assembly vs modular manufacturing

Assembly Line Vs. Modular System “A comparison on reality grounds”

Manoj TiwariUser 1

Introduction- A lot has been written and discussed about various

manufacturing systems in apparel industry. Different experts have different

opinions on advantages and disadvantages of one system on another. But

most of the times we miss to cover all aspects altogether and thus unable to

realize or visualize the actual picture, which takes shape after a break

through change in the manufacturing set-up. Most of the times these big

decisions are taken without a proper analysis and it results in big disasters.

This article is an effort to have a comparison of Assemble Line to Modular

Line on reality grounds, which will help us in opting the suitable

manufacturing system for the plant.

Money matters more and it plays much more important role when you are

dealing in apparel sector, as competition is growing faster resulting in

everyday shrinking margins.

For any business below factors play vital roles-

1. Man

2. Machinery

3. Space

The ultimate objective is to have the best utilization of above all, so that the

profits can be maximized.


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A good amount of literature, experts’ comments and consultants’ views

advocating the benefits of Modular manufacturing are available. So first let’s

have a crux of that-

Modular manufacturing is a type of Flexible manufacturing systems,

which provides Faster and efficient through put and better balancing of

work by keeping lower WIP and needing less space.

The Modular system enhances multi skill development of operators,

which helps in quick response to style change with achieving quality

standards.

Apart from above, it increases team spirit which helps organization in

improving work environment.

Now let’s try to have a detailed comparison of Assembly line system to the

Modular on ground realities.

(For comparison and calculations the product taken is 5- Pocket Denim

Jean, Assumed SAM-14.0 min. /Garment)

Type of Manpower required

Salary/ Month (Indian Rs.)*

Requirement for Assembly Line (Nos.)

Requirement for Modular System (Nos.)

Cost/Month (Indian Rs.) for Assembly Line

Cost/Month (Indian Rs.) for Modular System

Sewing

Operator

6000 40 20 240,000 120,000

Iron man 3000 1 1 3000 3000

Quality

Checker

5000 7 -- * 35,000 --


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*- As per the modular manufacturing philosophy- there should be NO checkers, helpers

And Trimmers, hence all these activities have to be done by the Sewing operator itself.

*- Salary figures are tentative.

Considering 8 Hrs. shift/Day, total available minutes/ shift will be 480.0

Min.

SAM given is 14.0 Minutes, which includes- times for Ironing, Quality

Check and Trimming activities.

Production calculation for Assembly Line -

So, as per the above table, manpower required for Assembly line will be= 50

Expected Out put per shift @ 65% efficiency= (50X480)*0.65/14.0

= 1114 Units/ Shift

Total Labor Productivity (Assembly Line)

= 1114/63 = 17.68 Units/Person/Shift

Production calculation for Modular System –

Expected Out put per shift @ 65% efficiency= (21X480)*0.65/14.0

Helper 2500 11 -- * 27,500 --

Trimmer 3000 2 -- * 6000 --

Supervisor 10000 2 1 20,000 10,000

Total 63 22 331,000 133,000


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= 468 Units/ Shift

Total Labor Productivity (Modular System)

= 468/22 = 21.27 Units/Person/Shift

Expenditure on wages/ Day (assuming Avg. 30 days in one month) for

Assembly Line - 331,000/ 30 = INR. 11033 /Day

Cost / Garment for Assembly Line = 11033 / 1114 = INR. 9.9039 /

Garment

Expenditure on wages/ Day (assuming Avg. 30 days in one month) for

Modular System – 133,000 / 30 = INR. 4433 /Day

Cost / Garment for Modular System = 4433 / 468 = INR. 9.4729

/Garment

Gain / Garment by using Modular system over Assembly Line- INR. 0.4309 / Garment

Prima-facie opting Modular System over Assembly Lines seems a good

deal, but I suggest you to don’t go with this as-

Mark Twain said- “There are three types of lies- lies, damn Lies and

STATISTICS”

The same may happen here also, as we have not covered some crucial

factors, which may directly or indirectly affect this statistical figure.


Manoj TiwariUser 5

These factors are-

1. Machine usage Vs. Idle Machine cost

2. Consistency in quality of the sewn product

3. Consistency in Production/Day

4. Space Utilization

5. Operator’s mentality

Let’s discuss all above points one by one-

1. Machine usage Vs. Idle Machine cost- In a modular system

machine to man ratio is always kept more than 1, so that the multiskilling

can be utilized efficiently.

It means there are always some machines idle at any given point of

time. Generally for a 5-pocket jean modular set-up, we use 25 machines

over 20 Sewing operators; hence 20% of the total machines are always

kept idle.

