A Holistic View on Sustainability in Additive and Subtractive Manufacturing: A Comparative Empirical Study of Eyewear Production Systems

To achieve sustainability across the product life cycle, attention to the production process is a prerequisite. As a result of technological advancements, innovation and inventions in production methods are in full swing. Production methods that enable mass customisation (MC) are one of the recent developments in the production domain. This study aims to empirically explore the sustainability impact of two MC-oriented production methods, namely, additive manufacturing (i.e., Selective Laser Sintering) and subtractive manufacturing (Computer Numerical Control Milling) within two complete production lines (i.e., from raw material to assembly) for a wearable product. In the context of the triple bottom line framework, the production lines are analysed from an economic, environmental, and social standpoint. A Discrete-Event Simulation (DES) is used to quantify and compare both production systems with their inherent variability in a dynamic setting of fluctuating order volume and diversity. The findings of the simulation are qualitatively evaluated using expert interviews. This study provides a detailed insight into several sustainability trade-offs in production systems where additive and subtractive manufacturing are involved.