chapter 7 research...

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CHAPTER 7

RESEARCH METHODOLOGY

7.1 RESEARCH DESIGN

The procedures for this study have been chosen to meet each of the

project objectives. The research is based on quantitative approach. The initial

step in this research is to understand the history of the lean manufacturing

concept and its different tools and techniques. It will be followed by the

analysis of applicability of such tools with the apparel production system.

Based on the literature, suitable lean manufacturing tools are identified .With

the support of some primary and secondary data, the research problem is

approached. Secondary data is collected from various other research works

which are related to lean manufacturing conducted on textile as well as other

manufacturing sectors. The primary data is generated specifically to address

the research problem, for which a series of case studies were conducted in

order to explore the implementation and application of certain lean tools in

the garment industry. Those lean tools are identified through Phase II of the

research. In Phase III, those identified lean tools will be implemented in

sewing section of the garment industry on four different products lines.

7.1.1 Phase I: Analysis of Secondary Sources

Systematic study of lean manufacturing concept and its various tools

and techniques through suitable research publications were done. Subsequently,

examining some, of the most applicable lean manufacturing tools and techniques

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were also done. In addition to this, suitable literature study was referred for

assembly layout, product line balancing, value chains in garment industry, work

in progress, Value stream mapping, skill demand, etc..

This objective was accomplished by an analysis of the following

secondary sources.

Literature: Textbooks, Trade Journals, and Scholarly Journals

related to lean manufacturing, industrial engineering, apparel

and textile industry

Professional Organizations, and Educational Institutions

Internet Search Engines

The results from Phase I are used to develop suitable lean tools

towards the project objectives.

7.1.2 Phase II: Brief survey of ABC Clothing Ltd

This proposed research is conducted at ABC Clothing Ltd

(company name is renamed as ABC to maintain the confidentiality as per the

company request), Chennai, India. This factory is very much interested to

implement Lean manufacturing tools on pilot basic. Based on the research

outcome, they decided to implement the same model replication for the entire

division. Basically, this is quantitative research where the researcher is a part

of the organization during the study.

To have a firsthand knowledge of the production flow and to be

familiar with the activities being performed at the floor shop, the researcher

went through the facility and identified each operation process involved from

raw material to finished goods. To address the current issues of the industry,

the researcher found out the standard operation time for each operation by

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using time study techniques. Subsequently the researcher analyzed the cycle

time, value added time, product defect level, Work in Progress (WIP), takt

time, number of operations, machine types, rate of production, etc..

7.1.3 Phase III: Implementation of Selected Lean Tool

In this phase, the researcher has identified the suitable lean tools

for four different product lines (product 1, product - 2, product - 3 and

product - 4) of the sewing section to address the mentioned issues. The

suitable tools would be implemented through revised value stream mapping

in a customized manner on all the product line. Finally the research outcome

is compared with the current level.

7.2 COMPANY AND PROCESS BACKGROUND

ABC is an apparel manufacturing company situated in Chennai,

India.This company is producing more than 80 % of knitted garments and less

than 20% of woven garment products .This is a 100% export oriented factory

getting regular business orders from UK,USA ,and Germany. Around 1500

employees are working in this firm towards the production related activities.

Due to competitive market, this firm intends to implement the lean

manufacturing principles in to their production environment.

7.3 PRODUCT SELECTION

The researcher has thoroughly studied various kind of products

produced at ABC. Some of the basic product lines are regularly manufactured

at this factory. With the consent of management, the research would be

conducted on four stable products lines (regular business order) at the sewing

section for which a separate team of persons are engaged for this research

work along with the researcher. The details of the product lines are as follows

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Table 7.1 Description about the garment products

S.No Product Type Fabric (Knitted/Woven) Product Code(referred throughout this research)

1 T.Shirt-Crew neck type

100 % Single jersey Knitted fabric

Product -1

2 Men’s Shirt-Basic model

100% plain woven fabric Product-2

3. Men’s Trouser-Waist band model


Product-3

4. Underwear-Basic model


Product-4

Product-1 Product-2

Product-3 Product-4

Figure 7.1 The photographic image of products selected for this research

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7.4 VALUE STREAM MAPPING

To create a current state Value Stream Map (VSM) for the product,

the plant is visited for three days in order to observe and collect the required

information. A map of the plant layout is obtained to further understand the

flow of materials within the plant. A process flow of each product line is

analyzed to gain a better understanding of the operation. The assessment is

done for four different major products lines which are constantly produced by

the company. For each of these styles, information such as machine set up

times, machine utilization, and inventory counts between the processes, takt

time (customer requirement) are collected for developing the value stream

map. The takt time of the product is calculated by dividing the demand of the

customer per day in each style by the number of operating hours per day.

Once the current state VSM for the products (product-1, product-2,

product-3 and product-4) is created various kinds of process wastages such as

causes of non value added time, sources of WIP, bottleneck operation, lead

time, operator idle time, unwanted movement of material in the process chain,

product defect level, machine setting time, and machine idle time etc.. are

analyzed for finding the real issue. After analyzing the issues, suitable lean

tools (Cellular Layout, Single piece flow, Kaizen, TPM, etc..) are identified

for addressing the issues. Subsequently the revised VSM for the products

(product-1, product-2, product-3 and product-4) is created.

