A mathematical modeling approach for material requirements planning in remanufacturing

Remanufacturing as an option for product recovery basically includes disassembly of used products (cores) into parts, inspection of parts, improvement or replacement of used parts if necessary, and finally reassembly of all those parts into new products. Quantity and quality uncertainties of returned products, randomness in core procurement lead time and in disassembly time of cores make the material requirements planning (MRP) task more complex in remanufacturing process. In addition to this complexity, other constraints placed by the nature of remanufacturing systems and cost minimization objective require more sophisticated solution methods than the traditional MRP.In this study, a new mathematical model for MRP in a multi-product, multi-period remanufacturing environment with part commonality is developed. Also, an experimental study to determine significant factors on total cost and computation times is conducted. Analysis of variance of experimental results shows that ratio of purchase cost of a new part to disassembly cost, procurement lead times for cores and new parts and disassembly yield rate are the most influential factors on the total cost. In terms of computational complexity, disassembly yield rate and procurement lead time for core significantly affect the computation time.