LAYOUT STRATEGY
1. An assembly line has been designed to make battery-powered beverage mixers. Task details are shown in the table below:
|
Station
|
Task Assigned
|
Task Time (minutes)
|
|
1
|
1
|
3.0
|
|
2
|
3; 4
|
1.5; 2.0
|
|
3
|
2; 5; 6
|
1.5; 1.5; 1.0
|
|
4
|
7
|
3.0
|
|
5
|
8
|
2.5
|
|
6
|
9; 10; 11
|
2.0; 1.0; 1.0
|
a. What is the assigned cycle time (in minutes)?
b. What is the maximum output rate of this line in mixers per hour?
c. What is the total idle time per cycle?
d. What is the assembly line's efficiency?
2. Departments A, B, C, and D need to be assigned to four rooms 1, 2, 3, and 4. These rooms are arranged in a row, in that order, with 20 meters between each. The departmental work flows are contained in the table below.
|
Flow Matrix
|
|
Dept. A
|
Dept. B
|
Dept. C
|
Dept. D
|
|
Dept. A
|
0
|
30
|
5
|
20
|
|
Dept. B
|
5
|
0
|
40
|
20
|
|
Dept. C
|
0
|
10
|
0
|
40
|
|
Dept. D
|
10
|
5
|
0
|
0
|
a. What is the material handling total of assigning A-1, B-2, C-3, D-4?
b. What is the material handling total of assigning A-1, B-3, C-4, D-2?
3. There are three work centers (A, B, and C) behind the financial aid counter at a nearby university. They can each fit into any of three office spaces (1, 2, and 3) off the corridor behind the desk. There is no student contact in these areas, only workers. The distance 1-2 is 20 feet, 2-3 is 30 feet, and 1-3 is 50 feet. The matrix of work (trips per day) at the three centers is in the following table. Remember that each trip must be a round-trip (from 1 to 2 and back, for example).
|
A
|
B
|
C
|
|
A
|
--
|
20
|
0
|
|
B
|
45
|
--
|
25
|
|
C
|
60
|
0
|
--
|
a. How many possible assignments are there? List them.
b. Calculate the total distance traveled in each of these assignments.
c. Which assignment minimizes distance traveled?
4. A firm is planning to set up an assembly line to assemble 40 units per hour, and 57 minutes per hour are productive. The time to perform each task and the tasks which precede each task are:
|
Task
|
Preceding Task
|
Time to perform (min.)
|
|
A
|
--
|
.69
|
|
B
|
A
|
.55
|
|
C
|
B
|
.92
|
|
D
|
B
|
.59
|
|
E
|
B
|
.70
|
|
F
|
B
|
1.10
|
|
G
|
C, D, E
|
.75
|
|
H
|
G, F
|
.43
|
|
I
|
H
|
.29
|
a. Draw a network diagram of precedence relationships.
b. Compute the cycle time per unit in minutes.
c. Compute the minimum number of workstations required to produce 40 units per hour.
d. Balance this line using longest processing time.
e. What is the efficiency of the line obtained in part d?