The Value chain mapping for the products are done in sewing

section alone because the sewing section operator needs high skill towards the

product, machine and garment quality . And also the sewing process

determines the overall factory productivity as compared with other value

chains. The shipment failures due to sewing was analyzed at ABC and it is

depicted in the graph (Figure 7.2) below mentioned.

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Figure 7.2 Study on cause for shipment failure in last 5 years at ABC

From this pilot research it is understood that most of the shipment

failure is due to sewing section. So it is obvious that every garment

manufacturers are interested to make improvements at the sewing section

rather than other sections.

7.5 CURRENT STATE VALUE STREAM MAPPING

At ABC, Business planning department receives information

through Electronic Data Interchange (EDI) from the customer. In ABC,

mostly repeated styles (garment design) of garments are manufactured. The

order schedule is received on once in three months through EDI, the delivery

duration and mode of delivery are as per the buyer requirement. Most of the

customers of ABC expect higher product quality and on time shipment

delivery. Once the purchase order comes in, business planning department

estimates the date by which the factory can make it ready. The planning

department schedules it on weekly basis. Next, arrive at the day wise plan on

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the production level. Then this schedule is sent to the factory for further

execution. Business planning also includes making sure that enough raw

material is available and that there is with enough capacity on each unit. This

schedule should be feasible and balanced. This schedule on the operating side

become the basis to monitor day by day and week by week increments against

how well they are in accordance with the schedule. This schedule can then be

updated further on hourly basis or machine wise schedule, which is used to

push the order to the production facility.

All data for the current state map are collected according to the

approach recommended by Rother and Shook (1999) .The important data

such as inventory levels before each process, cycle times, number of workers

and the change over times are shown in current VSM. Initially for developing

current state VSM, the cycle time is calculated (by doing time and motion

study of sewing operations as per company practice). So that the researcher

can find the muda(process waste) in the existing practice. Subsequently

the researcher can find the scope for implementation of lean tools in the

current value stream mapping.

7.5.1 Customer Demand

On an average, the customers of ABC demand up to a total of

59,000 pieces from the product mix (Product-1, Product-2, Product-3 and

Product4). The expected production lead time for this business order is 10

days. The proposed pilot lean implementation is going to happen on this

business order. The distribution of the order quantities are as follows.

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From the above business order, for each combination around 2000

to 5000 pieces would be the average order from the customer. For shipment

ABC prefers two types of transport mode such as sea cargo or air cargo. This

shipment goes to the customer on weekly basis and the plant works 8 hours

per day.

7.5.2 Conducting Time Study

To calculate standard time for each operation, time study is

conducted in the shop floor. The Product assembling is done through PBS

(Progressive bundling system) layout. To do this, product lines such as

product-1, product-2, product-3, and product-4 are selected independently

because operations differ from style to style and it is difficult to correlate all

these operations of individual styles to get better results and a t least 15

cycles are conducted for each operation. After cycle time is derived from the

time study, it is added with the performance rating of operator (as per the

company’s existing standard) for getting the actual time for particular

operation. Finally the Personal Fatigue and Delay (PFD) component is added

with the actual time to get the Standard Allowable Minutes (SAM).

While conducting time study some parameters are kept fixed (for

example machine speed, stitches per inch, type of machine used etc.) to get

consistent results. The PFD factor is taken as 15% of total time (as followed

in the Industry).Similarly the average performance rating is taken 100% for

the ease of calculation only. The calculated SAM value for each section is

attached in Appendix 2.

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7.5.3 Takt Time Investigation

Takt time demonstrates the rate at which the customer buys the

product. Takt time reflects the frequency at which the products have to be

released from the manufacturer to meet the customer demand .Takt time is

calculated by dividing available working time per shift (in sec) with the

customer demand per shift.

Available WorkingTimeperShiftTAKT TimeCustomer Demand perShift

The proposed manufacturing firm has the available working time of

28800 seconds per shift and for the lead time of 10 days from date of

production commencement.

Product wise demand (Including SKU level)

Demand for product - 1=15000/10 days=1500 pcs/Shift

Demand for product - 2=20000/10 days=2000 Pcs/shift

Demand for product - 3=20000/10 days=2000Pcs/shift

Demand for Product - 4=12000/10 days=1200Pcs/shift

Takt time for product - 1=19.2 Sec



Takt time for product - 4=24 Sec

Every piece has to be manufactured as per the specified takt time.

For example, in every 19.2 seconds one piece of type product-1 should be

manufactured. The production rate more than 19.2 per piece would create

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delay in production delivery at the same time the production rate less than

19.2 seconds per piece would become waste in the form of over production.

According to this parameter, current VSM would be evaluated and the same

line new VSM would be created with the base of this takt time.

