Question

Operations Scheduling. You are a manager of an injection molding shop, and need to schedule several jobs on your largest molding machine. You decide to restrict the order of your choices somewhat to take an advantage of subsequent processing that some jobs must undergo. There are six jobs to be scheduled on the molding machine. Job 1 should be done before job 4 and job 3 before job 5. Processing times, due dates (both in days) and the cost (as a function of time) of being late for each job are as follows: Job Processing time Due date Cost 2 2 4 6 TT 3 3 4 3T 4 2 2 21 5 1 4 6 3 10 2T T a) Find the sequence that will minimize maximum cost. Show all your calculations. (15 pts) b) What is the cost of the sequence found in (a)? (5 pts)

Answer 1

Anwer a= The cost can be minimized with the help of the earliest due date method. So in this method, the jobs will be arranged as per their due dates.

4-5-3-1-2-6 but as per the requirement of the question which states job 1 has to be completed before job 1 and job 3 before job 5 so the new sequence will be

1-4-3-5-2-6

Job	Processing time	Completion time	Due date	lateness
1	2	2	6	0
4	2	2+2=4	2	2
3	3	4+3=7	4	3
5	1	7+1=8	4	4
2	4	8+4=12	8	4
6	3	12+3=15	10	5

Answer b= Total cost =(0*1+2*2+3*3+4*1+4*1+5*2)T =31T