Electrochemical-Based Surface Enhancement of Additively Manufactured Ti-6Al-4V Complex Structures

Abstract

Poor surface quality has long been a significant challenge to the broad adoption of additive manufacturing (AM) in industry. This work deploys a customized electropolishing (EP) procedure to improve the surface finish of complex laser powder bed fusion Ti-6Al-4V parts with internal channels and various geometries using a substantially less hazardous, anhydrous, alcoholic solution, while maintaining the geometrical fidelity of the parts. A preliminary study on simple geometries was run to evaluate the effect of EP time on surface roughness and thickness loss of a part. By using a customized test setup and an artificial EP waveform to accurately control EP parameters, a high EP efficiency was achieved (maximum reduction of surface roughness up to 70% and a minimum thickness loss of 11%) with low treatment times. Subsequently, EP was conducted on the internal surfaces of various geometries in increasing order of complexity; the results showed the effectiveness of the proposed technique across different geometrical features, leading to maximum uniform surface roughness improvement of 77% with minimum thickness loss of only 7%. The proposed methodology from this work for a fast and cost-effective surface enhancement methodology in an environmentally safe solution may be used on real, complex AM parts to enhance both internal and external surface quality.