CIRP Annals - Manufacturing Technology

1. Introduction 

Although the concepts of closed-loop manufacturing and life cycle design have been well established in recent years [1,2], there are very few examples of their implementation. The reuse option in particular is not widely adopted even though its effectiveness in the reduction of environmental load is superior to that of the recycling option; this is because the reuse option is not an easy one, since it requires the precisematching of supply and demand in terms of both timing and quality [3]. Leaving product returns to user’s discretion may lead to the untimely supply of reused products or parts for their demand. To overcome this problem, we have proposed forced circulation in which products are compulsorily taken back for reuse in order to exhaust the functionality and life of the products and parts [4]. To implement this strategy, we need to select appropriate scenarios, where the users would not resist the implementation. We have applied this strategy to the use of photoconductor drum units in copiers, which are expendables and are supplied by manufacturers on the basis of maintenance contracts. In this case, however, reuse is limited to expendable parts alone and not the entire equipment. In this paper, we propose intraoffifice circulation of offifice automation equipment as a strategy to achieve effective product reuse. In this paper, Section 2 describes the concept of intraoffifice circulation, and Section 3 discusses the quantifification of user requirements and available product functionality. In Sections 4 and 5, we propose amethod to optimize the reuse plans and demonstrate its application to the use of copiers in the offifices of Waseda University. Finally, Section 6 presents conclusions of this paper. 

2. Concept of intraoffifice circulation 

The objective of product reuse is to reduce the environmental load during production phase of a product by ensuring the exhaustion of the product life through multiple users with different user characteristics. Products should be collected back from a user after a certain period and reallocated to other users with different characteristics; for example, they should be reallocated from heavy users to light users or from users who require high functionality to those who do not. It is therefore important to identify user characteristics and control the timing of product returns to achieve effective product reuse. However, it is rarely possible to meet these conditions in a usual mass market. We therefore focus on offifice automation equipment used in one offifice. In the following discussion, we consider a copier machine as an example of offifice automation equipment. A medium- to large-scale offifice usually has copiers installed in each section of the offifice,which has a specifific nature ofwork, and thus each copier has a different usage characteristic. We assume that the copiermanufacturermakes ablanketcontract toprovidecopiers in all sections of the offifice for a certain period of time. The manufacturer periodically exchanges the copiers among the different sections based on theusagecharacteristics of eachcopier so as toutilize the life and functionality of the copiers as much as possible while satisfying user requirements in each section; the usage characteristics depend on the averagecopy volume and required functionalityof thecopier. If some copiers reach the end of their lives or can no longer satisfy user requirements, the manufacturer replaces them with new machines.