Abstract
Most developed countries started to enforce environmental protection regulations due to the recent green consciousness. The European Unions (EU), among them, has passed two strict directives, WEEE and RoHS, which restrict the amount of hazardous substances in the product and the recycling/reuse rates in product end-of-life, respectively. These regulations significantly impact development of the products exported to the EU. Thus most international brands have to take special procedures in the product development for compliance with the green directives. Previous studies indicate that product disassembly sequence is a key factor in green product development. It must be taken into account at the design stage. This research investigates disassembly of 3D product with focuses on three topics: “disassembly planning of single part”, “calculation of the part precedence relationship”, and “optimization of disassembly planning”. First, a novel method is proposed to construct a progressive path planning network for part disassembly. The nodes in the network are determined by intersecting a series of cutting planes and the obstacle space. The disassembly path is then computed by incrementally moving the part within consecutive cutting planes. The calculation efficiency is improved without the need of the entire network construction. This work also presents an approach for concurrent disassembly of two parts without interference. In the part precedence relationship, the Octree technique is applied to characterize the spatial relationships among the parts comprising a product. Integrated with PSO (Particle Swarm Optimization) algorithms, the result allows optimization of the product disassembly sequence while considering the recycling rate, the reuse rate, and the disassembly costs. The proposed methods provide effective means for computer-aided green product design, which facilitates disassembly planning, reduces disassembly cost, and thus achieve sustainable product development.