Don’t Bother Me, I Can’t Cope

Case Study: Don’t Bother Me, I Can’t Cope

1 | P a g e

Initial Situation

Line – 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 = ni=1 t=I

= (30+50+40+50+20+10 +10 +20+ 10+ 40+ 20+ 30+50 + 50 + 10 + 40) = 480 seconds

Number of station required = 480 / 60 = 8

Present number of station available = 7

Additional station required = (8 – 7) = 1

Given that it is difficult to segregate activities in 60 seconds’ duration initially, hence starting station should be manned with 2 workers and revised workflow has been shown in page number 3.

Case Study: Don’t Bother Me, I Can’t Cope

2 | P a g e

Line – 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: Don’t Bother Me, I Can’t Cope

3 | P a g e

Revised Workstation Arrangement

Assembly Line – 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

 Required production