Smoothening of the down-skin regions of copper components produced via Laser Powder Bed Fusion technology

Abstract

Additive manufacturing (AM) is revolutionizing the industrial scenario. Four copper samples have been printed via Laser Powder Bed Fusion (LPBF) at DIAM Laboratory (INFN—Sezione di Padova, Padova, Italy). Samples had different geometrical characteristics, to test the feasibility of the AM as a productive technique for the creation of unsupported copper structures that are characterized by surfaces with a very small inclination angle, where supports cannot be placed. Parts have been printed successfully even in case of 18° of inclination of unsupported walls with respect to the horizontal plane, and on the same samples, surface finishing treatments (performed by Rösler Italiana S.r.l. and INFN-LNL) have been performed to reduce the roughness of the down-facing surfaces. Indeed, the down-skin regions are the most critical areas of AM parts. Several surface treatments are under investigation: mass-finishing treatments (mechanical and chemically assisted mechanical processes), chemical polishing, and electropolishing, and for some of them, the results are extremely positive: from an initial roughness (Ra) of 30–35 µm, the treatments allowed us to achieve a Ra value lower than 1 µm. The study here exposed presents a good way to rapidly reduce the roughness of 3D-printed parts, reaching a mirror-like aspect.

On the Post‐Processing of Complex Additive Manufactured Metallic Parts: A Review

“…This is typical in LB‐PBF downward‐facing (down‐skin) surfaces due to the different laser‐material interaction phenomena. [ 77,78 ] i.e., a smaller surface roughness value ( S a = 4.4 μm) was measured on the flat side of the U‐shape tube compared to the curved side ( S a = 20.6 μm). Furthermore, due to a higher degree of electrolyte agitation, the internal surface roughness of the cylinder sample after ECP was lower than the rectangular part as validated by optical and SEM images (Figure 10d).…”

On the Fabrication of High-Performance Additively Manufactured Copper Winding Using Laser Powder Bed Fusion

“…In this regard, the DA and surface quality should be optimized first. While some studies have reported the DA and surface roughness of Cu-LPBF parts [ 7 , 17 , 18 , 19 ], none have presented potential in situ solutions for improvement. Besides, the minimum spacing between features has not yet been investigated.…”