Question

An order for 400 of a product is processed on operation A and operation B. The setup time on A is 100 minutes, and the run time per piece is 18 minutes. The setup time on B is 60 minutes, and the run time is 12 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 to overlap the two operations and to split the lot of 100 into two lots of 40 and 60. 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 100 units (40) and sends the units over to operation B. These 60 units should arrive as operation B is completing the first batch of 60; thus, operation B can continue without interruption until all 100 are completed. Complete the operation setup and describe if there are any   flaws?

Answer 1

Without Overlapping Calculation:

Operation time for work station A (100 minutes + (100 × 18 minutes)	1900 minutes
Move time	30 minutes
Operation time for work station B (60 minutes + (100 × 12 minutes)	1260 minutes
Total manufacturing lead time	3190 minutes

With overlapping calculation:

Operation time for work station A (100 minutes + (60 × 18 minutes)	1180 minutes
Move time	30 minutes
Operation time for work station B (60 minutes + (100 × 12 minutes)	1260 minutes
Total manufacturing lead time	2470 minutes

Time saved = Without overlapping - With overlapping = 3190 - 2470 = 720 minutes

There is a flaw of having the work or the setup being completed with an excess of 720 minutes

So if the setup time is done without overlapping the time would be saved is 720 minutes as total!