Priority sequencing in a real world job shop

Abstract

An engineering industry job shop that manufactures 19 types of products against orders is described, with the objective of evaluating a new sequencing rule based on the monetary value of the job and its processing time, the highest value time ratio rule. Analysis of this rule has not appeared in literature on job shop scheduling. For purposes of comparison, based on the performances in past studies, the following four sequencing rules are included: (1) Shortest processing time rule (2) Slack per operation rule (3) First-in, first-out rule (4) Due date rule. These rules were evaluated on the following criteria: work-in- process inventory in monetary terms, and delivery performance, and a combination of the two measures. Results of the study show that the highest value time ratio rule results in minimum work-in-process inventory. The shortest pro cessing time rule results in maximum delivery performance; the same rule is superior on combined measure of performance.