Design and Pathway Programming of Freeform Thin-walled Geometries Produced by Laser Metal Deposition

Laser metal deposition (LMD) shows great promise for producing large components as well as thin-walled structures by additive manufacturing. Compared to the powder bed fusion (PBF) techniques, LMD can exploit further flexibility in terms of tool path programming. Layer-by-layer rastering commonly used in SLM is applicable also to the LMD process, where overhang structures remain a complex issue in the absence of support structures. Concerning thin-walled parts with a symmetry axis or those that evolve around an axis, more efficient strategies may be developed. Hence, this work discusses the use of different part programming strategies for thin-walled structures employing an LMD system based on a 6-axis anthropomorphic robot and a 2-axis rotary table. The work compares, layer-by-layer, continuous pathway, and oriented reference plane strategies, study of process parameters, build failure mechanisms, as well as geometric errors are discussed. Successful deposition of thin-walled organic and freeform tubular components in AISI 316L is demonstrated.