A systematic selective disassembly approach for Waste Electrical and Electronic Equipment with case study on liquid crystal display televisions

Abstract

Waste Electrical and Electronic Equipment (WEEE) is one of the major waste streams in terms of quantity and toxicity, and a critical step in WEEE end-of-life (EoL) processing is through disassembly. Compared with full disassembly, which is a sub-optimal solution due to its high operational cost, selective disassembly is more economic and practical as only selected parts with recycling potential are considered. In this paper, a systematic selective disassembly approach for handling WEEE with a maximum disassembly profit in accordance to the WEEE and Restriction of Hazardous Substances (RoHS) Directives has been developed. Firstly, a space interference matrix is generated based on the interference relationship between individual components in the 3D CAD model of WEEE. A matrix analysis algorithm is then applied to obtain all the feasible disassembly sequences through the obtained space interference matrix in a 3D environment. Secondly, an evaluation and decision-making method is developed to find out an optimal selective disassembly sequence from the obtained feasible disassembly sequences. The evaluation takes into account the disassembly profit and requirements of the WEEE and RoHS Directives, which regulate on recycling rates of different types of products and removal requirements of (i) hazardous, (ii) heavy, and (iii) high-value components. Thus an optimal solution is a selective disassembly sequence that can achieve the maximum disassembly profit, while complying with the WEEE and RoHS restrictions based on a brute-force search method. Finally, an industrial case on Changhong Liquid Crystal Display Televisions (LCD-TVs) of the type LC24F4 is used to demonstrate the effectiveness of the developed approach.

Interlocking Problem in Automatic Disassembly Planning and Two Solutions

“…The sequential disassembly plan as shown in Table 1 is obtained by using the conventional sequential disassembly method [4,5] based on the space interference matrix (Appendix). As shown in Table 1, there is no removable part identified at iteration 7, and parts B, C1-2 and D are interlocked.…”

“…Jin et al [4,5] demonstrated a method based on the space interference matrix to find removable components to generate feasible disassembly sequences. The key point of this method is to find removable components which have freedom in at least one direction.…”

“…For example, it might be confused whether an object in press-fit component should be categorised as a fastener or a general part. Jin et al [4,5] proposed another matrix-based method in which the relationships of components were described by just a matrix.…”

An improved multi-objective discrete bees algorithm for robotic disassembly line balancing problem in remanufacturing

“…The disassembly model is always built by graph-based method [47,48], Petri Net method [49] and matrix-based method [50,51], etc. For robotic disassembly, feasible disassembly direction of each part should be provided for industrial robots.…”

Robotic disassembly sequence planning using enhanced discrete bees algorithm in remanufacturing

“…Considering the changes of disassembly tool, the changes of disassembly direction, the part volume and the maintainability, Kheder used genetic algorithm to obtain optimal disassembly sequence of a rear axle (Kheder, Trigui, and Aifaoui 2015). To disassemble heavy, hazardous and high-value components as early as possible, brute-force method was proposed to obtain the optimal disassembly sequence based on waste electrical and electronic equipments (Jin et al 2015). To simultaneously optimize the disassembly level, recovery options and disassembly sequence, an improved co-evolutionary algorithm was used to find the optimal disassembly solutions (Meng et al 2016).…”