Surface Enhancement of Laser Powder Bed Fusion Ti-6Al-4V via Chemical Milling

Surfaces of metal parts additively manufactured using laser powder bed fusion (LPBF) have features that differ from other metal product forms. As-printed part surfaces include features such as overhangs, partially melted feed stock, and large peak-to-valley roughness. The presence of these features is undesirable in many use cases because they have an impact on mechanical properties, shed loosely-adhered materials, and trap chemicals and processing materials in the part surface. Removal of the as-printed surface and reduction of surface roughness can alleviate these problems. Chemical etching processes are capable of doing both simultaneously. In addition, chemical etching process are ideal for the complex part geometries that can be produced by LPBF. Titanium chemical milling process capabilities and limitations of LPBF Ti-6Al-4V parts have been studied, and progress towards producing LPBF parts with desirable surface characteristics is presented.