Enhancing Ease-of-Disassembly Tools for Electronic Products: Insights from Assessing Computer Mice

To make electronic products fit for circular economy strategies such as life extension, refurbishment, and recycling, ease of disassembly is a key design quality. Several tools are available to assess the ease of disassembly of products during the design process, such as the ease of Disassembly Metric (eDiM) and Hotspot Mapping (HSM). The eDiM method uses the time-to-dismantle as a unit for calculating the ease of disassembly. The longer it takes to reach a priority part, the lower the ease of disassembly. Hotspot mapping scores the different parts in the product architecture and ranks them on its failure rate (priority parts), activity, time-to-disassemble, embodied environmental impact, and embodied economical value. These tools help designers prioritize which parts of the product need to be redesigned to improve its circularity. The eDiM tool is quick and easy to use but is based on generic proxy times, which may not be applicable to specific fastener designs or product types. On the other hand, the hotspot mapping tool uses actual recorded times to accurately identify disassembly hotspots. Recording the time-to-disassemble is more accurate, but is also more time consuming and depends on the operator's experience. Therefore it is difficult to come up with reproducible numbers. It is crucial to find the right balance for these tools, to be able to accurately identify hotspots while maintaining the usability. In this paper, we research how to develop product-specific proxy times in order to reduce the effort required for assessing hotspots. To reach our goal, we conducted a series of experiments to measure the actual disassembly times of different computer mice, and compared them with the predictions from eDiM. The results indicate that the tools provide accurate results for the most dominant fastener type used in this type of product (Phillips screws) but largely deviate from actual results for some other common fastening techniques, such as adhesives. Consequently, generic proxy times could not be used to correctly identify the product design hotspots. The authors suggest specific modifications to the ease-of-disassembly tools to improve their applicability, thereby supporting the design of circular electronics.