a session on work study

BYSANDEEP PRASAD

M.F.TECH , NIFT , INDIA

04/18/2023

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A session on INDUSTRIAL ENGINEERING

Work Study - Definition

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Work Study is the systematic examination of the methods of carrying out activities such as to improve the effective use of resources and to set up standards of performance for the activities carried out.

Work Study and its tools

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WORKSTUDY

Work Measuremen

t

Method Study

Time it takes to do the job

Best way to do the job

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Work Content (Total time of a job)

A

B

C

Total time of

operation under

existing conditions Total

ineffective time

Basic work content

Basic work content of product and / or operation

A : Work content added by poor product design or materials utilization

B : Work content added by inefficient methods of manufacturing or operation(Poor layout, material handling, &WIP)

C :: Ineffective time resulting from human resources contribution

(Absenteeism,poor workmanship,accidents)

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Productivity is:

The Ratio between OUTPUT and INPUT

OUTPUT

INPUT

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Productivity Caln.

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Factory Example

Factory 1

Produced 500 dresses per day with 50 operators

Therefore 1 operator makes 10 dresses per day

The Productivity ratio is 1 person to 10 dresses

Factory 2

Produced 675 dresses per day with 75 operators.

Therefore 1 operator makes 9 dresses per day.

The Productivity ratio is 1 person to 9 dresses

More productiv

e

Production higher

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Method Study - Definition

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The systematic recording and critical examination of ways of doing things in order to make improvements is known as Method Study.

Founder : Frank Gilbreth Developed further by : Professor Barnes.

Method Study - Benefits

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• Better understanding of work performed• Improved operator performance• More safety & less risks from hazards for health and assets.• Less operator fatigue.

Method Study - Steps

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• ‘SREDDIM’ ( Pneumonic) – Select work to be studied– Record from observation of all relevant facts.– Examine critically(with help from your friends)– Develop the best method and workplace.– Define a new method which gives best economic

returns.– Install a standard practice.– Maintain by regular routine checks.

Work Measurement - Definition

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Work Measurement is the application of techniques & designs to establish the time for a qualified Worker to carry out a task at a defined rate of working.

Session 2

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Tools of Work Measurement

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‘TRAAPU’Activity SamplingUse of Cycle ChecksRatingAllowancesTime StudyProduction Study


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a large number of observations are made over a period of time of one group of machines, processes or workers.

Cycle Checks – Pick Align Position Sew Dispose Pick

Tools of Work Measurement- Time Study

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Purpose of Time Study :• Establish Standard Times• Rate Operator performance• Gain information to calculate overall production capabilities and Data for capacity planning.• Establish the total Work content of finished goods.

Tools of Work Measurement(Contd.)

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• Types of Stop Watches :– Flyback watches

• As the user presses the top knob , the clock hands return to zero and begins timing for the next element.

– Split hand watches• While one hand flies back when the top knob is

pressed,the other is stopped.After the second hand has been read,a side knob , on the top left edge of the watch is pressed and this cause the stopped hand to fly back to join back the other hand which has been moving around the usual way.

Session 3

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Allowances

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Rating / Basic Time/ Standard Time

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Observed Time X Observed Rating = Basic TimeStandard Rating

e.g. 1.20 X 90= 1.08100

Some allowances , usually 12.5 % ( PFD allowance ) is

added to the Basic time to get Standard Time .

Pls Note :

PFD : Personal , Fatigue & Delay allowance.

Standard Time Calcn.

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Determination of sample size of Cycle Checks

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* For 95.45 confidence level and a margin of error of +/- 5 %

Efficiency Calcn

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PMTS(Predetermined motion time systems) /MTM / GSD

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PMTS : PMT Systems are methods of setting basic times for doing basic human activities necessary for carrying out a job or task.

MTM : ( Method Time Measurement) It defines –

eight hand movements , nine foot and trunk movements & two eye movements

For each movement , a time value is assigned.

GSD (General Sewing Data)

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FLOW PROCESS CHARTS

Operation,It denotes change in the part or product

Inspection(For quantity only)

Inspection(For quality only)

Transportation

Permanent Storage

Temporary Storage

Combined activities( in this case operation and inspection)

Process chart symbol

OPERATION

Indicates the main steps in a process, method or

procedure. Usually the part, material or product

concerned is modified or charge during the operation

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INSPECTIONIndicates an inspection for quality and / or check for quality


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TEMPORARY STORAGE OR DELAY

Indicates a delay in the sequence of events: for example,

work waiting between consecutive operations, or any

object laid aside temporarily without record until required

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TRANSPORTATION

Indicates the movement of workers, materials or

equipment from place to place

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PERMAMENT STORAGE

Indicates a controlled storage in which material is

received into or issued from a store under some form of

authorization, or an item is retained for reference

purposes

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COMBINED ACTIVITIES

When it is desired to show activities performed at the

same time or by the same operative at the same

workstation, the symbols for those activities are

combined, e.g. the circle within the square represents a

combined operation and inspection.

