Analysis of production scheduling problems with batch type process

Abstract

This thesis considers four production scheduling problems concerned with batch type process. For each product lot, the objective is to determine both the number of batches (required to produce the lot) and the batch sizes so as to minimize some scheduling measures (including mean flow time, maximum lateness, and makespan) associated with manufacturing lead time. The first problem is concerned with production of various components at a single manufacturing facility where the manufactured components are subsequently assembled into a finite number of end products. Each product is composed of a common component and a product-dependent component, and the product completion time is determined by the completion time of the later scheduled one between the two components. All the components are manufactured in batch process at the single facility and, during batch process, the manufactured components are individually moved to the next (assembly) station. The solution properties are characterized subject to the mean flow time measure, based upon which two efficient solution algorithms are exploited. The second problem is concerned with a similar environment except that each product completion time is measured from components handled in batch process. In this second problem, all the components are manufactured in batch process at a single facility so that each component processing need be treated as completed at the time that the work on all the components in the associated batch is finished. Under the maximum lateness measure, the solution properties are characterized and a branch-and-bound algorithm is exploited. The third problem is a multi-stage flow shop scheduling problem with lot streaming allowed where each job is available at time zero, and each machine can process at most one job at a time, and makespan is the performance measure. Lot streaming is a process of splitting a job into sublots so that the sublots are processed sequentially but treated as i...