Case-dont Bother Me

8/3/2019 Case-dont Bother Me

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Case Analysis Dont bother me, I cant cope

Operations Management - 1

Section B

Group 7

A.K. Ashish Anirudh Singh Harender Kumar Kriti Agarwal Saurav Demta Trushant Nagare Vibhu Kapoor


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Summary and context of the case

The case deals with developing a plan to meet a new order received by a small assembly shop. The order

requires increasing the capacity of both the sub-assemblies: Line A and Line B.

Line A: The capacity of this line has to be increased from 315units/day to 420 units/per day. It employs 7

workers. The regular wage per worker is Rs.18/hour and the overtime wage is Rs.30/hour. The assembly

consists of 16 different tasks with a defined precedence relationship. Overtime doesnt lead to any

rejection rate. Sane, the supervisor of Line A has demanded 2 more workers to meet the 33% increase in

production requirement.

Line B: The new order requires the production capacity of this line to increase to 210 units/day. It

employs 2 workers. Overtime on this line leads to a rejection rate of 1% due to fatigue. The cost of unit

rejected is Rs.420. Uma, the supervisor of Line B has also 2 more workers to meet the increased

demand.

The shop operates 8 hours a day. However, this includes 4 rest periods of 15 minutes each. An overtime

of 2 hours is possible on both the lines.

The issue in meeting the increased demand is that both the supervisors have asked for 2 additional

workers whereas Shantha, the owner has specified that it would not be possible to hire more than 3

workers on a short notice. Also the cost of training workers is quite high i.e. Rs.6,000.

It is also not very clear as to why 100% increase in workers is needed to produce 50% more on Line B,

whereas only 30% increase in workforce is being demanded for an increase of 33% workload on Line A.

The analysis below deals with process flow diagram and assembly balancing to find out if the supervisors

are justified in making their demands for additional workers.


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Assembly Layout/Flow Diagram

LINE A

LINE B

1

2

3

4

6

5

8

7

9 10

11

12

13

14

15

16

b

a

c

d

e

f

g

h


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Problems raised and changes/modifications required to resolve the

problems.Shanta can recruit only 3 workers but each assembly line demanded two additional workers i.e. 4 in

total. But due to limited budget constraints we can recruit only 3 workers and assume additional

overtime. We need to decide which sub assembly actually requires two additional workers. Here, weare analyzing the possibility of additional workers in both the sub assemblies and the one in which the

labor cost is minimum is the most feasible.

Analysis

Line A Existing Production 315 Units/Day

Activity Activity Time (Sec) Immediate Predecessor

1 30 None

2 50 None

3 40 1

4 50 15 20 2

6 10 3

7 10 4,5

8 20 2

9 10 6

10 40 9

11 20 7

12 30 7

13 50 9

14 50 10

15 10 1116 40 8,12

Total Lead Time 480

Cycle Time for 315 Units / Day = 420 Mins / 315 Units = 1.33 Minutes/ Unit = 80 Seconds / Unit

No of Work Station required = Lead Time x Prod Units / Available Time = 6 Work Stations

Presently, Mr. Sane is using 7 workstations against the needed 6 work Stations as following.

W/S Activities Time (Seconds) Time (Minutes) Idle Time

(Minutes)

1 1,3 70 1.16667 0.163333

2 2,5 70 1.16667 0.163333

3 4,8 70 1.16667 0.163333

4 6,9,13 70 1.16667 0.163333

5 7,10,11 70 1.16667 0.163333


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6 14,15 60 1 0.33

7 12,16 70 1.16667 0.163333

Available Time (Minutes) = 7 W/S x Cycle Time 1.33 Mins = 9.31

Idle time = 1.31

Efficiency % = 8 Mins / 9.31 Mins = 85.93

Line A Desired Production 420 Units/Day

Cycle Time for 420 Units / Day = 420 Mins / 420 Units = 1 Minutes/ Unit = 60 Seconds / Unit

No. of Work Station required = Lead Time x Prod Units / Available Time = 8 Work Stations

w/s Activities Time (Seconds) Maximum Production

Capacity (# of Units /

day)

1 2 50 504

2 1,5 50 504

3 3,8 60 420

4 4,6 60 420

5 7,9,13 70 360

6 10,11 60 420

7 14,15 60 420

8 12,16 70 360

With the given nature of certain tasks, we cannot group them in a way that each Work Station can have

less or equal to 60 Seconds (Cycle Time) of tasks. Thus, Work Stations 4 and 8 would have Bottleneck

capacity of 360 Units / Day, which is less then desired 420 Units/ Day.

