LESSON 11:

Apuntes

LESSON 11: OPERATIONS SCHEDULING There are a lot of techniques for scheduling operations in a job shop. We are going to look at these 3 basic ones: ● First Come First Serve (FCFS): Least efficient method ● Shortest Processing Time (SPT): Quickest one first ● Earliest Due Date (EDD) We’ll use Average COmpletion Time (ACT), Average Job Lateness (AJL) and Average number of Jobs in the System (AJS) (work-in-process). There’s three type of inventory: raw material- work-in-process and finished goods inventory ● Accountants look at work-in-process as an asset, from an operation point of view it’s a liability. Work-in-process starts to go up from an operations point of view, I’m accumulating products and I’m not finishing anything. I want that number to be low ● ACT we want it low ● AJl we also want it low Processing time→ comes from past experience. If i’ve never worked on it, there’s standard timings Due date → working with the customer, Flow time → Processing time + idle time FCFS Jobs Processing time Due date Job Proc time Flow Time Due Date Late A 2 7 A 2 2 7 - B 8 16 B 8 10 16 - C 4 4 C 4 14 4 10 D 10 17 D 10 24 17 7 E 5 15 E 5 29 15 14 F 12 18 F 12 41 18 23 41 120 54 D needed 10 day...