Electrochemical Polishing of Ti-6Al-4V 3D Printed Internal Channels with Customized Functionalized Cathode Using HF and Perchlorate Free Electrolyte

This study aimed to achieve a polished surface on the internal channel of Ti-6Al-4V, a popular titanium alloy in the 3D printing industry, using electrochemical polishing (ECP). We used a custom functionalised cathode and less toxic electrolyte to achieve this goal. We found that a smooth surface with a minimum roughness of Ra value 9.9 µm could be achieved, and localised polishing of channels could be done without masking the workpiece itself. The study investigated the interaction between the workpiece, cathode, and electrolyte within the internal channel and found that the formation and removal of a viscous layer during ECP affected the polishing effect, as well as the bubbling produced at the cathode. The optimal process parameters are expected to vary for different geometries and could be determined through a linear sweep voltammetry test followed by ECP at a constant voltage. This research provides useful insights and methods for achieving ECP on the internal surface of Ti-6Al-4 V components which could have significant implications for the design of more complex components for applications of 3D printing in the aerospace, marine or med-tech industries.