Abstract: This paper presents a model to optimize the interrupted multi-stage production system in which the production lot size is constant but the sublot can be equal and/or unequal.And the number of sublots at each stage can be different.We firstly model such a system by minimizing total variable costs,and the corresponding heuristic procedure is also developed.The computational process using the heuristic is illustrated by an example.Furthermore,the effects of restarting and idling costs and the sublot-attached setup cost on the problem are discussed.

Key words: multi-stage production system, lot size, sublot, lot streaming