Supply chain optimization of batch production plants

Abstract

"Supply Chain" is a network of interlinked stages that are associated with converting the raw materials to finished products and further its distribution to end users. This network includes the stages of supply, production, inventory, logistics etc. The goal of the supply chain optimization is to achieve shortest production times, smallest level of inventories that would meet the customer demands, lowest delivery cost and maximum level of customer satisfaction. The supply chain optimization problem considered in this thesis work mainly concentrates on three of the stages of supply chain namely: production, inventory and logistics and is confined to only batch processing plants. These plants operate in a non-continuous manner, receiving inputs at certain times, operating for some duration, and then producing outputs after some time. The batch mode of production involves the movement of material through the different stages of processing in a discrete manner. The aim of this research work is to develop an overall solution procedure that can combine these three stages while simultaneously satisfying the objectives of supply chain optimization mentioned above. To achieve this aim, initially, mathematical models have been proposed for each of these stages. The models proposed for the production stage have variety of objective functions i.e. minimizing makespan or minimizing overall tardiness or minimizing earliness. By changing the objective function and few other constraints in the production model the objective of minimizing overall inventory and changeover costs can be achieved. For logistics stage, the proposed model aims at minimizing overall transportation cost. Finally, an overall solution procedure is built using the models proposed in these stages. Several examples have been studied in this thesis to demonstrate the capabilities of the proposed models