Title: Lot-splitting for inspection in a synchronised two-stage manufacturing process with finite production rates and random out-of-control shifts in the first stage

Authors: Elkafi Hassini, Raymond G. Vickson

Addresses: DeGroote School of Business, McMaster University, 1280 Main St. West, Hamilton, ON, L8S 4M4, Canada. ' Department of Management Sciences, University of Waterloo, 200 University Ave. West, Waterloo, ON, N2L 3G1, Canada

Abstract: We consider a non-repetitive manufacturing environment where the first stage will successively process different types of items that require different set up modes. Optimal sublot sizes are determined by studying the trade-off between the cost and time spent in restoration and rework. In addition, we discuss the resulting economical batch sizes, number of sublots, and processing rates. Finally, we provide recommendations on how to design the material handling flow system to implement our suggested inspection policies. Some of the managerial implications we found is that quality improves significantly when Stage 2 is more responsive (has faster processing times) than Stage 1 and when large batch sizes are divided into more sublots. Depending on the relative magnitude of poor quality and rework costs, we show that there is a threshold for the batch size under which sublot formation becomes inefficient. ]Received 17 July 2007; Revised 30 September 2007; Accepted 12 October 2007]

Keywords: lot splitting; quality inspection; finite production rates; two-stage production; multi-product; applied optimisation; non-repetitive manufacturing; materials handling; material flow; inspection policies; batch size; sublot formation.

DOI: 10.1504/EJIE.2008.017352

European Journal of Industrial Engineering, 2008 Vol.2 No.2, pp.207 - 229

Published online: 01 Mar 2008 *

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