Operations and Supply Chain Management The Core

188 OPERATIONS AND SUPPLY CHAIN MANAGEMENT
d.
FEASIBLE
TASKS
TASK
TASK TIME
(SECONDS)
REMAINING
UNASSIGNED TIME
Station 1
Station 2
Station 3
Station 4
Station 5
A, B
B, D
C, D
D
E
F
G, H
G
I, J
J
A
B
C
D
E
F
H
G
I
J
28
13
35
11
20
6
25
23
37
11
Station 6 K K 27 21
e. Solution same as above.
20
7
13
2
28
22
23
0
11
0
LO6–4 SOLVED PROBLEM 5
An assembly process requires the following five tasks that must be done in sequence:
TASK
TASK TIME (MINUTES)
A 10
B 15
C 5
D 15
E 15
Total work content
60 minutes
What is the trade-off between the capacity and the efficiency of assembly-line configurations that
have between one and four stations?
Solution
Recall that Efficiency = Work content/(Number of workstations × Cycle time).
The first configuration has all the tasks assigned to a single station as follows:
CONFIGURATION 1
TASKS
ASSIGNED
STATION WORK
CONTENT (MINUTES)
CYCLE TIME
(MINUTES)
CAPACITY
(UNITS PER HOUR)
EFFICIENCY
(PERCENT)
Station 1 A, B, C, D, E 60 60 1 100.00
The second configuration splits the tasks between two stations. Note that the tasks must be done
in sequence. Using trial and error, the best assignment is as follows:
CONFIGURATION 2
TASKS
ASSIGNED
STATION WORK
CONTENT (MINUTES)
Station 1 A, B, C 30
Station 2 D, E 30
CYCLE TIME
(MINUTES)
CAPACITY
(UNITS PER HOUR)
EFFICIENCY
(PERCENT)
30 2 100.00
This configuration splits the tasks between the two workstations such that the work content is
the same in each station (a perfectly balanced system). Using the configuration, one unit can be
made every 30 minutes or two units per hour.