An Approach to Compare Sustainability Performance of Additive and Subtractive Manufacturing During Process Planning

Additive manufacturing is a family of processes that has been gaining attention recently by industry, researchers, and policy makers. Many claims have been made about improved sustainability performance over traditional subtractive machining processes. However, these claims have not been substantiated through sustainability characterization. This paper presents a method to compare several sustainability metrics for parts of varying size produced by additive and subtractive manufacturing processes. The production of a part is modeled using direct energy deposition (DED) as the representative additive process and milling as the representative subtractive process. The results indicate that milling has superior performance than DED when relatively small volumes of material are removed from an initial workpiece. As more material is removed by milling, the difference between the performance of DED and milling decreases. With increasing material removal volumes, DED becomes the superior process from a sustainable manufacturing perspective. This research gives decision makers a demonstrated approach and selection windows for the superior process type for a given workpiece design and preselected sustainability assessment metrics.