Desired Cycle Time
A company is setting up an assembly line to produce 192 units per eight-hour shift. The following table identifies the work elements, items, and immediate predecessors. Work element
Time (seconds)
Immediate predecessor(s)
A
40
None
B
80
A
C
30
D, E, F
D
25
B
E
20
B
F
15
B
G
120
A
H
145
G
I
130
H
J
115
C, I
Total
720
Solution : First we draw the precedence diagram :
Calculation of Desired Cycle time
Cd = Production Time Available Desired Units of Output
Cd = 8 hours x 60 minutes / hour 192 units = 2.5 minutes
Calculation of Theoretical Minimum Number of Work Stations :
N = ∑t Cd = (40 + 80 + 30 + 25 + 20 + 15 + 120 + 145 + 130 + 115) / 60 2.5 = 720/60 = 4.8 2.5
Since we cannot have any portion of a workstation, we round up upto 5 workstations.
Time (seconds)
Immediate predecessor(s)
A
40
None
B
80
A
C
30
D, E, F
D
25
B
E
20
B
F
15
B
G
120
A
H
145
G
I
130
H
J
115
C, I
Total
720
Solution : First we draw the precedence diagram :
Calculation of Desired Cycle time
Cd = Production Time Available Desired Units of Output
Cd = 8 hours x 60 minutes / hour 192 units = 2.5 minutes
Calculation of Theoretical Minimum Number of Work Stations :
N = ∑t Cd = (40 + 80 + 30 + 25 + 20 + 15 + 120 + 145 + 130 + 115) / 60 2.5 = 720/60 = 4.8 2.5
Since we cannot have any portion of a workstation, we round up upto 5 workstations.