Developing a set of sustainability indicators for product families based on the circular economy model

Currently, design for sustainability is a necessary issue in any product development process. This situation is due to the existing and increasing pressure under industrial activities that follow a linear economy model based on design, manufacture, use and final disposal. As a feasible solution, Circular Economy (CE) model is considered a key strategy to enhance the overall sustainability performance of products, including strategies to improve the useful life of products and close flows of material in a circular path. In the measurement of circularity, existing sustainability indicators are oriented solely to single products and do not consider the product family approach, which involves the use of a common product platform comprised by constructive components or modules able to generate different product variants to satisfy a variety of customer requirements. Consequently, this paper proposes six indicators regarding material flow, reusability, reconfiguration, and functional performance. Such indicators are focused on measuring the circularity of product families respect the circularity of components among their product variants. A case study based on a family of prosthetic fingers is developed to demonstrate the implementation and usefulness of the proposed set of indicators.