Micro-Geometrical Evolution of Titanium Surfaces by Dry Electropolishing

Dry electropolishing is a metal finishing process that employs an ion transport mechanism through co-polymers particles retaining a small amount of sulfonic or metanosulphonic acid. It offers advantages over traditional liquid electropolishing, such as reduced chemical waste, more uniform polishing, and no part shape variation. The tuning of the process parameters is still challenging, and an in-depth investigation is necessary to evaluate their effect on the surface morphology. The work analyzes the micro-geometrical evolution of the profiles through a particular alignment of periodical surfaces taking into account different starting morphologies and investigating the effect of the processing current times. Morphological analysis is addressed to the understanding of the crucial role played by the initial roughness on the electropolishing capability, especially in the case of Additively Manufactured surfaces characterized by strong anisotropy. A statistical modeling of the roughness percentage reduction is developed to determine a relationship with the investigated factors. Sets of favorable combinations of processing parameters are found on simple geometry and applied to a case study characterized by curved and intricated internal surfaces.