Question

DataSpan, Inc., automated its plant at the start of the current year and installed a flexible manufacturing system. The company is also evaluating its suppliers and moving toward Lean Production. Many adjustment problems have been encountered, including problems relating to performance measurement. After much study, the company has decided to use the performance measures below, and it has gathered data relating to these measures for the first four months of operations.

	Month
	1		2		3		4
Throughput time (days)	?		?		?		?
Delivery cycle time (days)	?		?		?		?
Manufacturing cycle efficiency (MCE)	?		?		?		?
Percentage of on-time deliveries	79	%	75	%	72	%	69	%
Total sales (units)	2790		2671		2534		2438

Management has asked for your help in computing throughput time, delivery cycle time, and MCE. The following average times have been logged over the last four months:

	Average per Month (in days)
	1		2		3		4
Move time per unit	0.9		0.6		0.7		0.7
Process time per unit	3.9		3.7		3.5		3.3
Wait time per order before start of production	24.0		26.3		29.0		31.4
Queue time per unit	4.8		5.4		6.1		6.9
Inspection time per unit	0.5		0.6		0.6		0.5

Required:

1-a. Compute the throughput time for each month.

1-b. Compute the delivery cycle time for each month.

1-c. Compute the manufacturing cycle efficiency (MCE) for each month.

2. Evaluate the company’s performance over the last four months.

3-a. Refer to the move time, process time, and so forth, given for month 4. Assume that in month 5 the move time, process time, and so forth, are the same as in month 4, except that through the use of Lean Production the company is able to completely eliminate the queue time during production. Compute the new throughput time and MCE.

3-b. Refer to the move time, process time, and so forth, given for month 4. Assume in month 6 that the move time, process time, and so forth, are again the same as in month 4, except that the company is able to completely eliminate both the queue time during production and the inspection time. Compute the new throughput time and MCE.

Answer 1

Requirement-(1-a): Throughput time = Inspection time + Process time + Queue time + Move time. So, Month-4 Month-1 Month-2 Month-3 0.9 days 3.9 days 4.8 days 0.5 days 10.1 days 0.7 days 3.5 days 6.1 days 0.6 days 10.9 days 0.6 days 0.7 days 3.3 days 6.9 days 0.5 days 11.4 days Move time 3.7 days 5.4 days 0.6 days 10.3 days Process time Queue time Inspection time Througput Time Requirement-(1-b): Delivery cycle time = Wait time + throughput time. So, Month-1 Month-2 Month-3 Month-4 24.0 days 10.1 days 34.1 days 26.3 days 10.3 days 36.6 days 29.0 days 10.9 days 39.9 days 31.4 days --> (c) 11.4 days --> (b) [As calculated in Requirement-(1-a)] 42.8 days --> (c) + (b) Wait Time Througput Time Delivery Cycle Time

Requirement-(1-c): Manufacturing Cycle Efficiency = Value Added Time (= Process Time) / Throughput Time So, Month-1 Month-3 Month-4 Month-2 3.9 days 3.7 days 3.5 days 3.3 days Process time --> (a) 10.3 days Througput Time Manufacturing Cycle Efficiency 10.1 days 10.9 days 11.4 days --> (b) [As calculated in Requirement-(1-a)] --> [(a) / (b)] x 100, rounded-off to one decimal 38.6% 35.9% 32.1% 28.9% Requirement-2: [Increases month-by-month] The Throughput time measure displays The Declivery-Cycle time - days measure displays Manufacturing Cycle Efficiency - days measure displays Favorable trends Favorable trends [Increases month-by-month] [Decreases month-by-month] Unfavorable trends

Requirement-(3-a): Manufacturing Cycle Efficiency = Value Added Time (= Process Time) / Throughput Time Calculation of revised Throughput Time: Month-5 So, 0.5 days 3.3 days 0.7 days 4.5 days Inspection time Month-5 3.3 days --> (a) + --> (b) + Process time Process time Througput Time Manufacturing Cycle Efficiency 4.5 days Move time Througput Time (Queue Time is eleminated) --> (a) / (b) 73.3% Requirement-(3-b): Manufacturing Cycle Efficiency = Value Added Time (= Process Time) / Throughput Time Calculation of revised Throughput Time: So, Month-6 3.3 days 0.7 days 4.0 days Month-6 Process time 3.3 days 4.0 days --> (a) --> (b) + Move time Process time Througput Time Manufacturing Cycle Efficiency Througput Time (Queue Time & Inspection time are eleminated) 82.5% --> (a) / (b)