnant work in process

Longer lead times

2. Flow line production: A system in which each product is to be

assembled according to a predetermined sequence of a processes on at a

time within a set cycle time.

Characteristics: Transportation in possible during processing

Almost no work in process

Short lead times due to piece-by-piece production

Fig. 12.1. Example of implementation of FPC analysis for following workshop



Fig. 12.2. Comparison between two different line set-up production

Lot Production U-Shaped Line Production

4 4

D 6 D 2

O 3 O 3

` 1 1

14 10



Fig. 12.3. Comparison of Lead Times

12.5. How to form a U-shaped line12.5.1. Facility improvement

1. Arrange the pieces of production equipment in the order of theprocesses production facilities are to be arranged in the order of the

processes rather than the same kinds of facilities merely being put

together. Attach casters to a small machine or a work table.

2. Use a smaller machine of specialize a machine. For a good line

formation, a quicker finish by only one machine does not make any

sense.

3. Adopt piece-by-piece production. Finish products on a piece-by-

piece basis.

4. No downtime caused by mechanical problems

5. Zero defect of machine work

6. Remodeling the machines into ones with an automatic stop

mechanism

12.5.2. Improvement of human aspects

1. Assignment of multi-process work to multi-skilled operators. Use

the machine process time to do some work rather than idly waiting.

2. Work to be executed in the standing position. Move among the

machines.



3. Returning to the initial "start" position upon completion of the

operations (the U-shaped line system). The I-Shape line can also

used. However the I-shape necessitates an operator to return to the

initial position empty – handed.

4. Operation to be executed within a standard time (cycle time).Quickest job is not necessarily the best. Work is to be executed at a

constant rhythm to eliminate fatigue.

5. Observation of that standard (cycle ) time

12.6. Groundwork to materialize flow

production system1. Assignment of multi-processes. Difference between a system assigning multi -units of

equipment for each operator and that of assigning multi- processes to a single multi-

skilled operatorTable 12.1.

Multi- units per operator Multi- processes per operator

Operator capability

Machine layout

Machine

Single – skilled operator

Job shop type

Multi- propose machine

Multi- skilled operator

Flow shop type

Special – purpose machine

a) Points to realize the system of assigning multi- processes per operator Facilities with

casters(1) Have a smooth floor. Attach some counterweight to prevent the equipment

from toppling over. Use lockable casters.

(2) Elimination of waste from the current status of work. Operation improvement

by IE methods.

(3) Arrangement of the processes in a U-shape. Arrangement of the pieces of

equipment should show the inconvenience of large- sized machines

(4) Work to be performed in the standing position. Adjust the height of machines

and work tables so tables so that operators do not have to work in an unnatural

posture.

(5) Adoption of multi- skilled operators. Clarify the operations that each operator

can and cannot perform. Give necessary training so that the operator can

master new operations.

(6) Device to allow the operators to leave the machines (adoption of the automatic

stop system). After starting a machine, a operator perform other jobs while the

machine is processing the work piece.

Procedure to realize automation:

i. Automatic feeder, automatic stopping device

ii. Automatic take – out device for work pieces

iii. Automatic positioning device for work pieces



2. Determining standard operation

What is standard operation?

Work method to produce a conforming product in the same time and in the same

manner whoever may try it.

Three elements of standard work:

i. Cycle time

How to obtain cycle time

Number of pieces needed per day =Number of pieces needed per month

=10.056

= 457 pcsNumber of operating days 22

Cycle Time =Working hours

=480

= 63 secondsNumber of pieces needed per day 457

In the above example, the answers will be obtained on the assumption that the number of

pieces needed for a particular month is 10.056 (pcs), and the number of working days per

month, and the working per day being 22 (days) and 480 (minutes), respectively.

ii. Operation sequence

The process sequence is the processing or machining order.

The work sequence is a sequence followed by an operator while he/ she processes materials

to make a product. Decide the sequence of standard operation and let operators observe it.

iii. Standard work – in process

Determine the minimum amount of work in process to carry out work without disturbance.

Determine the amount of work in process to be kept beside the machine while processing.

(Precaution against an emergency).b) Standard operation instructions: See the diagram!

c) Observation of the operation standards.

Commitment across-the-board. Do not allow ant work areas to be exceptions;

make sure that there is across-the-board implementation

Strong will of the team leader. The team leader should display his own ideas about

manufacturing in his work area and work attitude.

Instructions should be clear to everyone; not only to the operators but to the

managers, visitors and operators from other sections

Improvements to the operation standards as necessary. Try to make work improvement continuous. The operation standards should not be left as they are

after being first made.

Holding meetings for discussions aiming at improvement. Regular meetings are

necessary for making a highly competent work place. Discussions should be made

on work improvement and to review present work methods.

12.7. Steps to build U-shaped lines1. Study the production volume. What is the monthly production volume?



Fig. 12.4. P-Q Analysis

2. Study parts production volume. Break down of parts and study of the

necessary quantity

Table 12.2. Sample of study part production volume

3. Process deployment of parts produced in-house. Preparation of Operation

Process Charts

a: S-L-M-Db: P-L-M-D

c: EL-L-D

S: stamping m/c L: Lathe M: Milling m/c P: Planer type milling m/c

D: Drilling m/c El: Endless grinder

4. Analysis of processing patterns

a: S

b: P L=M=D

c: El

5. Study of parts production volume by processing patterns

Deciding on the line



L- M- D a+b = 180+100=280 pieces

6. Measurement of operation time

Time study unit: second

S P EL L M D

AM/O 3 10 8 5

M/C 25 10 5

BM/O 10 10 8 5

M/c 10 10 10 10

CM/O 5 10 5

M/c 10

Table 12.3.

M/O: Time required for manual work by an Operator

M/C: Time required for Machining process

7. Designing standard operation

Fig.12.5.Study on design of standard operation

8. Improvement: Reduction in cycle time

Change the process sequence.

Change operation orders.

Use IE methods to improve a process where manual operation takes

much time. Try to reduce idle time if machining work takes much time.



Fig. 12.6. Standard Operation Organization Chart



Chapter Thirteen: Implementation of the JIT

Production System

13.1. Background of JIT manufacturing

systems13.1.1. Manufacturing that increases productivity even if the quantity of the

output decreases

1. The age in which large item small-scale production is a matter of course

In the 1990s, the Japanese manufacturing industry was confronted by theslump as a result of the burst of the economic bubble, which had been called

the Heisei Keiki. The conventional small item large-scale production moved

its bases to China, Southeast Asia, etc., where labor costs are cheap. This

resulted in importing the products manufactured in foreign countries.

In Japan, the market was flooded with products, giving consumers a free hand

in buying what they want. The traditional seller's market gradually changed to

a buyer's market. As a result, it became necessary to produce goods that

improve CS (customer satisfaction), and manufacturers were forced to

establish a flexible manufacturing system that copes with the so-called largeitem small-scale production.

2. QCD (Quality, Cost, Delivery) for which rigorousness is required

For manufacturing saleable goods during this time, it is necessary to improve

the international competitiveness by aiming to accomplish higher quality (Q),

lower cost (C), and shorter delivery time (D) while maintaining the

practical improvement planning for factories

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