Speaker
Description
Additive Manufacturing (AM) has opened new frontiers in the fabrication of complex components for accelerator applications. However, the surface roughness of as-built parts remains a key challenge, particularly for high-frequency RF and vacuum environments. Plasma Electrolytic Polishing (PEP) is emerging as a promising post-processing technique to address this issue.
PEP is an electrochemical technique that uses high voltage (250–350 V) and moderate current densities in heated electrolytes to polish metallic surfaces. A key feature of the process is the formation of a vapour-gas layer at the anode surface, which enables efficient and uniform material removal without mechanical contact. The result is a smooth, reflective finish, with typical material removal rates between 4 and 30 μm/min.
The PEP operates by immersing the component - configured as the anode - into a heated electrolyte bath maintained at approximately 60-90°C. A dynamic formation of a vapor-gas layer (VGL) around the part plays a fundamental role, resulting in a dramatic reduction in roughness and a highly reflective, mirror-like surface finish.
At INFN-LNL, we have applied PEP to a variety of AM-fabricated materials and geometries relevant to accelerator technology. In this contribution, we report on the most recent experimental results obtained from the PEP treatment of benchmark stainless steel samples, inner copper conductors, and copper drift tubes designed for LINAC structures.
