Surface finish of AM parts by Plasma electrolytic Polishing

Additive Manufacturing (AM) is considered a key enabling technology because of its capability to create complex shaped parts directly from CAD data without the need for specific molds, tools or dies [1]. Especially when applying powder- bed-fusion AM, industrial requirements regarding mechanical strength and overall accuracy can now be satisfied. However, the surface achievable is not sufficient for many applications. Finishing processes are therefore critical; due to the complexity of the parts, conventional technologies are difficult to apply. Plasma electrolytic Polishing (PeP) could be a suitable process, since it does not require a shaped tool. It is based on a high DC voltage applied between a metallic part and an aqueous electrolyte and the following creation of a plasma envelope around the part. There, electrochemical and plasma reactions take place, ablating material and reducing surface roughness. It has the capability of achieving surface quality of Ra ≤ 0.02 µm [2]. PeP is well suited for deburring, shining and polishing of complex shaped parts. PeP is a suitable process to finish macro- as well as micro parts and contributes to a tight tolerance chain. Applied on AM parts, it is allowing to push the design of complex parts further towards general industrial use. The paper presents the current state and appli- cation scenarios as well as ongoing research topics.