With Work Stations = 9, following organization would be suitable.

w/s Activities Time (Seconds) Maximum Production

Capacity (# of Units /

day)

1 1 30 504

2 2 50 504

3 3,5 60 420

4 4,6 60 360

5 10 40 420

6 7,11,12 60 420

7 9,13 60 420

8 14,15 60 360

9 8,16 60


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Available Time (Minutes) = 9 W/S x 420 Mins each day = 3780

Utilized time = Lead time 8 Mins x Units Produced 420 Units = 3360

Efficiency % = Utilized Time / Available Time 88.89

Line BExisting Production 140 Units/ Day

Activity Activity Time (Sec) Immediate Predecessor

A 40 NoneB 50 None

C 70 A

D 20 A

E 50 A

F 40 B, C

G 60 E

H 30 D, F, G

Lead time 360 6 minutes

W/S Activities Time (Seconds) Maximum ProductionCapacity (# of Units /

day)

1 A, b, c, d 180 140

2 E, f, g, h 180 140



Efficiency % = Utilized Time / Available Time = 100.00

Line BDesired Production 210 Units/ Day

w/s Activities Time (Seconds) Maximum

Production

Capacity (# of

Units / day)

Production

Capacity with 1

Hour Overtime

1 A, b, d 110 229 262 (Not used)

2 C, e 120 210 240 (Not used)

3 F, g, h 130 194 222 (Used for

extra 16 Units

only 36

Minutes)



Efficiency % = Utilized Time / Available Time 100.00


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Solution

On analysis of the given case, as described in subsequent sections following is the

recommendations. Line A: Solution 1 is suitable, if this order has to be continued for more than 91

working days.

# UnitsProduced

/ Day

Per UnitContributi

on (Rs)

Per DayContributio

n (Rs)

Regularwages

(Rs)

# ofworke

rs

Regular hours

OverTime

Hour

s

Wages /Day +

Overtim

e

Contribution / Day /

Worker

420

(Desired)

30 12600 18 9 8 0 1296 1256

420

(Desired)

30 12600 18 7 8 2 1428 1596

315 (Old) 30 9450 18 7 8 0 1008 1206

Solution 1: This recommendation requires hiring two additional resources, which involves Rs. 12000

training cost and per day wages is Rs. 1296.

Solution 2: This solution has continuing with 7 workers with 2 hours of overtime each day. The

differential wage per day including overtime is Rs. 132 in this case. (12000 / 132 = 90.90)Line B: Solution

1 is suitable

# Units

Produced

/ Day

Per Unit

Contributi

on (Rs)

Per Day

Contributio

n (Rs)

Regular

wages

(Rs)

# of

worke

rs

Regula

r hours

Over

Time

Hour

s

Wages /

Day +

OverTim

e

Contributio

n / Day /

Worker

210

(Desired)

30 6300 18 3 8 1 529.2 1923.6

210

(Desired)

30 6300 18 4 8 0 576 1431

140 (Old) 30 4200 18 2 8 0 288 1956

Solution 1: This recommendation requires hiring one additional resource, which involves Rs. 6000

training cost. In this case, the Efficiency of operation is maintained at 100%, but involved overtime for 1

worker for 1 hour. (Actually making 16 extra unit consuming 36 minutes on 3rd workbench), considering

wages of Overtime and 1% rejection due to fatigue.

Solution 2: This recommendation requires hiring two additional resources, which involves Rs. 12000

training cost. But wages exceeds to Rs. 576, more than solution 1.

Case-dont Bother Me

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