A relax-and-fix heuristic approach for the capacitated dynamic lot sizing problem in integrated manufacturing/remanufacturing systems

In this paper, the capacitated dynamic lot sizing problem in integrated manufac-turing/remanufacturing systems is addressed. These kinds of production systems are designed to satisfy the demands of different classes of single-level products not only by manufacturing raw materials, but also by remanufacturing returned products. A single machine with a limited capacity in each time period is used to perform both the manufacturing and remanufacturing operations. A mathematical programming formulation is proposed to optimally solve this problem. Since the problem is NP-hard (it is a generalized version of the classical capacitated dynamic lot sizing problem), a relax-and-fix heuristic is developed to solve the problem in a reasonable amount of time. To evaluate the efficiency of the proposed algorithm, some experimental instances are generated and solved. The obtained results show the effectiveness of the proposed algorithm.