A garment manufacturer is interested in using the data collected during value stream mapping to evaluate the current state performance of the capacity of its manual assembly line process and would like to identify the ideal batch size for its operations. The productive capacity of the staff is 420 minutes per day. To manufacture a garment after design approval, clothes are cut into desired shape, followed by sewing of front and back, and then attachments of hand, collars, and buttons. The current operating characteristics of each processing step are found in the accompanying table. Note that each step can only process one part at a time and all steps must process the same sized batches.

a. Calculate the average processing time per unit and the capacity at each step assuming batch sizes of:
i. 20 shirts
ii. 30 shirts
iii. 35 shirts
iv. 40 shirts
b. Identify the bottleneck operation for each batch size.
c. What is the optimum batch size after which there will be no improvement in the line’s processing capacity?

Transcribed Image Text:

Shape Cycle time 2 minutes per shirt Sewing Hand Collar 7 minutes 3 minutes 5 minutes Buttons 6 minutes Setup time 15 minutes 18 minutes 0 minutes 10 minutes 20 minutes per batch