OPTIMAL AND HEURISTIC MODELS FOR LOT SPLITTING IN A FLOW-SHOP

This paper investigates optimal lot‐splitting policies in a multiprocess flow shop environment with the objective of minimizing either mean flow time or makespan. Using a quadratic programming approach to the mean flow time problem, we determine the optimal way of splitting a job into smaller sublots under various setup times to run time ratios, number of machines in the flow shop, and number of allowed sublots. Our results come from a deterministic flow shop environment, but also provide insights into the repetitive lots scheme using equal lot splits for job shop scheduling in a stochastic environment. We indicate those conditions in which managers should implement the repetitive lots scheme and where other lot‐splitting schemes should work better. Copyright © 1990, Wiley Blackwell. All rights reserved