7.5.4 Current State Value Stream Mapping (VSM) for Product-1

The focus of this value stream mapping is towards Product-1.This

would be a 100 % cotton single jersey knitted T shirt. Fabric inspection and

fabric cutting process are common which would be done in a common usage

area irrespective of the product family. Sewing process starts with “front and

back matching” which would be done with the support of helpers in the

product line, so that any unevenness between the panels would be analyzed.

Once the screening process is completed the material goes to the “shoulder

joining operation” with five thread over lock sewing machine ,subsequently

“shoulder cut mark” would be created for easy sleeve attachment .The next

process is “shoulder top stitching” with cover seam . Once this process is

over “excess thread trimming operation” would be done on the semi finished

garments. The next stage of the operation is “preparation and attachment of

garment main label or brand label” with the support of Single needle lock

stitch sewing machine.

After this stage the material goes to “neck rib fabric attachment”

stage, which would be done through five thread over lock sewing machine

and then the “neck rib fold tacking” would be done with the single needle

lock stitch sewing machine. The next process is “attachment of neck rib fabric

panel” with the garment, which would be done through the single needle lock

stitch sewing machine.

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The next stage is to “attach the elastic tape” over the neck round.

Within this process, the first stage of operation is to “prepare the elastic tape”

with the support of helper in the product line, subsequently “attachment of

elastic tape” and “top stitching over the elastic tape” would be done through

single needle lock stitch sewing machine.

The next operation is to join the “Sleeve panel” with the body

panel, and before this operation the helpers would check whether any shade

variation is preset in between the panels. Subsequently “sleeve joining” is

done through five threads over lock sewing machine.

Next to this operation, the semi-finished material goes to “body

turn process” and then “side seaming” which would be done through the five

thread over lock sewing machine. Subsequently “body folding” would be

done through the helper. Then the material is taken to “hemming operation”

where single needle lock stitch sewing machine is used for “sleeve hemming”

and flat lock machine is used for “bottom hemming”. Then “security tack” is

made on the hemming portions with single needle lock stitch. Finally excess

thread would be trimmed out .The pictorial representation of current VSM for

the product-1 is as follows

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Figure 7.3 Current state VSM for Product -1

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7.5.5 Current state Value Stream mapping (VSM) for Product-2

The focus of this value stream mapping is towards Product-2. This

product would be 100 % cotton plain woven men’s shirt. Fabric inspection

and fabric cutting process are common which would be done in a common

usage area irrespective of the product family. Here the sewing process starts

with collar making operation, in which the first operation is known as

“pinning of collar profile” and then “run stitch the collar” subsequently “trim

out the collar profile” so that unevenness in the collar would be removed.

Next to this stage,” creasing the collar” and “attach the collar with collar

band” are done. Next course of action is to prepare the cuff making. Here

“cuff bias piece attachment” is carried out as first operation subsequently

“cuff hemming”, “run stitch over the cuff” and then “attachment of cuff to

sleeve portion” are done.

The next stage to this operation is to make the front section of the

garment, where in “front placket attachment”, “pocket making” and

“attachment over the front portion”, subsequently “attachment of brand label”

are done. Next to this stage “making the yoke portion” and “attachment of

yoke with back panel”, subsequently “shoulder attachment”, “sleeve

attachment”, “side seam making” and “bottom hemming operation” are

carried out. The pictorial representation of current VSM for the product-2 is

as follows

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Figure 7.4 Current state VSM for Product-2

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Figure 7.4 Current state VSM for Product-2 (Cotninued)

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product would be 100 % cotton single jersey knitted fabric based men’s

trousers. Fabric inspection and fabric cutting process are common which

would be done in a common usage area irrespective of the product family. It

is a casual wear having elastic waist band, and a strap to adjust the waist band

measurement according to the body measurement. This garment has single

solid color throughout its silhouette. Here the sewing process starts with

“sewing the side seam panels” after the “panel loading” to the sewing section.

Afterwards “top stitching on the side seam” is done. Subsequent to this

operation “bottom rib fabric attachment”, “top stitch over the fly assembly”,

“sewing on front and back rise” operations are done and then specific

“decorative stitches” are made over the front assembly and “in seam making”

would be done. Subsequent to this “invert out”, “elastic joining”, “waist band

preparation” , “attachment of waist band” and “top stich on waist band “

operations are carried out. After that “waist band strap end locking” and

“strap attachment” are the next stage of sewing operation. Finally “bar tack on

strap” and “crotch point” are made. The following Figure 7.5 indicates current

VSM for product- 3.

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Figure 7.5 Current state VSM for Product-3

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product would be 100 % cotton single jersey knitted fabric based inner wear.

This garment has single solid color as well as striped fabric throughout its

silhouette. Fabric inspection and fabric cutting process are common which

would be done in a common usage area irrespective of the product family.

