6.8. An order for 200 of a product is processed on operation A and operation B. The setup time on A is 30 minutes, and the run time per piece is 5 minutes. The setup time on B is 50 minutes, and the run time is 7 minutes per piece. It takes 30 minutes to move a lot between A and B. Since this is a rush order, it is given top priority (president’s edict) and is run as soon as it arrives at either workstation.

It is decided that the two operations will be overlapped and the lot of 200 will be split into two lots of 150 and 50. When the first lot is finished on operation A, it is moved to operation B, where it is set up and run. Meanwhile, operation A completes the balance of the 200 units (50) and sends the units over to operation B. These 50 units should arrive as operation B is completing the first batch of 150; thus, operation B can continue without interruption until all 200 are completed.

a. Calculate the total manufacturing lead time for operation A and for B without overlapping.

b. Calculate the manufacturing lead time if the operations are overlapped. How much time is saved?