Optimal production scheduling for hybrid manufacturing–remanufacturing systems with setups

Hybrid systems that use both raw materials (manufacturing mode) and returned products (remanufacturing mode) in their production process are considered. The system consists of one facility and necessitates setup for switching from one production mode to another. Since the flow rate of returned products is limited (fixed percentage of the demand rate is considered), switching from one mode to another is unavoidable, and so production and setup scheduling becomes critical for meeting customer demand and manufacturing cost optimization. Analytical solutions for production and setup strategies are obtained, feasibility conditions are derived, and the sensitivity of obtained results over system parameters is investigated. It is demonstrated that there exist two types of systems: mainly manufacturing systems with a relatively low rate of return, and mainly remanufacturing systems with a relatively low use of raw materials. Quantitative criteria distinguishing these two types of systems are developed, and it is shown that systems of different types obey different feasibility conditions and exhibit different optimal behavior.