The sewing process starts with “panel matching”, “attachment of label” at the

centre back position. After that “gusset attachment” is done. Subsequently

“binding attachment” is done on both the side of leg portions. Then “left side

seam attachment”, “binding attachment at the waist”, “close right side seam”

are done. After this stage, “secure the leg and waist”, “trimming”, “main

label preparation”, “main label attachment”, and “end line inspection” are

done. The following Figure 7.6 indicates current VSM for product-4

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Figure 7.6 Current state VSM forProduct-4

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7.6 FUTURE STAGE VALUE STREAM MAPPING

Describing and defining the future state map actually starts while

developing the current state map, where target areas for improvement start to

show up. Looking at the current state map of ABC (towards four selected

product line) several things stand out: (a) large inventories, (b) the huge

difference between the production lead-time and the value added time

(c) the process that happens on its own schedule (d) very low process ratio.

The goal of lean manufacturing is to aid in improving the satisfaction of

customer requirements through the whole value stream. In our current state

map we view inventory and lead-time as two equivalent things and try

to identify lean manufacturing tools to drive them down and create the ideal

state map. The basic philosophy is that more the inventory longer the lead

time, therefore the reduction of lead-time and inventory will expose and force

other kinds of wastes to surface, creating the opportunity for their removal.

On the map the proposed lean tools are highlighted .In addition to that the

Kaizen burst are highlighted at the improvement area.

Reducing inventory and attaining on-time completion will

automatically generate quality improvements. For example, reducing work in

process (WIP) will reduce the amount of defects to be repaired, which in turn

will improve quality. Also less WIP helps trace the root cause of a defect

easier. In order to address these issues, the researcher follows a systematic

procedure which tries to answers a set of questions. This allows one to come

up with an ideal future state map that will help in trying to eliminate the

different types of waste in the current manufacturing system at ABC. As per

literature reference, the appropriate lean tool such as cellular layout, single

piece flow, kaizen, TPM, supermarket and 5s are utilized to minimize the

WIP and process lead time. While developing the future states mapping these

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tools are systematically incorporated into the system.

7.6.1 Creating Cellular Layout for Product-1

The cellular layout is suggested in this research for achieving single

piece flow between the operations, cost effectiveness, operator skill

enhancement as well as to minimize the production lead time. In this

layout, there is no need for ordering or installing any new equipment,

instead it is just re-arranging the available machines inside the shop floor.

This single piece movement can also be done with the help of

automation (like slow speed conveyor and hanger system) but it may take

considerable time to install and also not suitable for frequent style changing

products as well as small order quantities. The cost for installation of this

automation is very high as well as time to train the employees about the

working principle of the system is tedious. Even after using the automation

system (slow speed conveyor or hanger), the operator’s multi-skilling cannot

be utilized because in this slow speed conveyor system, the operators are

allocated in a fixed manner. Since the conveyor rotates the pieces

automatically, the operator movement inside the product line is also

impossible which will affect the line balancing.

After lot of investigation and pilot study, the researcher found that

some of the operations in the existing VSM are not produced any value to the

product transformation. So systematically some of the operations were

removed from the existing VSM and few of the other operations were

combined together to minimize the SMV and operator involvement. The

quality checking points were removed from the preparatory, because the

operator who is producing garments should be aware of quality standards and

expected to work accordingly. After that from the current VSM, the

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operations such as “shoulder cut mark”, “thread cut”, “raw edge cut” are

removed completely. For creating the cellular layout, the entire assembly line

is converted into three modules (different cellular layouts) based on the

sewing process (operation needed to complete individual parts or semi-

finished garments). In the respective module few of the operation are

combined with each other. Finally new series of operations were formed for

all modules.

The first cellular layout is exclusively for producing shoulder

portion in the garment. There are seven sewing machines and five operators

are allotted in this module. Generally in the cellular layout the numbers of

machines are higher than the number of operators because more than one

machine will be allotted per operator which in turn helps to balance the flow

of material within the module. Since single piece flow (lean tool) principles are

followed in this module, the operators are not allowed to build up a WIP rather

they should change their operation immediately if WIP seems increasing. So in

this new layout, after feeding cut parts to this module, they will be converted

into final garment immediately because there is no scope for WIP storage

area. In this model, since each operator is responsible for their work, the

quality checkers are removed from the product line. So the final products are

audited randomly after assembly which will reduce the rework. The

recommended new layout is shown in Figure 7.7

The second cellular layout is exclusively for producing neck rib

fabric attachment. There are nine sewing machines and six operators are

allotted in this module. In this model, some of the operations in the existing

VSM are combined such as “neck join” and “thread cut” operations are

combined, “twill tape preparation”, “attachment of twill tape with neck” and

“top stitching over the twill tape” are combined ,finally “care label position

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marking” and “attachment of care label” are combined. The recommended

new layout is shown in Figure 7.7.

The third cellular layout is designed for sleeve attachment and

hemming operation. There are thirteen sewing machines and ten operators are

allotted in this module. Similar to the other sections, few of the operations are

combined together. For example “matching sleeve pairs” and “matching

sleeve with body” are combined ,then ”body turn”, “side seam” and “body

folding” are combined, next “bottom hem”, “sleeve hem”, and “hem tacking”

are combined, finally “thread cut”, “raw edge cut” and “body turn” are

combined.

