Accounting For Product End-of-Life Status in Disassembly Time Estimation Using Modified Maynard Operation Sequences

Design for disassembly (DfD) approaches play a vital role in (re)designing products from improving their sustainability and circularity performance. This is particularly true in the case of complex resource-intensive products wherein material recovery and reutilization at their end-of-life (EoL) is dictated by the ease-of-disassembly. Various DfD approaches have been developed for increasing recovery of valuable materials by reducing the overall disassembly time (DT). However, such methods do not consider the actual EoL status of a product while estimating DT. The lack of a systematic approach for adjusting DT based on the EoL product status (e.g., fully operational product, presence of functional failures in specific parts, missing parts) prevents current DfD approaches from accurately assessing DT and can therefore lead designers towards solutions that reduce the overall sustainability and circularity performance of products. To address this gap, the proposed study develops an approach that can account for EoL product status during DT estimation of DfD scenarios during early design. The central idea of this approach is modifying standardized motion sequences for disassembly operations based on potential failure modes in a product's EoL. The proposed approach was tested on a real case study involving an electrical kettle. Results show the proposed approach can generate new insights regarding product disassembly performance. In particular, some Failure Modes can lead to a reduction of DT due to changes in disassembly action type and the corresponding product EoL scenario (i.e., from reuse to disposal). In such cases, a reduction in DT can be counterproductive from a circular economy perspective as the gains result from a diminished ability to recover/reuse products.