Keeping the sewing machine Idle is definitely a cost, and it shows

somewhere we are not properly utilizing the available costly resources, if

we calculate straight, by working with 8 Modules for a 5-Pocket jean ,

we are using (unknowingly) 40 extra machines, by which you can

successfully run an assembly line.

The another important point, incase there are small orders of different

styles (For example- One style having asymmetric Back), in this case

clubbing of machines is not possible due to frequent change in machine

settings and we have to go for separate machines for each module.


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Assigning/allocating 2 different separate machines for individual

modules is a costly affair and at the same time machines are not fully

utilized referring to their capacity.

2. Consistency in the Sewn Product quality level- Believing in the

Modular manufacturing concept for garments, the quality of sewn

product has to be ensured by the modular team itself, there is NO quality

check as each operator is responsible for checking and rectification in the

product if required), there is provisions for audits only, once out put is

done.

In this scenario when there is production pressure, operator

misses to check the quality (uncut threads, wrong sewing margins,

unmatched notches, and wrong parts attachment is very common

problems).

As there is only final audit in modular system, till the time you come

to know about poor quality of the product, a big loss of time, material and

money has already been done, which results in cost of poor quality.

Producing and making things wrong are bigger losses than less/no

producing.

3. Consistency in daily production- Lets assume on a fine day 1

modular operator, who is trained for 3 operations in absent.

Unfortunately if he is a crucial operator expert in Inseams or waist band

attach, the production and productivity of that day for that module is in

serious danger.


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In a country like India, where festive seasons, health issues and

climatic calamities are very often, this scenario of key operator’s absent

is very normal.

Here as a replacement you are left with two options, either use a

multiskilled operator from somewhere else or use three different

operators for these operations, both the solutions are going to add extra

cost to the process with no guarantee of achieving required quality level.

At the same time if this operator absence scene happens in

assembly line, you have to deal with one and only one operator, who

does only one operation and finding out a replacement for it, will not be a

big deal for you.

4. Space Utilization- In general practice for a 5- Pocket jean, the space

consumed by 2 modules is equal to 1 Assembly line. Apart from it, we have to provide space for sewing preparatory

for individual module and space for the non productive or idle machines

in the module.

It has been observed that on an average a module takes 2 years to

get matured, till that time you have to compromise with daily avg.

production of 250-300 Pcs ./Day ( against 468 Units/Day as calculated

above @ 65% efficiency) and in the same conditions a line starts

producing out put Avg. 1100 Units/Day(As calculated above) from 8th or

9th day of the line starts.

It means from a space of 2 modules, we will get approximately avg.

500-600 Units/Day out put, which is equivalent to a space of a line,

whereas from a line you can get easily 1100 Units/Day.


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Hence its clear that, to get equivalent out put to an assembly line, we

need infect 4 modules (Equal to the space of 2 lines), it shows

somewhere we are loosing space and not unable to get a logical out put

from the given space.

Space is definitely a big cost, and the above results show better to have

an assembly line over modules. 5. Operator’s mentality- This is one of the most crucial factor which

decides the future performance of any manufacturing system. But

most of the times we skip this point taking as a secondary priority.

This is a well known fact that operator’s training and making

them multiskilled takes a good amount of time, resources in terms of

money and manpower as well as managements patience also.

Now lets think about this concept of multi-skilling from operator’s

mind set, he may think below two points-

A. Why he should learn different operations or different works

when salary is going to be more or less same. Multiskilling will

put extra burden on him without giving no significant monitory

benefits.

B. OK, he will learn more than one or two operations and will

become a multi skilled operator, but as soon as he learns all

this, he will leave this job and join another company who can

pay him better.

In both the cases, the MANAGEMENT who invested so much time and

everything in the operator training and multi-skilling is the LOOSER.


Manoj TiwariUser 9

These scenes don’t occur to such a scale while we are working with

assembly line.

Conclusion- From above discussed points, it’s clear that such a strategic

decision like converting a set-up from Assembly line to modular or vis-versa

may decide the future of the plant and a good deep thought or brain storming

considering all the aspects should be done before decision making.

No doubt, there is nothing left all across the globe for modular systems to

prove further. Their success stories reveal the uniqueness and excellence

right from automobile sector to apparels.

Modular philosophy has its own advantages and benefits, but the

requirement is to run modules with discipline and religiously. There must be

no compromise with fundamentals; otherwise blind follow-up of modules

may come up with bigger disasters.

assembly vs modular manufacturing

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