A super market (lean tool) area would be allotted between the first

lay out to second layout, wherein buffer WIP (on an average fifteen pieces) is

temporally stored. This supermarket will balance the flow between the first

cell to second cell by keeping some buffer WIP. Accordingly, if the inventory

exceeds the supermarket buffer limit, immediately the previous cell

production should be stopped. In the same line similar super market is allotted

between second cell to third cell for maintaining the buffer WIP.

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Figure 7.7 Revised VSM for Product-1

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7.6.2 Creating Cellular Layout for Product-2


some of the operations in the existing VSM have not produced any value to the

product transformation. So systematically some of the operations are removed

from the existing VSM and few of the other operations are combined together

to minimize the SMV and operator involvement. The quality checking points

are removed from the preparatory, because the operator who is producing

garments should be aware of quality standards and expected to work

accordingly. For creating the cellular layout, the entire assembly line is

converted into five modules (different cellular layouts) based on the sewing

process (operation needed to complete individual parts or semi-finished

garments). In the respective module few of the operation are combined with

each other. Finally new series of operations are formed for all modules.

First cellular layout is exclusively created for collar production.

Here the operation “crease the collar band” is completely removed from the

current VSM and the operation “crease the collar” is combined with the “top

stich collar”. There are 12 sewing machines and 9 operators are allotted in this

module. As usual the numbers of operators are lesser than the number of

machines in this layout.

The second Layout is designed for preparing the shirt front portion,

such as front panel making, and pocket making. There are 12 sewing machines

and 10 operators are allotted in this module. In this model the operation

“crease the patch piece” is combined with the operation, “attach the patch

piece”.

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The third layout is exclusively for preparing sleeve assembly .The

operations involved in this module are “attach the placket to sleeve” ,”sleeve

placket diamond making”, “pleats making”, “hem attachment” and “attach the

front placket”. There are 14 sewing machines and 10 operators are allotted in

this module. As usual the number of machineries is higher than the number of

operators.

The Fourth layout is meant for preparing the cuff section. The

operations involved in this module are “attaching the bias piece” ,”hemming

the cuff”, “run stitch over the cuff”, “trim the cuff”, “turn the cuff” and “crease

the cuff bottom” . There are 15 sewing machines and 11 operators are allotted

in this module. As per the other sections one operation (turn the cuff) is

removed from the section.

The Fifth layout is used to assemble all the sections together. There

are 30 sewing machines and 22 operators are allotted in this module. In this

model the operation “join the shoulder” is combined with the operation “top

stitch over the shoulder “. In the respective place all other module outputs are

interfaced to make the complete garment.

A super market (lean tool) area would be allotted between the each

layout, wherein buffer WIP (on average fifteen pieces) is temporally stored.

This supermarket will balance the flow between the each cell by keeping

some buffer WIP. Accordingly, if the inventory exceeds the supermarket

buffer limit, immediately the previous cell production should be stopped. The

recommended new layout is shown in all the series of Figure 7.8

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(a)

Figure 7.8 Revised VSM forProduct-2

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(b)

Figure 7.8 Revised VSM for Product-2 (Continued)

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(c)

Figure 7.8 Revised VSM for Product-2 (Continued)

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Figure 7.8d Revised VSM for Product-2 (Continued)

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Figure 7.8e Revised VSM for Product-2 (Continued)

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7.6.3 Creating Cellular layout for Product-3


some of the operations in the existing VSM do not produce any value to the

product transformation. So systematically some of the operations are removed

from the existing VSM and few of the other operations are combined together

to minimize the SMV and operator involvement. The quality checking points

were removed from the preparatory, because the operator who is producing

garments should be aware of quality standards and expected to work

accordingly. For creating the cellular layout, the entire assembly line is

converted into three modules (different cellular layouts) based on the sewing

process (operation needed to complete individual parts or semi-finished

garments). In the respective module few of the operations are combined with

each other. Finally new series of operations were formed for all modules.

First, cellular layout is exclusively created for producing bottom

portion of the garment. Here the operations “sew the side seam panels” and

“top stitch on the side” are combined, then “top stitch on the front fly” and

“sew the front and back rise” are combined, then “decorative top stitch

making” and “decorative top stich attachment” are combined. There are 10

sewing machines and 8 operators are allotted in this module. As usual the

number of operator is lesser than the number of machines in the layout.

The second Layout is designed for producing the waist band

section. Here the operations “invert out operation” and “elastic join

operations” are combined. There are 10 sewing machines and 6 operators are

allotted in this module.

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The third layout is used to assemble all the sections together. Here

the operations “strap attachment to body”, “leg locking”, “bar tacking” are

done. There are 7 sewing machines and 6 operators are allotted in this

module.

