Product miniaturization is an ever increasing customer demand in aerospace, bio-medical, defense and electronics industries. These microparts play a vital role and are required to abide by stringent norms set forth by various quality control agencies. To maintain their functionality over a period of time, they are made of special engineering materials rather than silicon as commonly used in microelectronics. Lithography, etching, embossing, electroplating, laser machining and other micro manufacturing techniques have been employed traditionally to manufacture microcomponents; however, these techniques would be expensive, cause surface damage, or produce a very rough surface. Electrochemical polishing is capable of machining/polishing any conducting material while holding close dimensional tolerances. This research develops a high frequency electrochemical nanopolishing technique for commercially pure alpha titanium. An alcohol and salt based electrolyte was used with direct current as well as alternating current on alpha titanium plate. For both current types, optimal surface roughness R_(a) ~ 300 nm was obtained on poly grained surface using interferometry and ~ 2 nm within a single grain by atomic force microscopy. Comparable results were obtained by other researchers with 30-120 nm R_(a) for titanium and titanium alloys. Linear regression models were developed to predict the surface roughness. The surface roughness predicted by the models was found to be within 26% of the measured values.

Selective laser melting has shown incredible growth as a metallic additive manufacturing process in recent years. While it does provide many solutions and new ways to approach challenges, it does not come without issues of its own, namely, surface roughness. In the as-printed state, the surface roughness of selectively laser melted parts is unacceptable for use in engineering applications. Additionally, selective laser melting is used to produce complex geometries with hard to reach features, preventing conventional mechanical polishing from being successful. Therefore, it is necessary to evaluate non-mechanical polishing processes as treatments for surface roughness. In this study, electrochemical and laser polishing were investigated as potential start-to-finish treatments for the surface roughness of selectively laser melted parts. Following this preliminary study, a follow-up study investigating the effect on the mechanical strength of a lattice design that electropolishing would have. Electropolishing was found to significantly reduce the surface roughness of the as-printed part, but not to a usable value. Additionally, electropolishing was found to be unacceptable for use on lattice parts. Laser polishing was found to significantly reduce the surface roughness of the part but had feature size issues preventing a perfectly smooth surface.

This diploma thesis deals with the surface modification of 3D printed metallic materials. The research part presents the most used methods of additive manufacturing and their process parameters influencing the quality of printed components. Defects arising during these processes and the techniques used to eliminate them are also described. In the experimental part of the work, the optimization of electrochemical polishing parameters was performed. The aim was to modify the rough surface of the components and thus prevent the formation of defects on the surface. The mechanical properties were investigated by means of three-point bending under static and dynamic loading. Fractographic analysis was performed on the quarry surfaces.