Question

The following process tasks, elemental times and precedence relationships are given. Initially, the company expects a forecasted demand of 50 units/hour. Find an assembly line that will produce the necessary output.

Task	Time (in seconds)	Immediate Predecessor
A	55	-
B	30	A
C	35	A
D	22	B
E	50	B,C
F	15	C
G	5	F
H	10	G

Part 2. Complete this exercise again, but this time the company expects a forecasted demand of 20 units/hour. Find an assembly line that will produce the necessary output.  IGNORE THE 50 UNITS/HOUR MENTIONED ABOVE. WE'RE USING THE SAME TABLE ABOVE BUT NOW WITH 20 UNITS/HOUR

Step 1. Draw the precedence relationship network.

Step 2. Determine the potential output rate per hour (day). (16.22)

Compare the maximum output rate with the forecasted demand. If forecasted demand is greater than the maximum output rate, an assembly line with work stations is a possibility.

Step 3. Determine the Takt Time (180, 65.45)

The takt time is the number of seconds between units of output exiting the system.

Note: Since task A has the longest elemental time (55 seconds), it would be the bottleneck constant if we desired to increase output when demand increases. When the takt time goes below 55 seconds, a constraint is violated and we may need to divide up the work in task A into different parts.

Step 4. Compute the theoretical minimum number of work stations. (2)

_________work stations

Step 5. Assign Tasks to the Work Stations (balance the line)

Use the “longest task time rule”.

Use the following rules.

Start with the first station. Make a list of eligible tasks to be performed, following precedence relationships.

Select from the eligible task list by picking the task that takes the longest time. If only one task is eligible, do not use the rule.

When the takt time has been used up at one station or no tasks can be assigned to the remaining time, start a new station.

Work Station	Eligible Tasks	Task Selected	Time	Idle
1
2
3
4

Answer 1