Line balancing in Garments Industry

Prepared by:
Biplab Saha ID: 2009100400068
Md. Mijanur Rahman ID: 2009100400105
Shayamal Krishna Debnath ID: 2009100400113
Md. Tanvir Hyder ID: 2009100400118
Supervised by:
Minhaz Ahmed
Lecturer
Department of Textile Engineering
Introduction
Line and work cell balancing is an effective tool to improve the throughput of
assembly lines and work cells while reducing manpower requirements and
costs. Assembly Line Balancing or simply Line Balancing (LB) is the problem
of assigning operations to workstations along an assembly line, in such a
way that the assignment be optimal in some sense. LB has been an
optimization problem of significant industrial importance: the efficiency
difference between an optimal and a sub-optimal assignment can yield
economies (or waste) reaching millions of dollars per year.
LB is a classic Operations Research (OR) optimization problem, having been
tackled by OR over several decades. Many algorithms have been proposed
for the problem. Yet despite the practical importance of the problem, and the
OR efforts that have been made to tackle it, little commercially available
software is available to help industry in optimizing their lines.
LINE BALANCING (Process Organization)
The Line Balancing is “to design a smooth production flow by
allotting processes to workers so as to allow each worker to
complete the allotted workload within an even time”
LINE BALANCING (Process Organization)
It is a system where we meet the production
expectations and we can find the same amount of

work in process in every operation at any point in
the day.
Reasons to have balance the production
line
(1) Keeping inventory costs low results in higher net
income
(2) Keeping normal inventory levels lets the operator
work all day long giving him/her the opportunity to
earn more money by increasing his/her
efficiency
(3) Keeping the line balanced let’s the supervisors
improve other areas because they can use their
time better
(4) Balanced production keeps prices low which turns
into repeat sales
(5) Balanced production means better production
planning.
Balancing Method
The most basic methods are the Time Study,
Bottle Neck Process Theory and Data Collection and
Analysis.
How do we start balancing the production
line?
Well we can start by determining how many operators for
each operation are needed for a determined level of
production. After this we need to determine how much
WIP we need to anticipate production problems.
Recommended WIP is 1-hour inventory level for each
operation. A good range would be from 30 min to 120 min
inventory level.

There are 3 rules for balancing
(1) Have at least ½ hour of WIP for each
operation
(2) Solve problems before they become any
larger
(3) Meet production goals by keeping every
operator working at their maximum capacity
Work In Process (WIP)
What is WIP?
WIP is made up of all garments and their
parts that are not completely finished.
How can we manage WIP?
(1) Production planning
(2) Trims control
(3) Production Build-up
(4) Balancing
(5) Cut Flow Control
Balancing Matrix
LOW
WIP
HIGH
OUT PUT
LOW
Time Study
What is time study?
Time study is a work measurement technique
for recording the time of performing a certain
specific job or its element carried out under
specific condition and for analyzing the data
so as to obtain the time necessary for an

operator to carry out at a defined rate of
performance
Time study is a method of direct observation. A trained
observer watches the job and records data as the job is
being performed over a number of cycles.
Time study equipment
the stop watch in general, two types of watch are used for time
study.
Fly back
Continuous
These watches may be used any of the following time scales
Seconds
Decimal minutes
Decimal hours
Time Study
SMV
SMV – time that is allowed to perform the job satisfactory.
SMV = Basic time + Allowances
Standard Minute Value
SMV = B.T + Allowances
Basic Time
The basic time for the operation is found by
applying concept of rating to relate the observed
to that of a standard place of working.
Calculated as follows:
Basic time = observed time * observed rating
100
(BT = Observed time * Observed Rating = A constant)
100
Example

Rating 50 75 100 125
Observed time 1.20.80.60.5
Basic Time 1.2*50 0.8*75 0.6*100 0.5*125
100 100 100 100
= 0.6 0.6 0.6 0.6

SMV calculation
Element description
Element description
Obser
Obser
rating
rating
Obser.
Obser.
time
time
Basic
Basic
Time
Time
Freq.
Freq.
Basic
Basic
Time/Gmt
Time/Gmt
Get bundle and sort parts
Get bundle and sort parts
95

95
0.32
0.32
0.304
0.304
1/30
1/30
0.010
0.010
Match pocket flap to lining
Match pocket flap to lining
105
105
0.11
0.11
0.116
0.116
1/1
1/1
0.116
0.116
Sew round flap
Sew round flap
100
100
0.48
0.48
0.480
0.480
1/1

1/1
0.480
0.480
Trim threads and turn out
Trim threads and turn out
flap
flap
58
58
0.35
0.35
0.298
0.298
1/1
1/1
0.298
0.298
Top stitch flap
Top stitch flap
90
90
0.56
0.56
0.504
0.504
1/1
1/1
0.504
0.504
Close bundle and place

Close bundle and place
aside
aside
110
110
0.23
0.23
0.253
0.253
1/30
1/30
0.008
0.008
Total
Total
1.416
1.416
Total basic time/garment (brought forward) 1.416
Add machine attention allowances 7%
7% of (0.480 + 0.504) = 0.07 x 0.984 = 0.069 0.069
Basic time + MAA (1.416 + 0.069) 1.485
Add personal needs and relaxation allowances 14%
14% of 1.485 = 0.14 x 1.485 = 0.208 0.028
Standard minute Value (SMV) = Basic time + all allowances
= 1.485 + 0.208 = 1.693 (SMV)
Operators Performance rating
Listed bellow are the twenty levels of
performance used in the rating process. You
will note that each definition has a
corresponding percentage figure. It is this

figure that is used in leveling.
Production Calculation
Target = 60
(individual) SMV
Line Target = Actual Minutes
Total M/C SMV
Actual Minutes = No. of M/C operators X working mints
efficiency x present %
Efficiency and Performance
Calculations
Efficiency = Earned Minutes x 100
(of individual) Available minutes
Earned minutes = No. of produced pieces X SMV of that activity
Available Minutes = Working Minutes
Example 1
An operator worked for 8 hours on an activity of
having a SMV of 5. She produced 82 pieces of that
activity. What was her efficiency?
Efficiency = 82 x 5 x 100 = 85.42%
8 x 60
Example 2.
An operator worked for 9 hours on activity of having SMV of
1.21 & 0.80. She produced 195 & 250 of those activities
respectively. What was her efficiency?
Efficiency = 195 x 1.21 + 250 x 0.80 x 100
9 x 60
= 80.66%
Example 3
An operator worked for 8 hours on an activity of
having a SMV of 5. She produced 82 pieces of

that activity. She had 40 minutes of stoppage
time due to machine breakdown & power failure.
What was her performance?
Performance = 82 * 5 * 100
( 8 * 60) – 40
= 93.18%