Abstract

Today’s manufacturing industries in many countries have developed systematic product recovery, remanufacturing and recycling procedures in an environmentally supportive manner to release the regulatory pressure as well as to achieve economic benefit. This thesis presents a mixed integer programming model addressing production planning problems in hybrid system of manufacturing and remanufacturing. The objective of solving the mathematical model is to minimize the total cost based on the optimal quantity of new items to manufacture and the optimal quantity of returned products to remanufacture in each period of the planning horizon. The proposed model has a distinctive feature that considers the uncertainty of remanufacturing time for the same type of returned products. A new heuristic solution method, similar to Silver-Meal heuristic for solving traditional lot-sizing problems, is developed to solve the considered production planning problems in hybrid manufacturing-remanufacturing systems is developed in this thesis. The developed heuristic is examined using various example problems generated in three dimensions (problem size, returned products quantity and category quantity). The results show that it can generate optimal or close-to-optimal solutions for all tested example problems with much reduced computational time. The model and the solutions were analyzed and sensitive analysis is conducted to investigate the performance of the developed model and solution method.