A super market (lean tool) area is allotted between the first layout

to second layout, wherein buffer WIP (on an average fifteen pieces) is

temporally stored. This supermarket will balance the flow between the first

cell to second cell by keeping some buffer WIP. Accordingly if the inventory

exceeds the supermarket buffer limit, immediately the previous cell

production would be stopped. In the same line similar super market is allotted

between second cell to third cell for maintaining the buffer WIP. The

following Figure 7.9 indicates revised VSM for product- 3

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7.6.4 Creating cellular Layout for Product-4

The cellular layout is suggested in this research for achieving single

piece flow between the operations, cost effectiveness, operator skill

enhancement as well as to minimize the production lead time. In this

layout, there is no need for ordering or installing any new equipment, it is

just re-arranging the available machines inside the shop floor.After lot of

investigation and pilot study, the researcher found that some of the operations in

the existing VSM do not produce any value to the product transformation. So

systematically some of the operations are removed from the existing VSM

and few of the other operations are combined together to minimize the SMV

and operator involvement. The quality checking points are removed from the

preparatory, because the operator who is producing garments should be aware

of quality standards and expected to work accordingly. Only one cellular

layout is created for this assembly line. In this module few of the operations

are combined with each other. Finally new series of operations are formed for

this layout. Here the operations “loading”, “panel matching” and “trimming”

are removed completely from the existing VSM. Then the operations such as

“preparation of size label” and “attachment of size label” are combined,then

“attachment of gusset” and “over locking on the gusset” are combined, “close

the right side seam” and “trimming of extra threads” are combined, “main

label attachment” and “trimming of extra thread” are combined. There are 7

sewing machines and 6 operators are allotted in this module. As usual the

number of machineries is higher than the number of operators. The

recommended new layout is shown in Figure 7.10.

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7.7 WORK BALANCING BETWEEN OPERATORS

After defining work flow and creating cellular layout, the challenge

is division of work between operators. The work should be divided in such a

way that each operator should get equal work load. This will motivate

operators in their work as a result of which there is improvement in

productivity. To achieve this a few elements are considered as key elements

which are as follows

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1. All the sitting operations are converted into standing

operations or rotating machine chairs. This will help to travel

between machines so that one operator can handle multiple

machines within the cell. This is very difficult in case of

sitting operations.

2. Operators should be trained for at least three to four

operations of their respective work cells. This will help to

rotate operators between different operations.

3. To create pull system, the capacity of assembly is made

marginally higher than preparatory operations. In this way

every time when assembly operators are out of pieces,

everybody’s attention will go to preparatory section cells and

they will produce more for assembly operators.

4. The numbers of operators are less than the number of work

stations (machine) for rotating operators between different

operations and this helps in balancing the work load between

operators.

5. Finally, work is divided among operators of individual cells as

per SMV. This is a little bit difficult job because different

operations have different timings. So the worker who is

working in a job which takes less time should not build up

WIP, rather should change his (her) machine and do the next

consecutive operation. In this way, all the workers will rotate

inside the cell in zigzag pattern to balance the work. This way

of moving operators inside the work cell is called floating

balancing. The functioning of implemented cellular layout is

indicated in the following Figure 7.11.

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Stand up machine model Cellular layout model

Working practice inside the Cellular layout

Controlling WIP

Figure 7.11 Functioning of implemented cellular layout at ABC

The number of work stations and number or operators in different

work cells is shown in Table 7 .3 ; which shows that there are sufficient

work stations are available to rotate operators. When WIP increases, the

operator should immediately switch to the next operation and move forward.

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Table 7.3 Section wise numbers of machines and operator allocation in

revised VSM

Product category

Section No.of Machines

No.of Operators

Product-1

Shoulder module 7 5

Neck construction module 9 6

Sleeve module 13 10

Total 29 21

Product-2

Front section module 12 9

Collar module 12 10

Sleeve module 14 10

Cuff module 15 11

Finishing module 30 22

Total 73 62

Product-3

Bottom section module 10 8

Waist band Module 10 6

Finishing Module 7 6

Total 27 20

Product-4 Cellular Layout 9 8

7.8 CRITICAL OPERATION HANDLING

Any product consists of a set of different operations with

varying time and skill requirements in each stage. Even within the same

work cell some operations are critical in comparison to others. The

criticality of operation can be of different types; for example the job may

be critical being more time consuming than other jobs, or it may need

specific skill to complete it, or may need high attention because of customer

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complaints, or may be due to machine capacity etc. So after identifying the

critical operations, special attention should be given to them, because these

are the weakest links of the chain and if one link drops the whole chain may

be disturbed. In this research, the critical operations are identified for each

cell. For example, in product -2 shoulder joining operation in cell -1, neck rib

join in cell -2, and sleeve attachment in cell -3 are critical operations. So

while balancing a cell, extra care should be given to these operations. At the

same time, some extra operators should be trained for critical operations.

This will save from drastic production loss in absence of critical operators or

due to breakdown of machines for these operations.

7.9 CHALLENGES FACED WHILE IMPLEMENTING

CELLULAR LAYOUT

There are few challenges while implementing lean layout into the

sewing process because this layout is new to the people. The first challenge

is conversion of sitting operations to standing. Since operators are in th e

habitl of operating sitting machines and when these sitting machines are

converted into standing operator, machines, workers, lost their control on

pedal and it took some time to train them. Secondly for work balancing

purpose, one operator has to perform multiple operations by changing

machines, whereas operators don’t like to work on multiple machines

because they feel that management is overloading them with work.

