Lot Streaming Multiple Jobs in a Flowshop
International Journal of Production Research, Forthcoming
Posted: 29 Jul 2009 Last revised: 30 Apr 2010
Date Written: July 28, 2009
In this paper we consider the advantages of applying lot streaming in a multiple job flow- shop context. The lot streaming process, of splitting jobs into sublots to allow overlapping between successive operations, has been shown to reduce makespan and thus increase customer satisfaction. Efficient algorithms are available in the literature for solving the problem for a single job. However, for multiple jobs, job sequencing, as well as lots sizing, is involved, and the problem is therefore NP-hard. We consider two special cases for which we provide polynomial time solutions. In one case we eliminate diversity of the jobs, and hence the job sequencing decision, and in the other we restrict the number of machines. We show that for jobs with identical processing times and number of sublots, no advantage is obtained by allowing inconsistency in sublot sizing of consecutive jobs. For the two machine case, we also explain why the sequencing and sublot size decision can be approached independently, and supply a polynomial time algorithm for minimising makespan, taking account of attached set-ups on the first machine and transportation times.
Keywords: Scheduling, Lotstreaming, Flow Shop, Makespan, Dominant Machines
JEL Classification: C44, L23, 021
Suggested Citation: Suggested Citation