Internal/External Surface Finishing of Additively Manufactured IN-625 Components

The objective of this proposal is to develop a surface finishing technology for Inconel 625 Additive Manufactured (AM) workpieces.   The following methodologies will be evaluated and optimized: vibratory finishing, chemical milling and electropolishing.  Once optimized, the project will explore combinations of these aforementioned methodologies in order to identify a surface finishing process that can remove 0.02 inches (0.51 mm) of stock in the shortest practical time.  The deliverable will be a practical surface finishing procedure that is amenable to commercial industrial scale-up.Inconel 625 is a nickel-based superalloy that is used in critical aerospace parts that require mechanical strength, resistance to thermal creep deformation, surface stability and resistance to corrosion or oxidation.  AM Inconel 625 parts are lighter, can be more complex and consist of fewer components than those made by conventional machining.  AM parts, however, suffer from very rough surfaces having initiation sites that lessen their mechanical strength and fatigue properties.  A process is urgently needed to reduce the surface roughness so as to eliminate stress raisers in order for the aerospace industries to take full advantage of AM Inconel 625.  Currently, there are no known processes to accomplish this proposal’s objectives.