The operators are convinced by saying that if people move around

the machine they will not get tired of the same operation and can work more

effectively as well as feel less tired. At the same time they will learn multiple

operations within their cell, which increases their skill and confidence.

Similarly, the balancing of a cell is as per the standard minute value (SMV),

so all the operators are given equal work load within their cell. Earlier to this,

the critical operators were blaming management and supervisors for

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allocating difficult operations to them. Now by the implementation of SMV

for work balancing, the problem of uneven work load is solved.

7.10 5s TOOL IMPLEMENTATION

5s principle is also introduced in sewing section for manufacturing

product-1, product-2, product-3 and product-4 in addition to the cellular

layout and single piece flow which is expected to increase the industrial

efficiency. The first step of 5s principle is to sort out the clutter from tables,

workstations and equipment .The procedure to remove items are based on the

utility of the equipment .The research team used the red tag tactic (Figure

7.11 Shows the model of red tag), to separate these items from the regular

production area. This consists of removing the rarely used items from the

work station by identifying them as items to remove from the workplace and

keep those items at the red tag area for temporary purpose.

Figure 7.12 Red tag model

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Table 7.4 Red tag classifications

Materials Usage frequency Where to place Daily Work station

Once in week Work area

Once in month Storage Area

Once in Year Ware house

Obsolete Sell/eliminate

The 5s program is implemented in the following five steps called

Sort, Set in order, Shine, Standardize, and Sustain. The detailed explanation

about 5s principles are explained in earlier chapter. We start by sorting items

based on the usage frequency and keep only what is needed to perform value-

added-activities and dispose of what is not needed. The classification where

items that are daily are kept in the workstation and others are kept at the red

tag area. Afterwards these red tag items are stored according to its usage, for

example the items that are used once a week is stored in the work area, once a

month in a storage place, once a year in the warehouse and obsolete items are

thrown away or sold.

The machines, where employees at work have a drawer, so that

essential items for the operations carried out in that machine can be kept.

However, as shown in the following pictures these drawers are full of

pointless and excessive items in existing stage. Therefore it is considered as

trash and eliminated

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Figure 7.13 Machine drawer before 5s implementation

The items in these drawers are sorted and the drawers are ordered

(step two of 5s) and cleaned (step three). After sorting the necessary and

unnecessary items, we concluded that in each workstation (inside the drawers)

only the following list of item should be stored:

Pack of needles

Small screwdriver

Big screwdriver

Scissors

Machine cleaning brush

needle fitting screw

Trimmer /clippers

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These are the most frequently used items and earlier employees

spent more time for seeking or asking the head responsible of the department

to bring them. The operator/module lead should make sure that the list of

above mentioned tools should be placed in the drawers. Drawers are now

organized as displayed in the following pictures.

Figure 7.14 Machine drawer after 5s implementation

As mentioned earlier, it was given an identification number for all

equipment’s on each workstation and also labeled with the respective

machines reference number, as the next pictures exemplify.

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Figure 7.15 Equipment with label-after 5s implementation

When sorting, some are only used on a weekly basis and therefore

it should be placed on the surroundings of the work area. Those items are an

oil flask, diversified screwdrivers and needle pack, tape dispensers or a fabric

softener.

Consequently, a shelf was placed near the work area with a space

labeled for each item. The head of the department is responsible for

monitoring every item is placed in the right place or is it ‘lost’ in the

production line. The following pictures illustrate the shelves made for

machine oil storage. For Each three modules, one oil storage point should be

there.

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Figure 7.16 Machine oil storage after 5s implementation

All these ensure that there are no needless movements or waiting

time for seeking a lost screwdriver or asking for a new needle.The tools being

labeled with the machine id number, the employee working in that machine is

now responsible for each tool and for letting everything in its place at the end

of a working day.

The next step is to set locations and limits for equipment and item

storage using indicators. Indicators such as lines and identification signs are

also placed to demark walkways and the different storage areas. For example,

storage locations of empty beams are marked off with lines on the floor,

which not only identified to the worker where to store these items but also

provided a limit to how many garments could be stored. Cleaning up and

organizing the area is an important goal that top management had in mind

when embarking on this 5s event. Cleaning of the floors and machines are

good practice. There is a regular cleaning schedule which should be followed

in the entire sewing section such every two hours the team members are

advised to clean the machine as well as the work place .The following Figure

7.17 indicates the cleaning practice followed by the team member.

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Cleaning the driving arrangements-5 Thread flat lock Machine

Cleaning the Machine bed 5Thread flat lock Machine

Cleaning the tension post at 5 thread flat lock Machine

Cleaning the cone stand

Figure 7.17 Cleaning the sewing machine parts and driving arrangements

The next step is to ensure that standard working practices are in

place and everyone in the area is trained in 5s principles and understood the

goals of the organization. In order to sustain the improvements made to the

production area where the 5s event had taken place, the company used a 5s

audit system. This audit system is used to ensure that 5s is continually carried

out within the area.

