Pergamon Computersind. Engng Vol.35, Nos 1-2, pp. 65-68, 1998 © 1998 Elsevier Science Ltd.Allrightsreserved Printedin GreatBritain Pll: S0360-8352(98)00021-7 0360-8352198$19.00+ o.oo High-mix/Low-volume Batch of Electronic Equipment Disassembly Pitipong Veerakamolmal and Surendra M. Gupta* (*Corresponding Author) Laboratory for Responsible Manufacturing 334 Snell, Department of MIME Northeastern University 360 Huntington Avenue Boston, MA 02115, U.S.A. E-mail: gupta@~neu.edu ABSTRACT This paper presents a procedure to disassemble electronic products with multiple subassembly modules. First, a partial schedule for each subassembly is obtained. The next step modifies the partial schedule in order to minimize the machine idle time at the retrieval process and, thus, the resulting makespan of the whole process. The procedure offers an optimal process makespan according to the sequence in which the batch of products pass through the disassembly and recovery processes. Special emphasis is placed on applying variant process planning methodology for disassembly and retrieval. © 1998Elsevier Science Ltd. All rights reserved. INTRODUCTION New electronic products are usually compact and equipped with the latest technology. They are replacing outdated ones at an astronomical rate. Ironically, a large number of outdated products are often in excellent condition. Rapid product development, coupled with consumer appetite for latest models of products, have caused consumers to discard outdated products even though they are still operational. This leads to an increase in the quantity of used and outdated products scrapped. Economically justified, products made with reusable components, retrieved from the electronic products, are sometimes not only cheaper but also better. For example, electronic chips recovered from outdated computers and reassembled in the production of toys could prove to be more reliable than the new chips, because the reused chips would have survived the "bum-in" period. In addition, because retrieved parts are often classified as scrap, manufacturers could obtain them at a below-market cost. Considerably higher profits would be realized if the request to retrieve those reusable parts and materials can be facilitated in lots. This paper proposes a recovery system that integrates the disassembly and the component recovery processes in one domain, called the Integrated Component Recovery System (ICRS). The ICRS model is developed to address two coherent subsystems, viz., the disassembly facility and the component retrieval facility. Both subsystems are linked by a material handling carrier that transports one disassembled item after another, from the first to the second subsystem. The first subsystem handles the disassembly process where each batch of products is disassembled to obtain the Printed Circuit Boards (PCBs). After each disassembly operation, the PCBs obtained are passed on to the component retrieval facility where the retrieval process is carried out. The retrieved components can then be redistributed to manufacturers, while the leftover materials can be sent for recycling or proper disposal [8] (Figure 1). Because the model encompasses two distinct operations, one that disassembles PCBs from the products, and another that retrieves electronic components from the PCBs, the scheduling of the two subsequent processes increases the complexity of the model. A solution approach is required to schedule the operations in both processes to optimize the aggregate makespan. Since the incoming supply and mixture of products are presumably high-mix/low-volume, the scheduling and sequencing approach must be robust and flexible. 65