Single-job lot streaming in m-1 two-stage hybrid flowshops

Lot streaming is the process of splitting a production lot into sublots and scheduling those sublots in overlapping fashion in order to reduce the production lead time of the whole lot. In this talk, we present solution methods for the problem of lot streaming one production lot in a two-stage hybrid flowshop with m identical machines at stage 1 and a single machine at stage 2. We try to optimise the number of sublots as well as the sublot sizes. We first decompose the problem into subproblems, each with a fixed number of sublots. A balanced-sublot allocation/sequencing policy is proposed for the subproblem and its optimality is proved. Under this policy the subproblems are then solved efficiently. Finally, we show that more efficient solutions can be obtained if the sublots are required to be equal. As a heuristic solution to the general problem, the performance of the equal-sublot solution is also evaluated.

B.Hammer