Production planning in remanufacturing/manufacturing production system

Remanufacturing end-of-use product is considered as one effective way to provide ecologically sustainable production industry. Realizing promising business opportunities of remanufacturing in addition to its contribution in saving the environment, this is the time for manufacturers to consider performing remanufacturing production activities accompanying their existing manufacturing. Including remanufacturing, production system is significantly different from conventional manufacturing production system. Instead of single forward flow of material in conventional supply chain, system now contains two material flows, named conventional manufacturing flow sourcing from new materials, and recovery flow sourcing from end-of-use products returned back to the production system. Therefore, to use current conventional production planning models in remanufacturing/manufacturing production system (RMPS) is questionable, and the optimal structure of the production system is still need to be further explored. This research focuses on this two flows characteristic and the return process that occurred in RMPS. We recognize that return process of end-of-use products forms sort of cyclical, or looping process in the system, that product release (sales to fulfill demands) and return affect each other, and have significant influence for system performance. For optimal production planning, a cyclic optimization approach is introduced here. The basic idea is to simultaneously consider the whole cyclical process in the system that caused by the return of end-of-use products, and allowing product release and return process to be treated as variables to be determined in generating optimal production plan. Besides remanufacturing and manufacturing production activities, disposing or sending excessive returned end-of-use parts (products) to material recycler are also carefully considered in production planning mechanism, along with all respective inventories. Based on the approach, a linear programming model for generating production plan in capacitated RMPS producing multi products with common parts is constructed, and applied in a numerical example. The result shows a superior optimality performance compared to conventional approach, as a merit that the whole cyclical process are now being included in optimal solution generation model.