Question

Four machines used to produce a family of parts are to be arranged into a GT cell. The from-to data for the parts processed by the machines are shown in the table below. (a) Determine the most logical sequence of machines for this data. (b) Construct the network diagram for the data, showing where and how many parts enter and exit the system. (c) Compute the percentages of in-sequence moves, bypassing moves, and backtracking moves in the solution.

1 2 3 4

1 0 10 0 40

2 0 0 0 0

3 50 0 0 20

4 0 50 0 0

Answer 1

(a)

Use Hollier's algorithm to find the most logical sequence as follows:

From \ To	1	2	3	4	From 'sums'	From/To ratio
1	0	10	0	40	50	50 / 50 = 1.00
2	0	0	0	0	0	0 / 60 = 0.00
3	50	0	0	20	70	70 / 0 = Inf
4	0	50	0	0	50	50 / 60 = 0.83
To 'sums'	50	60	0	60

Based on the descending From / To ratio, the most logical sequence is as follows:

3 --> 1 --> 4 --> 2

(b)

Network diagram:

(c)

Total moves = 50+40+50+20+10 = 170

In-sequence moves = 50+40+50 = 140, so, the % is = 140/170 = 82.35%
Bypassing moves = 20+10 = 30, so, the % is = 30/170 = 17.65%
Backtracking moves = 0 or 0%