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Question

The portable henhouses they have designed can be assembled in 10 basic steps, each with a required time and predecessor as shown in the table. There are 8 productive hours available in a day and the manufacturer wishes to produce 40 units per hour.

Task Time (sec) Predecessor
A 25 --
B 35 A
C 20 A
D 55 B
E 45 C, D
F 15 B
G 35 C
H 40 D, E
J 25 F, G
K 30 H, J

Balance the line according to the longest operation rule and calculate the percent idle time. Using the same arrangement of tasks at work stations, what is the greatest output that can be achieved in an eight-hour day and what is the percent idle time of this design?

What will be an ideal response?

Answer 1

Answer: The takt time is 60 ∗ 60/40 = 90 seconds per unit. The tasks assigned to stations are:
Station 1: A = 25 seconds, 65 seconds remaining at station 1
Station 1: B = 35 seconds, 30 seconds remaining at station 1
Station 1: C = 20 seconds, 10 seconds remaining at station 1
Station 2: D = 55 seconds, 35 seconds remaining at station 2
Station 2: G = 35 seconds, 0 seconds remaining at station 2
Station 3: E = 45 seconds, 45 seconds remaining at station 3
Station 3: H = 40 seconds, 5 seconds remaining at station 3
Station 4: F = 15 seconds, 75 seconds remaining at station 4
Station 4: J = 25 seconds, 50 seconds remaining at station 4
Station 4: K = 30 seconds, 20 seconds remaining at station 4

The percent idle time is 35/360 = 9.72%

The cycle time cannot be reduced since station 2 uses the entire 90 second cycle time. Therefore, the greatest output that can be achieved with this arrangement is 40 units per hour for 320 units per eight-hour day.