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Two-handed Process Chart

The two-handed process chart is a process chart in

which the activities of a workers hands (or limbs) are

recorded in their relationship to one another

The two-handed process chart is a specialized form of

process chart because it shows the two hands (and

sometimes the feet) of the operators moving or static in

relation to one another, usually in relation to a time scale.

The advantage of incorporating a time scale in the chart

form is that the symbols for what the two hands are doing

at any given moment are brought opposite each other.

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Generally used for repetitive operations, when one cycle

of the work is to be recorded. Recording is carried out in

more detail than is normal flow charts.

The symbols used has slightly different meaning :

1. Operation : Is used for the activities of grasp, position,

use, release, etc. of a tool, component or material.

2. Transport : Is used to represent the movement of the

hand (or limb) to or from the work, a tool or material.

3. Delay : Is used to denote time during which the hand or

limb being charted is idle (although the others may be in

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4. Hold : I s used to represent the act iv i ty of hold ing the work, a tool or mater ia l i .e , when the hand being charted is hold ing something.

5. Inspection : examinat ion of a piece .

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The very act of making the chart enables the

work study man to gain an int imate knowledge

of the deta i ls of the job, and the chart i tse l f

enables him to study each e lement of the job

by i tse l f and in re lat ion to other e lements .

From this study improvements ideas are

developed.

These ideas should be ·writ ten down in chart

form when they occur.

The best method is general ly that which

requires the fewest movements .


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EXAMINE cr it ica l ly

An examinat ion of the deta i ls of the or iginal

method, us ing the quest ioning technique, at

once raises certa in points .

1) Why is i t necessary to hold the tube in the

j ig?

2) Why cannot the tube be notched whi le i t is

being rotated instead of the r ight hand

having to wait?

3) Why does the tube have to be taken out of

the j ig to break i t?

4) Why pick up and put down the fi le at the

end of each cycle? Can i t not be held?


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Two-handed Process ChartSome points on compiling charts are worth mentioning :

Study the operation cycle a few times before starting to

record

Chart one hand at a time

Do not record more than a few symbols at a time

The action of picking up or grasping a fresh part at the

beginning of a cycle of work is a good point at which to

state the record.

Start with the hand that handles the part first or the

hand that does the most work. The exact point of

starting is not really important, as the complete cycle

will eventually come round to it again, but the point

chosen must be definite.

Add in the second column the kinds of work done by the

other hand.

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Procedure flow chart

Process charts can be used in the office but it is more

useful to use a variation of the process chart known as a

procedure flowchart – this is in effect a document-type

flow process chart, since it charts the progress of a

document or series of documents through a procedure

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Symbols used in Procedure flow chart

Connector

Start / End

Process Step

Decision

Identify the responsible

Identify the information

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Symbols used in Procedure flow chart

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String Diagram

The string diagram is a scale plan or model on which a

thread is used to trace and measure the path of workers,

material or equipment during a specified sequence of

events. One technique for recording and examining this form of

activity is the string diagram. It is one of the simplest of

the techniques of method study and one of the most

useful.

String diagram should be drawn correctly to scale.04/18/2023

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Str ing diagram is a useful tool for recording

the distance traversed by a worker in the

working area.

Construct ion of the diagram involves the

fo l lowing steps:Step 1: Preparing a study sheet .

The worker under consideration is followed and the different points in the working areas he covers are noted down in a study sheet.

The recording of movements is continued till a

representative picture of the workers movements is

obtained.

This implies that the movements are noted down for

enough number of cycles so as to capture the actual

work cycle in terms of the journey made by the worker

with their respective frequencies.

String Diagram

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Step 2: Drawing a scale plan of the working

area. Once the study sheet is prepared, the

next step is to draw a scale plan of the working

area.

Machines, benches, stores and all other points at

which calls are made by the worker are drawn to the

scale together with doorways, pillars etc. that affect the

paths of movements.

The plan is then attached to a softwood or composition

board and pins are driven firmly at every stopping

point.

The heads of the pins are allowed to stay clear of the

surface by about 1cm. Pins are also driven in at all

turning points on the route.

