Essential I.E formulas in garment industry

Essential I.E formulas in garment industry

looking for essential I.E formulas in garment industry ? In this article, garment merchandising is discussing some essential I.E formulas in garment industry and these formulas are given below with examples.

1) SAM = B.M * (1+PF%+MD%)+BHT%

Example:

Single cycle time of operation = 16, 18,15,14,17

Average single cycle time = 16+18+15+14+17 / 5

= 16 second

Rating of the operator    = 85%

Basic Minutes (B.M) = (Average cycle/60)*rating

=   (16/60)*85%

(B.M) = 0.22 minutes

If machine is SNLS, then

MD% = 12.5 %

Personnel fatigue = 7.5%

Bundle handling time =3%

As per SAM formula,

SAM = B.M * (1+PF%+MD %) +BHT%

= 0.22*(1+7.5%+12.5%) +3%

= 0.22*(1+0.075+0.125) +0.03

=0.22*(1.2) +0.03

= 0.26+.03

=0.29 Minutes     (Answer)

Note: Machine delay allowance is different for different machines. Personnel fatigue allowance is 7.5% for sitting operators and 10 % for standing operators, Bundle handing time is standard for all.

2) Weighted Average SAM = (1st Quantity * 1st quantity SAM)+( 2nd Quantity * 2nd quantity SAM)/(sum of quantities)

Example:

Suppose,

Two different orders are running in a same line. Quantity and Sam of one order is 2590 pieces & 17.6 while the quantity and SAM of the other order is 3000 &18.7. Obviously, the impact of 3000 & 18.7 order will be greater than the first order. Therefore we calculate weighted average SAM to know that which quantity and SAM has a greater impact on line efficiency and targets.

As per formula,

Weighted average SAM = (2590*17.6)+ (3000*18.7)/(2590+3000)

= 18.19 (Answer)

3) Wage factor =( Minimum wage per month / working days*shift time )*average efficiency

Example:

Suppose,

A) Minimum wage for skill level 1 operator = 21000 per month

B) Minimum wage of skill level 2 operator = 20000 per month

C) Minimum wage of skill level 3 operator =19000 per month

Now let us calculate wage factor according to skill of the operator,

As per formula,

Wage factor = (21000/26*480)* 90%                                              (For skill 1)

= (21000/12480)*0.90

= 1.51 (Answer)

4) Piece Rate (Formula)= Wage factor (as per skill) * SAM of operation

Example:

Suppose,

Sam = 0.81 minutes

Wage factor =1.51 (for skill level 1)

Piece rate    = 1.51 * 0.81

= 1.22 will be the piece rate of that operator

5) Target = (Number of operators * Shift time / SAM )* 100

Example:

Suppose,

Total Number of operators =60

Shift time = 480 minutes

SAM of garment = 16.2

Average Efficiency of line = 70%

As per formula,

Target = (60 * 480 / 16.2) * 70%

= 1244 pieces/shift

6) Total Operators = (Target * SAM/Shift time)

Example:

How much number of operators will be required for a line of 2000 pieces if the shift time is 480 minutes and average Sam of line is 15.5?

Total operators = [(2000*15.5)/480]

= 65 operators.

 

7) Efficiency =[(SAM produced)/(Available mints)] *100

 Here,

SAM produced = Output * SAM of that garment

Available Mints = (Direct labor * Shift time) + Down time – over time

Example:

suppose output of the line is 1700 pieces per day, Sam of the garment is 16.5 minutes ,direct labor of the line is 68 operators, shift time is 480 minutes, machines down time of line is 280 minutes and over time of the operators is 976 minutes. What will be the line efficiency?

Put all of the above mentioned values in efficiency formula,

Efficiency = [(1700*16.5)/ (68*480) +280-976]*100

= [28050/ (32640) +280-976]*100

= (28050)/(31944) = 87.80 %  (Answer)

8) Line productivity (labor) = (Total output of the line / total number of operators)

Example:

Suppose,

Total output of line = 1500 pieces a day

Total line operators = 61

As per formula = 1500/ 61 =24 pieces

9) Line productivity (Machines) = (Total output of the line / total number of machines)

Example:

Total output of the line = 1500 pieces a day

Total machines in line = 57

Productivity =   1500/57

= 26.31 pieces

10) SAM variance = {(Estimated SAM – Actual SAM)/Actual SAM } *100

Example:

Sometimes buyer changes his/her mind and wants a change in product styling. Let’s suppose at 1st inquiry stage a denim pant style was two darts at knee, waist belt was elastic and yoke attach was safety plus feedo top. At booking stage customer wants a change in styling and demand is make the wasit belt simple, cancel the two darts at knee and attach the yoke on feedo.Then obviously there will be change of SAM and garment labor cost also.

Suppose,

SAM at first inquiry stage was = 22.5 minutes

SAM after change in inquiry = 18.9 minutes

What will be the SAM variance??

As per formula

SAM variance= [(22.5-18.9)/ (18.9)]*100

=19%

 11) Factory capacity = (shift time / SAM) *Total Operators *working days * Efficiency

Example:

Suppose,

Shift time = 480 minutes

SAM = 42.5 minutes

Total operators = 2500

Working days = 26

Efficiency = 75%

As per formula,

Factory capacity = (480/42.5)*2500*26*0.75

= 11.29*2500*26*0.75

=550588 pieces

12) Piece per machine = Total output /Total machines

 Example:

Suppose,

Floor total output = 8455 pieces

Total machines at floor = 277

As per formula,

Piece per machine  =   8455/277

=30.52 piece/machine

13) Man to machine ratio = Total workers / total machine

Example:

Suppose,

Total workers working at floor = 622

Machines operators at floor = 481

As per formula,

Man to Machine ratio = 622/481

=1.29   (Answer)

14) Machine utilization % = (total machine running time/ total available minutes )*100

Example:

Suppose,

Machine running time = 380

Available minutes (shift time) = 520

As per formula,

Machine utilization % = (380/520)*100

=73%

15) WIP calculation = (Piece loaded in line – Line output)

Example:

Suppose,

Piece loaded in line = 30000

Line output   = 2500

As per formula,

Total WIP in line =30000-2500

= 27500 pieces

16) DHU(Defects per hundred unit ) = (Total number of faults / total pieces checked )*100

Example:

Suppose,

A quality checker checked four different pieces, number of faults in first piece was three, number of faults in second piece was five, number of faults in third piece was two and number of faults in fourth piece was seven.

As per formula,

DHU = [(3+5+2+7)/ (4)]

= (17/4)

= 425

17) Rejection percentage =[ Number of pieces rejected / total number of pieces checked]*100

Example:

Suppose,

A quality checker checked a bundle of thirty five pieces and quality of 6 pieces was poor and rejected by the quality checker.

As per formula,

Rejection %age = (6/35)*100

=17%

18) Cost per minutes = (Total cost incurred in labor /Shift time )*total operators

 Example: Try it yourself

19) Production cost per unit = Total labor of the factory/ total number of machine used

 Example: Try it yourself

 20) Cut to pack % =( Total dispatch/total pieces cut)*100

Example:

suppose,

Total dispatch of the month = 576935 pieces

Total cut quantity of that month = 579545 pieces

As per formula,

Cut to pack %= (576935/5954)*100

= 0.96 %

 

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