Machine buffer sizing based on the theory of constraint principles and the tabu search technique

Abstract

In the last few years, firms’ efforts have been directed towards improvement in the manufacturing cycle, lead times reduction and quality assurance, due to the ever-increasing time-to-market and quality requirements. In this context to achieve better results in terms of shop floor scheduling and lead time reduction, many scheduling approaches have been developed, but most of these fall short of achieving good results because they do not identify clearly where and how much inventory should be employed (e.g. Davis proposed a heuristic for determining work in process inventories in a flow line). This paper deals with problems of work-in-progress (WIP) inventory management, describing an approach based on the combinatorial problem related to WIP size and location on the shop floor, which is a function of buffer sizes in each operation of the production process. The proposed model has been tested in an aeronautical firm where a relevant growth in the output rate level has been achieved using four WIP buffers with a total inventory of 50 batches.