MACHINE SCHEDULING MODELS IN ENVIRONMENTALLY FOCUSED CHEMICAL MANUFACTURING

A case problem involving the strategic repositioning of a chemical fin ishing operation from long cycle, make-to-stock production of high vol ume commodity products, to short cycle, make-to-order production of lo w volume speciality products is described. The focus of the analysis i s on makespan feasible scheduling of parallel mixers over a short orde ring cycle to minimize the resultant waste solvent stream. A model of the physical manufacturing process with respect to the scheduling crit eria is described. This model is used in conjunction with a multi-star t descent scheduling algorithm based on dispatching rules for clusteri ng and sequencing followed by local improvement based on random number s. A series of computational studies using the algorithm in conjunctio n with data from the case problem are described. Implementation issues associated with the case problem are emphasized.