Industrial Engineering Tools and Techniques (Basic Concepts)

Industrial engineering is the branch of engineering that involves figuring out how to make or do things better. Industrial engineers are concerned with reducing production costs, increasing efficiency, improving the quality of products and services, ensuring worker health and safety, protecting the environment and complying with government regulations. 
They "work to eliminate waste of time, money, materials, energy and other commodities," according to the Institute of Industrial Engineers. For example, industrial engineers may work to streamline an operating room, shorten a roller-coaster line, make assembly lines safer and more efficient, and speed up the delivery of goods.

Industrial Engineering (IE) = production↑ cost↓ proper use of all elements↑ Efficiency↑ Profit↑

Basically Industrial Engineering department works in major areas as below-

1.     Cycle Time

2.     Takt time

3.     Basic Time

4.     Standard minute value (SMV)

5.     Efficiency

6.     Capacity

7.     Target

8.     Line Balancing

      

      Cycle Time

Cycle time describes how long it takes to complete a specific task/operation from start to finish. Cycle time can be measured with a stop watch.

Cycle Time = (Ending reading of stop watch - Starting reading of Stop Watch)

Takt Time

Takt time is the allowable times to produce one product at the rate of customers’ demand. This is NOT the same as cycle time, which is the normal time to complete an operation on a product (cycle time should be less than or equal to TAKT time).

Takt time is the calculated pace of production based on the average speed at which the customer is buying a product or service. The formula is net available time to produce per time period divided by customer demand per time period. For example when,

Net available time = 4500 minutes / shift (10 operators total man-minutes)
             Customer demand = 500 pieces / shift
             Takt time = (4500÷500) = 9 minutes / piece

Takt time is a very important tool for Lean Line or One Piece Flow Production.
For example, demand from production line is 60 pieces per hour. In one hour you had only 3600 seconds. So takt time for the line will be 3600 seconds/pieces (3600 seconds/60 pieces). So, you know that your target of production. According to this target and garment work content (suppose men’s full sleeve shirt) you have to determine how many operator should be taken to set the line. Let’s assume SAM of the shirt is 20 minutes or 1200 seconds. In one minutes each operator has only 60 seconds. So to produce a pieces in 60 seconds, total number of operator required 1200/60 = 20 nos. (Consider that each operator works at 100% efficiency.)

Basic Time

Basically basic time is almost same as cycle time. Difference is that cycle time is calculated as sec. and Basic time is calculated in Minute with performance Rating.

Formula:

Basic time = (Cycle time/60) x performance rating

                  = (36/60) x 80%

                  = 0.48

Standard Minute Value (SMV)

Let,

Cycle time = 36 sec.

Performance rating = 80%

Bundle allowance, machine allowance & personal allowance = 20%

SMV = Basic time+ Allowance%

         = {(Cycle time (Sec)/60) × Performance Rating} + Allowance %

         = {(36/60) × 80%} + 20%

          = (0.6 × 80%) + 20%

          = 0.48 + 20%

          = 0.576

Example of estimated SMV for basic T-Shirt:

Sl no.	Operation	Average Cycle  time(sec)	Estimated SMV
1	SMV for Number matching front to back part	15	0.24
2	SMV for Shoulder joining	17	0.27
3	SMV for Neck make	16	0.26
4	SMV for Neck joint	19	0.3
5	SMV for Neck piping	18	0.29
6	SMV for Round neck edge tack	20	0.32
7	SMV for Back tap top stitch	38	0.6
8	SMV for Main label attaching	19	0.3
9	SMV for Sleeve hem	19	0.3
10	SMV for Sleeve match	18	0.29
11	SMV for Sleeve joining	38	0.6
12	SMV for Side joining	51	0.8
13	SMV for Care label joining	13	0.29
14	SMV for Body turning	20	0.32
15	SMV for Side top stitch	38	0.6
16	SMV for Neck top stitch	22	0.35
17	SMV for Bottom hem	22	0.35
Total SMV			6.48

Efficiency

Efficiency is define as how much once capable to produce comparing target.

Efficiency = Output/Input

                      = (SMV*Product Quantity) / (Worker*Working Hour*60)

                      = [(38.50*700) / (60*10*60)]*100

                      = 74% (Line Efficiency)

Here,
SMV=38.50
Working hour=10
No. of worker=60

Factory capacity

Factory capacity = (Total Working Minute x No of Workers) / SMV x Efficiency

                                 = [(Work hour x total workers x working day x 60)/SMV] x Efficiency

                                = [(10 x 1500 x 26 x 60)/14.13] x 55%

                                = 828025 pcs/month

Here,

Working Hour = 10

No of Worker = 1500

Working Day = 26

SMV = 14.13

  Efficiency = 55%

Production Target

Target = x Efficiency

             =  x 80%

             = 1630 Pcs/10 Hour

Line Balancing

The word balancing means Equality. It means one should produce equal quantity of next worker as well as to balance all operations of production stages.

Here below the Machine and operation sequence of T-shirt manufacturing process

Machine and operation sequence of T-shirt manufacturing process:

Number matching front to back part

↓

Shoulder joining (by over lock machine)

↓

Neck joint (by plain machine)

↓

Neck over locking (by over lock machine)

↓

Neck piping round the neck (by flat lock machine)

↓

Round neck edge tack (by plain machine)

↓

Back tap top stitch (by plain machine)

↓

Main label attaching (by plain machine)

↓

Sleeve hem (by flat lock machine)

↓

Sleeve Joint (by over lock machine)

↓

Side Seam (by over lock machine)

↓

Care label joining (by plain machine)

↓

Side top stitch (by flat lock machine)

↓

Neck top stitch (by flat machine)

↓

Bottom hem (by flat lock machine)

↓

Inspection

Process layout and line balancing of T-shirt

There are various types of operations, machines and stitches used for making a T-shirt which are enlisted to the given table consecutively with proper man power. This information will provide a complete idea to calculate the SMV for making a T-shirt.

Name of operation	Machines	Stitch type	Man power
			Helper	Operator
Number matching front to back part	Helper		1
Shoulder joining	Over lock	Over edge stitch		1
Neck make	single needle lock stitch	Lock Stitch		1
Neck joint	Over lock	Over edge stitch		1
Neck piping round the neck	Flat Lock	Chain / Flat bed Stitch		1
Round neck edge tack	single needle lock stitch	Lock Stitch		1
Back tap top stitch	single needle lock stitch	Lock Stitch		2
Main label attaching	single needle lock stitch	Lock Stitch		1
Sleeve hem	Flat Lock	Chain / Flat bed Stitch		1
Sleeve match	Helper		1
Sleeve Joining	Over lock	Over edge stitch		2
Side Joining	Over lock	Over edge stitch		3
Care label joining	single needle lock stitch	Lock Stitch		1
Body turning	Helper		1	1
Side top stitch	Flat Lock	Chain / Flat bed Stitch		1
Neck top stitch	Flat Lock	Chain / Flat bed Stitch		1
Bottom hem	Flat Lock	Chain / Flat bed Stitch		1
Total			3	19