The last step of the 5s program is probably the most difficult step.

A self-discipline culture must be passed on to employees so that they maintain

a stabilized workplace in an ongoing process of continuous improvement. For

this, it was recommended that necessary training programs should be

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conducted so that employees are more conscious of the importance and

advantages of maintaining a clean workspace, also contributing for nurturing

teamwork bonds.

Another important action taken to sustain 5s is the weekly meeting

established during the least initial period of implementation .These weekly

meeting brought about suggestions for improving the process and work

environment for the people. At first, workers were reluctant to offer ideas, but

once some ideas were brought by management for encouragement, the ideas

came easier from the technicians and shop floor workers. In this pilot project,

the researcher received 15 suggestions from the operators for improving the

process and methods. These suggestions are documented and put on an action

sheet for implementation. For example there are various suggestion which

came from the shop floor worker for the product -1( T.shirt) regarding the

optimum pressure setting for the pressure bar, double feed dog setting, and

auto trimmer.

7.11 KAIZEN IMPLEMENTATION

Kaizen is defined as continuous development towards improving

the production efficiency. The principle behind this is that “a very large

number of small improvements are more effective in an organizational

environment than a few improvements of large value”. Mostly the Kaizen is

done with the support of shop floor team. In the sewing section the researcher

insisted kaizen in the form of work aid identification, method modification,

and operator skill improvement for improvement of productivity. Since there

would be enough effort done on method modification while creating the

future stage VSM (like removing many non-value added activates, combining

few operations), the researcher has given more importance to the work aid

identification.

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Work aid is the one which minimize the efforts involved in product

making. But identifying or developing the work aid towards the particular

operation is a tedious task .Here some of the work aids are identified/created

while making the products. The following table indicates various work aid

and its advantages to the some of the operations in products.

Table 7.5 Work aid implementation in process layout of Product-1

Folder type Operation description

SMVbefore

SMVafter

Sleeve Join 0.9996 0.56

Shoulder Join 0.3276 0.22

Side seam 0.8822 0.50

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SMVbefore

SMVafter

Top stitch side seam

0.911 0.75

Attach the yoke to back

0.418 0.35



SMVbefore

SMV after

Trouser Sew Side seam

panels

1.2 0.8

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SMVbefore

SMVafter

Left side seam attachment

0.2 0.12

7.12 TOTAL PRODUCTIVE MAINTENANCE (TPM)

IMPLEMENTATION

TPM is set of practice, which when implemented in an organization

as a whole gives the best utilization of machines with least disruption of

production. Machine breakdown is one of the major headaches for people

related to production. The reliability of the equipment on the shop floor is

very important because if any one of the machines is down the entire shop

floor productivity may be affected. The tool that takes care of these sudden

breakdowns and makes maintenance as well as production workers to

minimize these unplanned breakdowns is called total productive maintenance.

The goal of this is to eventually train the operators to look after the

equipment in their workstation (Nakajimi 1988). In this research the TPM

focus is to provide assignments like machine inspection, cleaning, lubrication,

needle replacement and basic machine setting tasks to the machine operator.

This frees up the technicians or maintenance team for productive

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maintenance, which includes higher value-added activities such as equipment

improvement, overhauls, training, etc. The key measure of TPM is machine

effectiveness, which includes availability, performance efficiency, and

Overall Equipment Effectiveness (OEE).

Availability =(loading time – down time)/ loading time

Performance efficiency = (net operating time – lost time) / net

operating time

OEE = availability * performance efficiency * quality rate

Accurate equipment records are essential in order to identify

potential problems (Hartmann1992).This TPM tool is in the revised VSM of

the product line-1(T-Shirt) suitably and the benefit of this implementation is

monitored subsequently. Few of the maintenance activities mentioned below,

which were earlier done by the maintenance team, would be assigned to the

machine operator/team members in the module.

Broken needle replacement

Foot pedal adjustment

Finger guard setting

Pressure bar setting

Thread tension adjustment

Bobbin case tension adjustment

Lubrication

For this task the particular sewing machine operators are trained

exclusively in the machine maintenance and trouble shooting for about 15

days in the above mentioned skill sets.

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7.13 SUMMARY

In this chapter research design is created towards the objective of

this research work at ABC. In addition to this value stream mapping (VSM) is

done for creating current state map towards the selected product line for

understanding the process waste as well as scope for implementation of lean

tools. For creating current level of VSM, the necessary basic data, such as

customer demand, cycle time, takt time and internal inventory are measured at

the shop of the selected product line. Subsequently lean tools such as cellular

layout, single piece flow, kaizen, 5s, TPM are implemented stage by stage in

all the products line. Challenges faced which implementing these lean tools

are also analyzed at this chapter. In addition to this issues related to product

line balancing, critical operation handling, layout setup, operators training are

discussed.

chapter 7 research...

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