Description: REM has, in Phase I and II, proven concept and fully developed a combinatory surface finishing process optimizing Chemical Milling and Chemically Accelerated Vibratory Finishing (the “OFT”) capable of uniformly removing 0.020” in less than 24 hours from the surface of Additively Manufactured (AM) Nickel-based/Iron-based superalloy (NBS and FeBS) components, fabricated by laser powder bed fusion and by laser blown powder direct energy deposition as well as developed a prototype processing cell expanding component size processing capabilities from 6x6x 6” to 30x30x24”. The OFT-processed components demonstrated improved performance over as-built and alternatively surface finished technologies in mechanical testing. Further the OFT has shown efficacy on actual nozzle and combustion chamber hardware as a part of the RAMPT project including hot fire testing of the LLAMA rocket engine featuring OFT processed components. However, further scaling the OFT for larger parts is challenging given greatly increased capital expenditure and processing costs. This II-E addresses these hurdles and will develop the capability of processing larger rocket engine components. Building upon the 100% deliverable success in Phase II, in Phase II-E REM will: design, construct, & test a large-scale processing apparatus; validate/optimize the OFT for this apparatus; utilize this large-scale processing apparatus and validated OFT to surface finish one 100K nozzle, one 65% RS-25 nozzle, and one component of similar size and complexity to the 100K nozzle to be defined by AFRL. The processing apparatus will include all necessary chemical and fume handling/extraction equipment to ensure the safety of operators and compliance with all environmental regulations. Beyond Phase II-E, this system will be further optimized for fully scalable installation capabilities at NASA and/or customer locations to allow for processing of large-scale components at 3rd party locations.

Benefits: The OFT and apparatus are vital to NASA’s LBP-DED rocket engine building initiatives which require hot wall thickness reduction and surface/near surface roughness/flaw remediation. Applicable components include: nozzles, combustion chambers, missile bodies, turbomachinery components, and structural components. The apparatus will be material agnostic, so potential applications are not limited to NBS/FeBS components.

The OFT and apparatus will be useful for all AM applications. Other government agencies will benefit, hence AFRL’s investment. The space, aerospace, energy, oil and gas, naval and chemical processing industries will have use for the OFT in applications such as nozzles, combustion chambers, turbomachinery components, impellors, and exhaust ducts. REM is already working with these industries.