Production and inventory control of a multi-item multi-stage manufacturing system : simulation modeling, capacitated shipment planning and Kanban design

Abstract

The project work presented in this thesis has proposed solutions related to the control of production and work-in-process inventory in a multi-item multi-stage manufacturing system. A suitable base-stock inventory control policy is recommended to ensure that the desired service levels are maintained between production stages and for the final customers. Concept of coupling the production lines though coupling-stock under suitable assumptions is then introduced to reduce the stock levels at certain consecutive production stages. A framework for demand seasonality and characteristic analysis is also established to enable the inventory control policy to respond to seasonal variations. Monte Carlo simulation was performed on a model of chain of production stages controlled under base-stock policy for the verification of results and to study the effects of stock-outs on base-stock levels. The results of simulation study showed that overall system performance is satisfactory and desired service levels were achieved. Simulation work was also carried out to validate the line coupling concept and its performance under certain conditions. A novel Kanban based visual management system design, which is aligned with the requirements of inventory control policy, along with the material transfer batch sizes between production stages is proposed to facilitate the implementation of inventory control policy. Furthermore, capacitated shipment planning approach is proposed and implemented in form of a spreadsheet-based interface to aid planning personnel in shipment planning under the constraints provided by the inventory control policy.