String Diagram

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STEP 3: Combining Steps 1 and 2 to

construct the fi nal d iagram.

In the final Step, a measured length of thread is

taken and tied round the pin at the starting point of

the movements.

It is then led around the pins at the other points of

call in the order noted in the study sheet till all the

movements as noted in Step 1 have been covered .

The resulting diagram is the string diagram.

String Diagram

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String Diagram

AB

C

D

E

F GH

I

J

KL

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I t should be apparent that the str ing diagram

is s imi lar to the fl ow diagram. While one is

used for recording movements of materia ls , the

other is used for recording movements of

workers . Most often these tools are used

together-with the fl ow process chart in order to

give a better picture. The essent ia l d iff erence

between these two diagrams are:

a) I t is necessary that the str ing diagrams be

drawn correct ly to scale . The ordinary fl ow

diagram can be drawn approximately to scale

with important distances marked on i t so that

scal ing off is unnecessary.

String Diagram

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b) A fl ow diagram would look bulky i f too many

to and fro movements between diff erent points

are there; however, such movements wi l l not

aff ect a str ing diagram.

String Diagram

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String diagram

The examination of the diagram and the development of

the new layout can now proceed on the same lines as

with a flow diagram, with templates being used and the

pins and templates can be preformed with a minimum

movement between them.

This can be ascertained by leading the thread around the

pins in their new positions, starting form the same point

and following the same sequence. When the thread has

been led around all the points covered by the study, the

length left over can again be measured.

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The diff erence in length between this and the

thread lef t over from the or iginal study wi l l

represent the reduct ion in distance traveled as

a result of the improved layout .

The process may have to be repeated several

t imes unt i l the best poss ible layout ( i .e . the

layout with which the minimum length of thread

is used) is achieved.

String diagram

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Travel chart

A travel chart is a tabular record for presenting

quantitative data about the movements of workers,

materials or equipment between any number of places

over any given period of time.

.

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Travel chart

Layout sketch of office showing location of stations

1

2 3

4

5 6

7

8

9

10

Workstations

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Travel Chart

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Multiple activity chart

A multiple activity chart is a chart on which the activities

of more than one subject (worker, machine or item of

equipment) are each recorded on a common time scale to

show their interrelationship

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Multiple activity chart is a useful recording

tool for s i tuat ions where the work involves

interact ions of d iff erent subjects . One or more

workers looking after diff erent machines or a

group of workers working on loading materia ls

at one point and dumping the same at a

diff erent point are some examples where th is

type of chart can be used eff ect ively.


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The fundamental d iff erence between this tool

and the other charts descr ibed in the previous

sect ion are as fo l lows:

a) In mult ip le act iv i ty chart a t ime scale is

used. No such t ime scales are used in the

charts descr ibed ear l ier in th is chapter.


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b) Mult ip le act iv i ty charts can be used equal ly

eff ect ively even i f there is no movement of

workers involved in the work under

considerat ion. The pr imary focus of th is chart ,

for s i tuat ions where the workers are moving as

a part of their work, is to ident i fy the id le t ime

on the part of e i ther the workers or the

machines. The focus of other charts descr ibed

so far were pr imari ly to ident i fy excess

distances traversed by the worker, which is

only indirect ly re lated to the t ime.


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This is used when i t is necessary to record on

one chart the act iv i t ies of one subject in

re lat ion to another.

By using separate vert ica l co lumns, or bars ,

to represent the act ivates of d iff erent

operat ives or machines against a common t ime

scale , the chart shows very c lear ly periods of

id leness on the part of an of the subjects

during the process . A study of the chart often

makes i t poss ible to rearrange these act iv i t ies

so that such ineff ect ive t ime is reduced .


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The mult ip le act iv i ty chart is extremely

useful in organiz ing teams of operators on

mass-product ion work, and also on

maintenance work when expensive plant

cannot be a l lowed to remain id le longer.

I t can a lso be used to determine the number

of machines which an operator should be able

to look after.


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Multiple activity chartTeam work : Inspection of catalyst in a converter (original)

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Multiple activity chartTeam work : Inspection of catalyst in a converter (improved)

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Layout

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• The best layout of a factory depends on the following factors :– The minimum length of route for mechanical

transportation.– The machinery location.– The method of transportation.– The production system involved.– The type of garment being manufactured.– The shape of the building and the number of its floors.– Safety requirements eg. For fire exits etc.

Layout(Contd.)

