Application of contactless support for overhang fabrication in the L-PBF process of Ti–6Al–4V ELI

Support structures are widely used in laser powder bed fusion (L-PBF) to fabricate overhang geometries; however, their removal increases manufacturing time, cost, and the risk of surface damage. This study systematically investigates the effectiveness of contactless support for Ti-6Al-4V ELI overhangs, focusing on its role in heat dissipation without physical contact. Overhangs with various inclination angles were evaluated in terms of surface roughness, thickness deviation, microhardness, and microstructural characteristics. The results show that contactless support improves surface quality and dimensional fidelity by enhancing heat transfer through the powder layer. The gap distance was identified as a critical parameter governing thermal behavior, with optimal values depending on overhang geometry. Excessively small gaps caused unintended bonding, whereas large gaps reduced heat transfer efficiency. In addition, reducing support thickness led to only marginal degradation in overhang quality despite significant reductions in material usage and build time. Overall, contactless support provides an effective thermal pathway without physical contact, and its performance can be optimized through appropriate design of gap distance and support thickness.