Connecting part geometry and cost for metal powder bed fusion

Abstract

Additive manufacturing processes have enabled the production of parts with complex geometry. In addition, novel design approaches such as generative design and crowdsourced design challenges enable the rapid generation of many feasible design alternatives with similar functionality but distinct geometry. In this study, we use an illustrative example, focused on laser-based powder bed fusion of metals, to explore how geometry and topology differences among parts with the same functionality can drive differences in cost. To accomplish this, we utilize a process-based cost model that can account for how variations in part geometry of different design alternatives impact the cost of the additive manufacturing process and associated post-processing operations. The cost model identified differences of up to 14% between the least and most expensive design alternatives. Part mass and build time were the most influential factors to group different design into relatively similar cost groups. High part complexity was associated with lower part cost, and was not strongly correlated to reject rates. Comparing designs within these groups showed several conflicting factors such as additive manufacturing and post-processing scrap and reject rates, which were geometry dependent. This result highlights the need for methods to better understand and quantify the effect of part geometry on manufacturing outcomes related to cost, including powder usage, post-processing requirements, and failure rates. Such methods can help designers to weigh tradeoffs between different cost, sustainability, quality, and performance objectives to select a preferred design alternative.