Kandace King
6/19/13
Operations Management
Dr. Rhames
3. An assembly line is to operate eight hours per day with a desired output of 240 units per day. The following table contains information on this product’s task times and precedence relationships:
Task Task Times Immediate Predecessors
A 60 —
B 80 A
C 20 A
D 50 A
E 90 B, C
F 30 C, D
G 30 E, F
H 60 G
a. Draw the precedence diagram.
b. What is the workstation cycle time?
c. Balance this line using the longest task time.
d. What is the efficiency of your line balance?
Answers:
a.
b. C = production time per day/required output per day = (8 hour/day)(3600 seconds/hour)/240 units per day = 120 seconds per unit
c.
Work station Task Task time Idle time
I A
D
60
50
10
II B
C
80
20
20
III E
F
90
30
0
IV G
H
30
60
30
d. Efficiency = = = .875 or 87.5%
4. The desired daily output for an assembly line is 360 units. This assembly line will operate 450 minutes per day. The following table contains information on this product’s task times and precedence relationships.
Task Task Time (seconds) Immediate Predecessor
A 30 -
B 35 A
C 30 A
D 35 B
E 15 C
F 65 C
G 40 E,F
H 25 D,G
a. Draw the precedence diagram.
b. What is the workstation cycle time?
c. Balance this line using the largest number of following tasks. Use the longest task time as a secondary criterion.
d. What is the efficiency of your line balance?
Answers:
9. The following tasks are to be performed on an assembly line:
TASK SECONDS TASKS THAT MUST PRECEDE
A 20 —
B 7 A
C 20 B
D 22 B
E 15 C
F 10 D
G 16 E, F
H 8 G
a. Find the cycle time.
b. What is the theoretical number of workstations?
c. Draw the precedence diagram.
d. Balance the line using sequential restrictions and the longest-operating-time rule.
e. What is the efficiency of...