Scheduling in a flow line manufacturing cells system considering intercellular parts: The tabu search approach

The complexity of a large manufacturing system can be greatly reduced through the applications of cellular manufacturing systems (CMS). However, the implementation of a CMS will inevitably incur the occurrence of the intercellular parts (ICP). These ICP require operations in more than one cell and will let these initially independent cells have some new linkages. These ICP will complicate material flow and shop floor scheduling so that most gains from the CMS will be finally vanished. According to the survey on CMS users, the existence of ICP in the real world CMS is inevitable and by no means a trivial problem. It is worthy of meticulous treatments and thorough studies on its scheduling, and hence, the cellular manufacturing system can get its due.;This research presents a two-stage algorithm to schedule the flow line CMS considering intercellular parts. The major objective of this research is to obtain the final schedule with minimized makespan. In the first stage, the CDS scheduling rule is utilized for each cell to obtain the initial sequences for parts within each cell, and the initial sequence among cells is also assigned in a systematic way. This initial schedule is then improved by the proposed tabu search heuristic (TSH) in the second stage: In stage two, the "local" tabu search improves the sequences of parts within each cell and in each part family, then the "global" tabu search improves the sequence among cells. By combining the search improvements inside the cell and outside the cells, an ultimate schedule occurs within a few search iterations.;Computer programs were developed for the proposed TSH procedure and other critical group scheduling procedures. Performances comparisons were conducted between these procedures and the outcomes demonstrate the proposed TSH performs better than other CMS procedures. Several findings on the final scheduling using the proposed procedure are discussed.