Classifying Multi-generational Products for the Circular Economy

Manufacturers are increasingly interested in the circular economy (CE) and potential of circular productions. To fully utilize CE, better guidance at the design stage is needed to establish closed-loop flows and prioritize higher value retaining end-of-use (EoU) practices such as reuse and remanufacture (i.e., parts harvesting). Intergenerational commonality (IC) is a method to increase EoU parts harvesting. However, closed-loop parts harvesting potential depends on the compatible timing between design generations' production and EoU returns curves. Therefore, in this paper, we explore an approach to make an initial assessment on where IC as a closed-loop CE strategy can produce most benefit, where such closed-loops may fall short, and what favorable design decisions can be made. The proposed indicator (based on the ratio between product's average usable lifetime and time between generation introductions, u_avg/t_intro) provides a basis for developing an objective design-support tool. Using a hypothetical example, we discuss the approach and effectiveness of this indicator. The insights gained suggest that overall production's sustainability performance show substantial improvement when u_avg/t_intro < 1.25, and the IC benefits are highest when 0.25 < u_avg/t_intro < 2.0. We also highlight a few managerial insights gained from the indicator useful to strategize EoU recovery and IC.