Systematic Categorization of Reuse and Identification of Issues in Reuse Management in the Closed Loop Manufacturing

For reducing environmental loads induced by the manufacturing industry, reuse of manufactured products is an important measure. To obtain the maximum benefits of reuse, however, we have to understand the mechanisms of reuse and select the correct reuse type according to product characteristics. For this purpose, we propose a systematic categorization of reuse types and identify issues regarding reuse implementation in this study. We also investigate two typical issues that arise: determining the sales period of the reconditioned product and the order and stock management for the reconditioning process, taking copying machines as our example. Recently, there has been growing concern regarding environmental problems. The manufacturing industry should greatly consider reduction of the environmental load created by the entire life cycle of the products that are manufactured and delivered to the users. There are several life cycle options such as "reduce," "reuse," and "recycle," which are means of reducing the environmental load. In particular, reuse is one of the most efficient options. It is effective for reducing material consumption and waste by using the products or parts for multiple life cycles while providing the required functions to the users. Besides, the environmental load resulting from material circulation is usually smaller than that from recycling. This is because used products or parts are disassembled into parts or module levels in reuse, whereas they are disassembled to the material level in recycling. Therefore, promoting reuse is of importance in making manufacturing systems sustainable. However, there are not many cases in which reuse is implemented effectively in real-world situations. In product reuse, for example, returned products have to be passed on to other users who have different requirements from those of the original users. Therefore, the matching of supply and demand in terms of timing, quality, and volume is more difficult than that in selling virgin products. This occasionally causes an imbalance between supply and demand. For this reason, we need to control the circulation of products or parts, rather than placing this responsibility in the users' hands, to achieve effective reuse. When discussing methods of circulation control for product or part reuse, it is essential to understand mechanisms for reducing environmental load through reuse, and the variations in these reuse types. The primary focus of this paper is on categorizing reuse and identifying the issues related to each type of reuse. We adopt several criteria such as objects to be reused, means of product collection, required functionality, and end-of-life treatment. We identify the issues of supply and demand balance and uncertainty in volume and quality of returned products and investigate the influence of these issues on each type of reuse. This analysis will indicate the correct strategy for implementing reuse based on their characteristics. In section 2, we discuss the mechanisms of reuse, as well as the categorization of reuse types in terms of several criteria. We also discuss control issues in managing each type of reuse operation. In section 3, we investigate two issues identified in section 2. We discuss timing and volume fluctuation in selling reused products.