Effect of Surface Finish and Post-Processing on the Fatigue Life of Additively Manufacturing Parts

In response to the need for drastic surface finish improvement on additively manufactured metal components, Voxel Innovations Inc. has developed a novel manufacturing process termed: oscillatory pulsed electrochemical machining (O-PECM). O-PECM is a heat-free, stress-free, surface finishing technique capable of producing sub-200 nm Ra roughness. In O-PECM, a thin envelope of build material is printed around the workpiece (as a direct offset of the surface) in situ with the initial AM build. Precise oscillation of the printed envelope, in combination with a flowing electrolyte bath and multi-phase pulsed voltage waveform allow for the simultaneous finishing of the surface and removal of the envelope to reveal the part in its final state. The precision oscillation allows for proximity-controlled surface smoothing, giving O-PECM a significant advantage over competing technologies when starting finish is poor. O-PECM provides significant design freedom as it is not limited by line of sight. The proposed project will 1) optimize process parameters to achieve a fine surface finish with minimal material removal, subsequently mapping material removal vs. surface finish curves, 2) develop an optimal oscillatory pattern and design rules for the metal envelope and 3) demonstrate the improvement that O-PECM imparts on component fatigue life.