Donât Bother Me, I Canât Cope
Case Study: Donât Bother Me, I Canât Cope
1 | P a g e
Initial Situation
Line â A
Worker = 7 hours
Working time = 8 hours / day
Rest time = 4 x 15 minutes = 1 hour / day
Operating time = (8-1) = 7 hours = 7 x 60 x 60 = 25200 secs
Existing flow rate = 315 / day
Existing cycle time = 25200 /315 = 80 seconds / unit
Target Production = Target flow rate = 420 units / day
Target cycle time = 25200 / 420 = 60 seconds
Total task time = nïi=1 t=I
Number of station required = 480 / 60 = 8
Present number of station available = 7
Additional station required = (8 â 7) = 1
Given that it is difficult to segregate activities in 60 secondsâ duration initially, hence starting station should be manned with 2 workers and revised workflow has been shown in page number 3.

Case Study: Donât Bother Me, I Canât Cope
2 | P a g e
Line â A Precedence Diagram
Initial Workstation Arrangement
CT= 80 80 80 80 80 80 80
70 70 70 70 70 70 70
IT=10 10 10 10 10 10 10
CT = Cycle Time
IT = Idle Time
Efficiency of Line A = (480 x 10 / 7 x 80) % = 85.71%
Case Study: Donât Bother Me, I Canât Cope
3 | P a g e
Revised Workstation Arrangement
Assembly Line â A (Revised)
2W 1W 1W 1W 1W 2W
120 60 60 60 60 120
CT = 60 60 60 60 60 60
X 2 parallel x 2 parallel
station station
Flow rate = 1 / CT = 1 / 60
(Production capacity per day) = (Production time / cycle time)
= 7 x 60 x 60 / 60
= 420 units / day
ï» Required production