Optimization of material requirement planning by fuzzy multi-objective linear programming

Abstract

Material requirement planning (MRP) has evolved from a simplistic representation in the 1980s to today's manufacturing resource planning (MRPII) and enterprise resource planning (ERP) systems in order to meet changing business demands. The persisting momentous drive for lowest costs and highest quality dictates that MRP is deployed in an optimal manner. Multi-objective linear programming (MOLP), which is used simultaneously to optimize decisions through trade-offs between two or more conflicting objectives, has not been reported in MRP-related literature. As an extension of work reported by Yenisey [1], where optimization of material flow in MRP had been presented, a fuzzy multi-objective linear programming (f-MOLP) model is used where two objectives, namely minimization of total cost and minimization of total time of MRP, are targeted. The objective is to find the optimum production rate for each end-product at each period in accordance with the objectives and related constraints. The proposed f-MOLP is solved for two sets of conditions consisting of symmetric and asymmetric cases. The corresponding results show that the proposed models can help manufacturers make better decisions when facing uncertainty about objective functions as well as the constraints set. Degrees of satisfaction demonstrate the applicability of the proposed approach in the context of MRP.