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MGMT 36100: HW 01
40 Points
Due: January 27, 2010
Question 1:
A fourstage process consists of the
following: machines B1 and B2 in
parallel at stage 1, machine M1 at stage
2, then a buffer (F1), then machine D1
at stage 3 followed by machines G1 and
G2 in parallel at stage 4. Processing
times are (in minutes): B1: 9, B2: 9, M1:
6, D1: 5, G1: 8 and G2: 12.
(a)
Draw a neat process flow diagram.
(b)
What is the minimum TPT
?
9 + 6 +5 + 8 = 28 minutes
(c)
What is the hourly capacity for each stage
(round off to 2 decimal places)?
Stage 1: 60 [min /hour] / 9 [min/unit] + 60 [min /hour] / 9 [min/unit] = 13.33 [units/hr]
Stage 2: 60 / 6 = 10 [units/hr]
Stage 3: 60 / 5 = 12 [units/hr]
Stage 4: 60 [min /hour]/ 8 [min/unit] + 60 [min /hour] / 12 [min/unit] = 12.5 [units/hr]
(d)
Identify the bottleneck stage and the process capacity
. Stage 2.
10 [units/hr]
(e) Suppose you can add only one machine in parallel at the bottleneck stage.
A machine with higher capacity
costs more.
You want to buy the least expensive machine.
What should be the design cycle time for
the new machine so that you increase the process capacity as much as possible
?
We should increase the capacity of stage 2 from 10 to 12 [units/hr]. Thus, this
additional machine needs to produce 2 [units/hr] or it should have the design CT =
30 [min /unit].
Parts (f), (g) and (h) are based on the schedule described in part (f).
(f)
Odd numbered jobs are released to B1 starting at time 0 every 12 minutes. Even numbered jobs are
released to B2 starting at time 6 every 12 minutes. At stage 4, odd numbered jobs are scheduled on G1 and
even numbered jobs are scheduled on G2.
Plot jobs J2, J3, J4, J5 and J6
.
0
4
8
12
16
20
24
28
32
36
40
44
48
Notice that for this schedule, we do not need the buffer.
(g)
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 Spring '10
 panwalker
 Management, Hour, Pariah group, $12.5, 2hr

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