INTEGRATING THE LOT-SIZING AND SEQUENCING DECISIONS FOR SCHEDULING A CAPACITATED FLOW LINE

In this paper we consider a general problem of scheduling a single how line consisting of multiple machines and producing a given set of job s. The manufacturing environment is characterized by sequence dependen t set-up times, limited intermediate buffer space, and capacity constr aints. In addition, jobs are assigned with due dates that have to be m et. The objectives of the scheduling are: (1) to meet the due dates wi thout violating the capacity constraints, (2) to minimize the makespan , and (3) to minimize the inventory holding costs. While most of the a pproaches in the literature treat the problem pf scheduling in flow li nes as two independent sub-problems of lot-sizing and sequencing, our approach integrates the lot-sizing and sequencing heuristics. The inte grated approach uses the Silver-Meal heuristic (modified to include lo t-splitting) for lot-sizing and an improvement procedure applied to Pa lmer's heuristic for sequencing, which takes into account the actual s equence dependent set-up times and the limited intermedite buffer capa city. We evaluate the performance of the integrated approach and demon strate its efficacy for scheduling a real world SMT manufacturing envi ronment. Copyright (C) 1996 Elsevier Science Ltd