Aggregate planning in hybrid flowshops

摘要

We present a linear programming based heuristic for the solution of class of aggregate level planning problems in hybrid flowshops (flowshops with several machines per stage). First, the general planning problem is modelled as multi-level with parallel processors, multi-item, capacitated, lot-sizing with set up times. We suggest a hierarchical approach which sequentially loads the stages; each stage is constrained by the solution of its preceding stage and each stage is treated as a mutli-item, capacitated, lot-sizing problem with setup times on parallel pro- cessors. We show how this latter problem may be reformulated and solved heur- istically as a sequence of network problems (trans-shipment problems) in which the amount of capacity lost in setups is fixed for each period and each processor. The model is within the computing reach of a PC.