A heuristic algorithm for master production schedule generation with finite capacity and sequence dependent setups

Abstract

Correct formulation of the master production schedule is critically important for the optimization of the management ofa production planning and control system. Most of the models described in the literature solve the problem in two separate sequential stages: lot sizing and then sequencing. This often produces an MPS which is not optimized or even not feasible. On the other hand, when the problem is tackled with models based on mixed integer linear programming, then dimensional constraints have to be respected which can limit the field of applications of the model itself.A complete heuristic algorithm is presented in this paper which solves the problem oflot-sizingand sequencing in a single logic stage, together with the results of an extensive series oftests carried out to compare, in different types of production systems, the performances of the proposed heuristic and those of another algorithm taken from literature. The model concerns a single production line situation with relevant setup problems; on this production line component availability constraints are not considered (the model refers to mono-level bill of material products, but it can be applied also to the most critical level in multi-levels production systems). IntroductionMany industrial sectors attach great importance to (levels of) service, flexibility and elasticity as the company's basic competitive weapons. Phenomena which tend to create a market demand which is extremely variable in time, both in terms of quantity and type of products, are becoming increasingly frequent.Thus, there is a search for solutions in terms of production planning, programming and control models (PP&C) which are both as complete as possible in terms of ability to model the problem and, also, are capable of rapidly regenerating the production schedules which have been prepared when there are modifications or variations in the marketing input. In the case of process production, the basic problems which the PP&C system has to solve relate to the lot-sizing and sequencing stages, since the stage of requirement planning is simplified by the limited number oflevels involved in the bill of materials. Therefore, the primary objective of PP&C systems is the formulation of a master production schedule (MPS) in terms of: