REM has, in Phase 1, proven concept and fully developed a combinatory surface finishing process optimizing Chemical Milling and Chemically Accelerated Vibratory Finishing capable of uniformly removing .020” in less than 24 hours from the surface of Additively Manufactured (AM) Inconel-625 components, fabricated by selective laser sintering and by powder blown direct energy deposition. The as-processed components shown improved mechanical performance over the as-built components. Building upon this 100% deliverable success in Phase 1, in Phase 2 we will: optimize processing parameters further for the Optimal Finishing Technique (OFT); conduct additional testing to validate resultant fatigue and mechanical improvements; conduct testing to validate non-reactive surface phenomenon discovered in Phase 1 during chemical milling, in which processing imparted near total IN-625 surface chemical resistance; begin processing AM IN-625 components in geometries useful to NASA and commercial parties; adapt and optimize OFT for other AM Nickel-based Superalloys (NBS) (IN-718 and AM Hastelloy-X) specimens and components; design, build, and implement in-house OFT processing system capable of safely, cleanly, and efficiently (scalable and with minimal operator interaction) processing commercial and NASA AM components. Design of said in-house system will include internal neutralization tanks for reactive/toxic chemistries and scrubbers/covers for remediation of hazardous fumes such that there is no operator or environmental contact during processing. Ultimately, beyond Phase II, this system will be further optimized for fully scalable installation capabilities at NASA and/or customer locations to allow for processing of 100s or 1000s of components safely in situ.
The OFT impacts NBS AM parts for improved surface finish/mechanical property: nozzle, missile body, rocket skin(X-15), nuclear reactor, turbomachine parts(blisks, stators), stud supports, thrust chamber(F-1), engine manifold(Merlin), rocket engine(SuperDraco). Non-AM NBS parts are also impacted. NBS value is wide for NASA, due to mechanical strength, resistance to thermal creep deformation, surface stability, and corrosion/oxidation resistance. A drawback of NBS is cost; AM reduces cost provided that parts meet quality/reliability standards.
The OFT will be useful for all AM NBS applications. Other government agencies will benefit, including the DOD. Also, the aerospace, energy, oil and gas, naval and chemical processing industries will have use for the OFT in applications such as combustion chambers, compressor vanes, fuel nozzles, impellors, and exhaust ducts. REM is already working with many these industries.