J. Boykin, R. Shealy
REM Surface Engineering,
United States
Keywords: additive manufacturing, internal channels, postprocessing, surface finishing, powder blockage removal
Summary:
Metal Additive Manufacturing (AM) is transforming component fabrication, enabling the production of complex structures such as heat exchangers, integrated cooling channels, and lattice structures that are difficult or impossible to create using traditional methods. Laser Powder Bed Fusion (L-PBF), a leading AM process, has opened new possibilities for design and performance. However, several challenges hinder the full realization of AM’s potential. One significant issue is the removal of powder from internal channels and cavities. Current methods are often manual, costly, and unreliable, especially for highly complex components. In some cases, powder removal is impossible, leading to the scrapping of expensive parts and wasted manufacturing hours. This constraint forces designers to modify optimal designs, limiting the advantages of AM. Additionally, as-printed components typically exhibit high surface roughness and surface-related defects (SRDs), including near-surface porosity. These defects can impair fluid flow, increase risks of foreign object debris (FOD), and reduce fatigue resistance. For thermal transfer applications, achieving optimal wall thickness is another limitation of current AM technologies, affecting performance and lightweighting efforts. To overcome these limitations, REM is developing a chemical process aimed at addressing key challenges in AM. This process will allow for controlled powder removal from internal channels and cavities, reducing reliance on manual methods. Furthermore, it will significantly improve surface quality by reducing roughness and eliminating SRDs, ensuring better mechanical properties and reliability. The technology will also enable uniform wall thickness reduction, allowing components to be printed with optimal manufacturability and subsequently thinned to enhance thermal transfer and reduce weight. The benefits of this process are particularly relevant to the aviation industry, where AM can address sustainment challenges related to a dwindling supply base, high costs, and long lead times for legacy components. By reducing operational steps and improving efficiency, AM has become a critical technology for defense readiness and operational availability goals. However, its adoption has been slowed by challenges such as poor surface quality and the detrimental effects of SRDs on mechanical performance. These issues prevent simple “like-for-like” replacement of traditionally manufactured components. REM’s chemical process seeks to unlock the full potential of AM for both defense and commercial applications. By ensuring reliable powder removal, reducing surface roughness, and addressing wall thickness limitations, this technology will support advanced component manufacturing for critical areas such as hypersonics and other strategic applications. It will also enhance the performance and durability of AM-produced components, making the technology more viable for a wide range of industries.