Key to Sample Midterm 2
Closed book, Closed notes
1. (20 pts) Consider the following information about a small molding company that subcontracts to major toy manufacturers. A set of jobs, whose numbers indicate the order they arrived at the shop and ready to be processed are given below.
Job | pi | di | 1 | 8 | 26 | 2 | 12 | 28 | 3 | 6 | 32 | 4 | 10 | 35 | 5 | 3 | 38 | 6 | 11 | 48 | 7 | 9 | 50 | 8 | 11 | 51 | 9 | 13 | 53 | 10 | 7 | 64 |
a) Schedule the jobs by using SPT rule. For this rule calculate total tardiness, maximum tardiness, number of tardy jobs, and average tardiness. b) If the company policy dictated that any customer with late delivery will be compensated with a discount proportionate to the amount of days of delay beyond that job's due date, which rule should you use? c) If each tardy job gets $50 + $10*(# of days tardy) discount for each day of tardiness what will be the total loss due to tardiness of some jobs out of the job shop?
2. (30 pts.) An IE is performing job-shop scheduling using TOC method. He has already calculated the following table for making scheduling on the bottleneck machine #4. Job i | 1 | 2 | 3 | 4 | 5 | 6 | ri4 | 0 | 6 | 14 | 23 | 14 | 30 | di4 | 12 | 27 | 19 | 33 | 45 | 60 | pi4 | 10 | 5 | 6 | 12 | 23 | 15 |
a) During solution process he gets a mental block and cannot order the jobs on this machine. Help him complete the following table.
t | S(set of schedulable jobs) | Job selected | [s.4,c.4][Start time of selected job, completion time of selected job] | | | | | | | | | | | | | | | | | | | | | | | | | b) Based on your completed table what is the job sequence on this machine? What is the makespan?
3. (30 pts.) Consider the data below.
Daily demand matrix:
| 40-Day Demand | Daily Demand | Part A | 1200 parts | 30 parts | Part B | 2400 parts | 60 parts | Part C | 3600 parts | 90