A Mathematical Modeling Approach for Materials Requirements Planning in Remanufacturing

Abstract

(ProQuest: ... denotes formulae omitted.)1.IntroductionTopics such as the benefits of green production, social responsibility, legislative regulations, environmentally conscious manufacturing, reverse logistics and product recovery have recently gained growing attention due to increased environmental concerns of consumers (Inderfurth, 2004; Rubio and Corominas, 2008; Li, Gonzalz and Zhu, 2009; Nenes and Nikolaidis, 2012). The collection and reuse of products and materials have a long history and hence are not new concepts as seen in the long-standing practices of paper recycling, scrap metal collecting and deposit systems for glass bottles. However, all these operations need to be systematically performed and managed in order to benefit from reverse logistics.Product recovery aims to minimize the amount of waste through recovering parts and materials from returned products by means of recovery options such as remanufacturing or recycling (Nakashima, Arimitsu, Nose and Kuriyama, 2002). Reverse logistics represents the first stage of product recovery from the point of view of the supply chain. There are numerous definitions of reverse logistics suggested in the literature (e.g. Fleischmann et al., 1997; Dowlatshahi, 2000; Brito and Dekker, 2002; Rogers and Tibben-Lembke, 2001; Stock, 2001; Kim, Song, Kim and Jeong, 2006). As a notable example among others, Carter and Ellram (1998) describe reverse logistics as a process through which firms can become more environmentally efficient by means of recycling, reusing and reducing the amount of materials used.Figure 1 shows the basic product recovery options in reverse logistics. All of these options require the product to be collected, processed and redistributed into the market (Guide and Jayaraman, 2000). The key difference between them lies in the processes of reprocessing and recovery. Remanufacturing, which is one of the recovery options shown in Figure 1 and constitutes the main subject of this paper, refers to the process of recovering materials from used products (Tang, Grubbstrom and Zanoni, 2004). In other words, it is the process through which used products are restored to meet quality standards set for new products. Accordingly, old or worn-out products are completely disassembled in the process of remanufacturing, and their components are removed, cleaned and inspected if necessary, while some parts can also be replaced and upgraded as needed. Subsequently, the product is reassembled and tested to verify if it meets the performance level of a new product. Therefore, it is possible to upgrade an old or worn-out product in this process of remanufacturing. A remanufactured product can thus be composed of both newly manufactured parts and disassembled components (Ijomah, Mcmahon, Hammond and Newman, 2007).Recoverable manufacturing systems, among which remanufacturing is included, have particular characteristics that create difficulties in management, planning and control of supply chain functions. This, in turn, further complicates materials planning by causing uncertainties in timing, quantity and quality of cores, part matching restrictions, stochastic routings and highly variable processing times (Guide, 1999; Gungor and Gupta, 1999; Guide, 2000; Guide, Jayaraman, Srivastava and Benton, 2000; Ferrer and Whybark, 2001; van Nunen and Zuidwijk, 2004). These characteristics hence prevent traditional production planning methods from being directly used in remanufacturing environments. For instance, information on the supply of different parts disassembled from different cores (or returned products) should be incorporated into materials planning decisions (Guide and Spencer, 1997). Furthermore, the capacity for disassembling cores needs to be checked for a feasible materials plan (Guide, Srivastava and Spencer, 1997). The majority of studies in the literature suggest that a new line named parts from disassembly is added into materials plan table. …