Question

Problem Statement: A factory producing the new COVID-19 at-home testing kits is determining how to best line balance their production process. There are 12 steps to the production process, and they are presented below, along with their predecessors and how long it takes to complete each task. Assume all times are in minutes. This facility operates for 7 hours per day. Task C D E F G H I J K L A B Nil A B B B B Immediate Predecessor Task Time C D G E 7 5 1 LF HJ K 4 6 7 12 6 6 2 2 12 A. Draw a Precedence Diagram for this Operation B. Their daily demand for these kits is 28 test kits per day. What is the takt time? C. Calculate the number of workstations that you would need D. Based on the Largest Candidate Rule, assign tasks to workstations E. How efficient is this balanced line? F. As an IE, the factory has asked you to come in and help them with their facility layout. Create a work-flow layout in Visio that shows the workstations you have designated and the tasks that are assigned to each workstation. Make sure to include the flow between workstations.

Answer 1

A.

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B.

Takt time = (7 * 60) minutes / 28 kites = 15 minutes per kit

C.

Sum of task times = 70 minutes

Number of workstations needed theoretically = Sum of task times / takt time = 70/15 = 4.7 or 5 stations.

D.

Station	Remaining time	Eligibles	Was fit	Assigned time	Time remains	Idle time
I	15	A	A	12	3
	3	B	-	-	3	3
II	15	B	B	6	9
	9	C, D, E, F	C	6	3
	3	D, E, F	D	2	1
	1	E, F, G	-	-	1	1
III	15	E, F, G	F	12	3
	3	E, G	E	2	1
	1	I, G	I	1	0
	0	G, J	-	-	0	0
IV	15	G, J	G	7	8
	8	H, J	H	5	3
	3	J	-	-	3	3
V	15	J	J	4	11	1
	11	K	K	6	5
	5	L	-	-	5	5
VI	15	L	L	7	8	8

E.

Efficiency = Sum of all task times / (no. of stations * cycle time) = 70 / (6*15) = 77.78%