Line balancing in Garments Industry

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 s

Prepared by:

Biplab Saha ID: 2009100400068

Md Mijanur Rahman ID: 2009100400105 Shayamal Krishna Debnath ID: 2009100400113

Md Tanvir Hyder ID: 2009100400118

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

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?

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.

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.

SMV calculation

Element description Obser

rating Obser time Basic Time Freq. Basic Time/Gmt Get bundle and sort parts 95 0.32 0.304 1/30 0.010

Match pocket flap to lining 105 0.11 0.1160.116 1/1 0.116

Sew round flap 100 0.48 0.480 1/1 0.480

Trim threads and turn out

flap 58 0.35 0.298 1/1 0.298

Top stitch flap 90 0.56 0.504 1/1 0.504

Close bundle and place

aside 110 0.23 0.253 1/30 0.008

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.

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%

Allowance and Calculation

Personal Needs and Fatigue = 7.5%

Other (Standing) = 4.0%

Machine Type Allowance % DNL

SNL/BH DNC/50L SNC/30L BS/BT Other

17.5 12.5 9.0 7.5 5.0 2.0

Production Planning

Load and capacity Planning

Successful planning requires knowledge of two variables to determine the time required to manufacture a contract.

Load – How much work we are putting on a section

Capacity – How much work a section is capable of

completing

In an ideal situation

>> Load = Capacity

Load and capacity

LOAD – Contract size x Work content

Capacity – The amount of work the factory or section is capable of doing.

The scheduling rule

Balance load and capacity

Arrange the programmed of work so that the load can

be achieved

Use common units – standard minutes

Balancing & Capacity

Total numbersAttendance hoursAbsenteeism

PerformanceLearning curveUncertainty about the equipment

Availability Reliability

Style Order qty SMV per Gmts Total SMV’s

Avon 10000 42 420000

Bar 8000 30 240000

Clyde 24000 20 480000

Dee 12000 65 780000

a) Calculate the average weekly load in standard minutes

1920000sm’s/13 weeks = 147692 SM’s

b) If the factory employs 80 operators, has 4% absenteeism, works a 40

hour week, has a efficiency of 85%,

c) what is the weekly capacity in standard minutes?

80*40*0.96*0.85=156672sm’s

d) His the Factory sufficient capacity to meet the plan?

I think its Yes

The pre Production plan for the next 13 week season has provided the following information

Pitch Time

Reference value for synchronization in the division of labor is called Pitch Time (PT) Pitch Time provides average time allotted

to each worker.

PITCH DIAGRAM

Pitch Diagram in the form of Bar Graph

Work

Allotment

Time

How to reduce the number of

bottleneck processes

(1) Investigate the relation between the bottleneck process and its previous and subsequent processes to correct the line organization

(2) Investigate whether it is possible to further divide the process.

(3) Conduct the motion study for work improvement.

(4) Make improvements to equipment, jig and tools.

(5) Mechanize the manual work.

(6) Change the positions of workers.

(7) Investigate the modification to the machining specifications (8) Make it a rule to lend the worker in charge of the bottleneck process a helping hand

Control limit

The contributions and incessant efforts of all the group members to complete the project report are highly appreciative The challenging environment in 21st century demands that textile education should be meaningful and responsive to develop a mechanism to produce dynamic and technically competitive human resource in order to meet the challenges of the global world Right and effective strategies needs to be adopted for affecting productivity with quality improvements in textile education thereby making it relevant and useful not only for the sustained growth and development of the textile institutes but also in serving the societies in a progressive way.

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