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Session 4

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Principles of Motion Economy

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MISS CHURN

M The extent of a movement should be kept to a minimum.

I The workplace should be adjusted to to the individual.

S Ideally one useful movement should be matched by another , so that they are symmetrical.

S Where possible , movements of the arms and of the other parts of the body should be simultaneous.

Principles of Motion Economy(Contd.)

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C Movements should be continuous and not jerky.

H The tools and parts should always be in the same place.In this way the method becomes habitual.

U Unrestricted movement makes the work less tiring.Work aids eg. Edge Guides can be a good example where the operator has to exert less control.

R Rhythmic movements is a natural movement , which makes the work less stressful and more productive.

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Sr. No. Operation M/C Used SMV hourly output(pcs) output in 8 hrs target M/c reqd1 Shoulder Join 4 th O/L 0.7 90 720 800 12 Sleeve Join 4 th O/L 1.5 40 320 800 33 Collar Attach SNLS 1.7 36 288 800 34 Collar Finish SNLS 2.0 30 240 800 35 Side seam close 4 th O/L 2.3 26 206 800 46 Sleeve Hem F/L 3.0 20 160 800 57 Bottom Hem F/L 2.3 26 206 800 4

13.5 23

SMV Means Standard Minute Value( It is calculated by adding the PFD allowances to the Basic Minutes )

Session 5

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Garment Engineering

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Definition :Garment engineering is a questioning technique, it questions each process/operation of the total work content and by using innovative methods of construction and technology so that we can reduce the work content and increase profitability.

Garment Engineering ( Contd.)

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where should it begin?It should start in the design cell, because if we do this at the production stage it’s too late, garment engineering directly affects the costing so it must be done at the development stage.


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Who should be involved?Designers, Sample room manager, Industrial

Engineering department and production management all of them should give their input from cutting to finishing.


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Steps for Garment Engineering - ‘CRAAFT’1. CHOOSE – the operation / process to be studied by making sure it is worthwhile spending time to improve it.2. RECORD-every detail about the job, even if it seems to have no effect on the method; sometimes the most minor detail can make a huge difference in the Garment Engineering process.

Garment Engineering (Contd.)

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3. ASSESS - all the details by asking WHY? WHERE? WHAT? WHO? 4. ALTERNATIVES- Consider all the alternatives available for improvement and DEVELOP the most suitable.5. FIT - best alternative and make sure it is understood by all concerned.6. TAKE CARE- of the new technique once it is installed successfully by continually checking that it is still being performed correctly.

Session 6

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Garment Engineering(Contd.)

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• Key areas for analysis1. Seam types – Various seam types should be analysed and considered to simplify/reduce the work.

2. Stitch types- Explore various options in terms of seam types what is possible just by changing the seam type. For example replace lock stitches by chain stitch in case of Multineedle seams.

3. Machine types- Optimum use of technology to maximize , look in to machine type, bed shapes and automation that’s possible.

4. Attachments – Attachment can help immensely in simplifying and reducing the work content, sometime operations can be combined using attachments to increase line balancing efficiency.

Garment Engineering (Contd.)

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Garment Engineering(Contd.)

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5. Special work aids- Special work aids can be designed to simplify/reduce the work content.

This is a Venturi Tube which is uses air pressure to pick up the labels, so there is no fiddling around while picking up the labels.


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6. Fabric consumption- Fabric being 70% of the garment cost is vitally important to monitor and if theengineering is done properly we can certainly expect to save fabric or reduce consumptions.7. Cutting- how should it be done- we do not have Tailors now, we have operators instead and they should beworking with clippers in their hands8. Finishing- Finishing is an area which is generally overstaffed being the last link of the value chain all theproblems from the previous stages have to be sorted out here, Garment Engineering can reduce considerable manpower from this area.

Some Examples of GE

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Qualities of a Work Study officer

Minimum standard of education. Should be given practical exposure Should have an inventive mind. Should be able to have good human

relations Sincerity and honesty. Enthusiasm & Tactfulness Interest in and sympathy with

people. Good appearance with Self

Confidence.

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Responsibilities of work study Department

Performance and discipline

Garment breakdowns

and operation sequences

Standard times Proper methods

Line balancing and line layouts

Be familiar with the latest

equipment

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Responsibilities of work study Department

Garment engineering.

Keep management

informed .

All productivity related issues.

Familiar with productivity

systems

Monitoring of factory lost

time.

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THANK YOU

a session on work study

Documents

tools of work measurementcontd

method study bysandeep

best method

period of time

new method

jobabctotal time of

improved operator performance

operator fatigue