An imperfect serial-production system with variable production rate, setup cost reduction, random defective rate, and rework process

This paper focuses on an imperfect serial-production system, where a single-type of products is produced. Unequal-sized batch policy is used among subsequent stages. Many researches assume that setup cost is deterministic in production system and is not subject to control. However, in real situations, setup cost can be reduced by the investment cost. This paper assumes that setup cost can be reduced at an added capital investment cost and the production rates in system may vary within given limits in each batch shipments. The shipment lot size of each delivery is unequal and variable. In the actual production, substandard products are inevitable and defective items are produced during the production process. In our model we assume that the defective rate is random with a uniform distribution. In the rework process, all defective products are repaired, no defective products are scrapped. The aim of this model is to the determine the optimal production lot size, number of shipments and adjusting the production rates to decrease the total system cost under reduced setup cost by considering the discrete investment. A solution procedure is proposed for the model and some numerical examples are provided.Maste