A Scheduling Model of Flexible Manufacturing System to Reduce Waste and Earliness/Tardiness Penalties

Nowadays, flexible manufacturing system (FMS) is introduced as a response to the competitive environment. Scheduling of FMS is more complex and more difficult than the other scheduling production systems. One of the main factors in scheduling of FMS is variable time of taking orders from customers, which leads to a sudden change in the manufacturing process. Also, some problems are created in production system such as waste, earliness and tardiness costs, and increase inventory. In this paper, a part of flexible manufacturing system where products are produced in two stages and in multiple repositories, is known as a bottleneck. In this study, a mathematical model for scheduling of this problem considering the limitations of the production system such as flow rate and output reservoirs, variable time order entry, waste resulting from the cessation of production, and the storage capacity of reservoirs is developed. Then, the proposed model has been solved by GAMS software. Results confirm the validity of the proposed model.