Advancements in surface finish for additive manufacturing of metal parts: a comprehensive review of plasma electrolytic polishing (PEP)
Joško Valentinčič, Jithinraj Edaklavan Koroth, Henning Zeidler
Abstract
Additive manufacturing (AM) has become a popular technique for producing metal parts due to its design flexibility, shorter lead time and lower material consumption. However, the higher surface roughness of printed parts limits their direct industrial use. Over the years, many post-processing techniques have been developed, such as laser polishing, chemical and electrochemical polishing, mechanical polishing, electro- discharge techniques, conventional machining and so on. Plasma electrolytic polishing (PEP) is a relatively new and popular method for post-processing AM parts. This comprehensive review highlights the potential of PEP to achieve shiny surfaces in an efficient and environmentally friendly way and to overcome the challenge of surface finishing in AM. This article examines the research developments in PEP for metal AM parts, materials studied, impact on material properties, application to unique AM features such as lattice structures and up-skin/down-skin properties and the challenges and limitations of the process. In addition, this article discusses the future prospects of PEP, including opportunities for automation, standardization and numerical modelling to expand and explore the impact of PEP on AM parts. Furthermore, this study demonstrates the importance of PEP in improving AM parts in various industries and providing a sustainable solution for better surface quality.