MENG 452: Manufacturing Planning and Shop Loading

Tutorial # 6Arranging Machines in GT Cell

Dr. Mohamed SALAH

Arranging Machines in a GT Cell (Hollier Method 2)

To:

From: 1 2 3 4

1 0 10 0 402 0 0 0 03 50 0 0 204 0 50 0 0

•Four machines used to produce a

family of parts are to be arranged

into a GT cell. The From-To data

(From/To chart) for the parts

processed by the machines are

shown in the table.

(a) Determine the most logical machine sequence 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.

Hollier Method

Step 1 & 2:To

From 1 2 3 4“From”

sums

1 - 10 0 40 50

2 0 - 0 0 0

3 50 0 - 20 70

4 0 50 0 - 50

“To”

sums50 60 0 60 170

Step 3

Op. From ToFrom/To

ratioSequence

1 50 50 1.0 2

2 0 60 0 4

3 70 0 1

4 50 60 0.83 3

Sequence: 3 1 4 2

Solution: (a) Hollier method 2

Hollier Method

(b) Network diagram:

3 1 4 270 50

20

40

10

50 60

10

(c) % in-sequence moves = (50 + 40 + 50) / 170 = 0.824 = 82.4%

% bypassing moves = (20 + 10) / 170 = 0.176 = 17.6%

% backtracking moves = 0

Performance Measures

1. Percentage of in-sequence moves

2. Percentage of bypassing moves

3. Percentage of backtracking moves

Each measure is computed by adding all of the values

representing that type of move and dividing by the total

number of moves.

It is desirable for the percentage of in-sequence moves to

be high, and for the percentage of backtracking moves to

be low.

Bypassing moves are less desirable than in-sequence moves,

but better than backtracking.

Sheet

To:

From: 1 2 3 4

1 0 5 0 25

2 30 0 0 15

3 10 40 0 0

4 10 0 0 0

Determine a logical machine arrangement using Hollier Method 2

Sheet

Sheet

Part Weekly quantity Machine routing

A 50 3 2 6

B 20 5 1

C 75 5 4

D 10 5 4 1

E 12 3 2 6

F 40 2 6

2. The following table lists the weekly quantities and routings of six parts

that are being considered for cellular manufacturing in a machine shop.

Parts are identified by letters and machines are identified numerically.

For the data given, (a) develop the part-machine incidence matrix, and

(b) apply the rank order clustering technique to the part-machine

incidence matrix to identify logical part families and machine groups.

Sol. P#2Solution: (a) See step 1. (b) See steps 1 through 3.

Step 2

A B C D E I Rank A B C D E I

1 1 1 5 2 1 1 1

2 1 1 1 1 6 1 1 1

3 1 1 3 3 1 1

4 1 1 6 5 1 1 1

5 1 1 1 4 1 1 1

6 1 1 1 2 4 1 1

Rank 3 8 9 6 1 10

A E F D B C

2 1 1 1

6 1 1 1

3 1 1

5 1 1 1

1 1 1

4 1 1

Rank 1 2 3 4 5 6

Part families and machine groups: I = (A, E, F) and (2, 6, 3)

II = (D, B, C) and (5, 1, 4)

Sheet

3. In Problem (2), two logical machine groups are identified by rank order

clustering. For machine group including machine 6:

(a) determine the most logical sequence of machines for this data.

(b) Construct the network diagram for the data.

(c) Compute the percentages of in-sequence moves, bypassing moves,

and backtracking moves in the solution.

Part Weekly quantity Machine routing

A 50 3 2 6

B 20 5 1

C 75 5 4

D 10 5 4 1

E 12 3 2 6

F 40 2 6

Solution: (a) Hollier method applied to first machine group (machines 2, 6, 3):

SheetStep 2

2 6 3 From From sums To

sums

From/To ratio

Order

2 - 102 - 102 2 102 62 1.64 2

6 - - - 0 6 0 102 0 3

3 62 - - 62 3 62 0 1

To 62 102 0 164

Sequence: 3 2 6

(c) % in-sequence moves = (62 + 102)/164 = 1 = 100%

% bypassing moves = 0/164 = 0 = 0%

% backtracking moves = 0/164 = 0 =0%

(b) Network diagram

Note: solve the next cell (1,4,5)

Thanks&

Best Wishes