This study presents a framework to estimate throughput and cost of additive manufacturing (AM) as related to process parameters, material thermodynamic properties and machine specifications. Taking a 3D model of the part design as input, the model uses a parametrization of the rate-limiting physics of the AM build process – herein focusing on laser powder bed fusion (LPBF) and scaling of LPBF melt pool geometry – to estimate part- and material-specific build time. From this estimate, per-part cost is calculated using a quantity-dependent activity-based production model.
Analysis tools that assess how design variables and process parameters influence production cost increase our understanding of the economics of AM, thereby supporting its practical adoption. To this aim, our framework produces a representative scaling among process parameters, build rate and production cost.
For exemplary alloys and LPBF system specifications, predictions reveal the underlying tradeoff between production cost and machine capability, and look beyond the capability of currently commercially available equipment. As a proxy for build quality, the number of times each point in the build is re-melted is derived analytically as a function of process parameters, showcasing the tradeoff between print quality due to increased melting cycles, and throughput.
Typical cost models for AM only assess single operating points and are not coupled to models of the representative rate-limiting process physics. The present analysis of LPBF elucidates this important coupling, revealing tradeoffs between equipment capability and production cost, and looking beyond the limits of current commercially available equipment.
Financial support for this work was provided by the Ford-MIT Alliance, Edwards Vacuum, the MIT Portugal Program, the National Science Foundation Graduate Research Fellowship Program (to K. Gee) and the MIT Presidential Fellowship program (to K. Gee). This paper is based on a preprint published previously under the same title (Gee et al., 2022).
Gee, K., Kim, S.I., Quinlan, H. and Hart, A.J. (2022), "A physics-based modeling framework to assess the cost scaling of additive manufacturing, with application to laser powder bed fusion", Rapid Prototyping Journal, Vol. ahead-of-print No. ahead-of-print. https://doi.org/10.1108/RPJ-02-2022-0065
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