Francis Johnson's plant needs to design an effi cient assembly line to make a new product. The assembly line needs to produce 15 units per hour and there is room for only four workstations. The tasks and the order in which they must be performed are shown in the following table. Tasks cannot be split, and it would be too expensive to duplicate any task.
| |
Task Time
|
Immediate
|
|
Task
|
(Minutes)
|
Predecessor
|
|
A
|
1
|
-
|
|
B
|
2
|
-
|
|
C
|
3
|
-
|
|
D
|
1
|
A, B, C
|
|
E
|
3
|
C
|
|
F
|
2
|
E
|
|
G
|
3
|
E
|
a. Draw the precedence diagram.
b. What is the workstation cycle time?
c. Balance the line so that only four workstations are required. Use whatever method you feel is appropriate.
d. What is the efficiency of your line balance?