Cold spray forming: a novel approach in cold spray additive manufacturing of complex parts using 3D-printed polymer molds

The solid-state additive manufacturing (AM) process cold spraying (CS) offers advantageous properties such as melt-free near-net-shape part fabrication and high deposition rates. Compared to other metal-based AM processes such as the powder bed fusion of metals (PBF-LB/M) or directed energy deposition (DED) processes such as laser metal deposition (DED-LB), CS features lower part resolution. One solution to increase the achievable level of detail is spraying onto removable molds. No study exists that investigates the general feasibility and manufacturing boundaries, from which design guidelines could be derived. In this paper, the applicability of material extruded and thermally bonded polymer (MEX-TRB/P) shapes, which is especially suitable for flexible low-cost production of small batches, as molds for cold spray additive manufacturing (CSAM) is investigated. For this purpose, material extruded thermoplastics are examined regarding their suitability for the CS process. Furthermore, geometrical and thus constructive restrictions of this new approach "Cold Spray Forming" (CSF) are analyzed using an industry-relevant use case. It was shown that the feasibility of this approach could be determined by the material value hardness of the sprayed polymer substrates.