Design optimization of supports for overhanging structures in aluminum and titanium alloys by selective laser melting

Selective laser melting (SLM) process allows fabricating strong, lightweight and complex metallic structures. To successfully produce metallic parts by SLM, additional structures are needed to support overhanging surfaces in order to dissipate process heat and to minimize geometrical distortions induced by internal stresses. However, these structures are often massive and require additional post-processing for their removal. A minimization of support structures would therefore significantly reduce manufacturing and finishing efforts and costs. This study investigates the manufacturability of overhanging structures using optimized support parts. An experimental study was performed to identify the optimal self-supporting overhanging structures using Taguchi L36 design. Experimental results revealed that with optimized supports it is possible to build non-assembly mechanism with overhang surfaces. However, it is necessary to correctly orientate the part in the SLM machine in order to build it with a minimal support structure so to obtain the best trade-off between production time, cost, and accuracy.