High Flow Differential Cleaning

NASA developed this High Flow Differential Cleaning technology in response to in-house needs for a more automated and effective method to remove stubborn particles from complex parts fabricated using powder-bed-fusion equipment. The invention uses a large volume of pressurized air to quickly enter a cleaning chamber. Based on the Bernoulli principle and Continuity equation, the high flow results in significant air velocity and a decrease in pressure when airflow passes through smaller component orifices, which in turn removes remnant powder from the part. In one embodiment, the invention consists of a (1) high-pressure air compressor with ISO 8573 Class 2 drying capability, (2) a large pressure chamber with a fast-actuated valve system to, (3) a cleaning chamber containing various sensors, injection systems, (4) a test fixture designed for easy orientation adjustments, and (5) an expansion chamber allowing air to expand and drop in velocity, particles to settle, and filtered air to re-enter the room. This NASA technology can be implemented as a standalone cleaning system for powder bed fusion additively manufactured parts, or could be integrated into a packaged post-processing system offering. CT scans of complex NASA parts cleaned using a proof-of-concept system based upon the invention revealed very promising results. NASA welcomes industry to test the cleaning speed and efficacy of the technology under an evaluation license. Powder-based AM methods typically require post-fabrication component cleaning to remove residue powder from the surface and crevices of the part, a task that becomes increasingly difficult and time consuming with part complexity. Methods currently available to clean AM parts have significant drawbacks. Immersive cleaning using solvents or solutions can cause powder clumping. Forms of blasting (e.g., wet, bead, hydro, bristle, vacuum, etc.) work on line-of-site surfaces but are ineffective for recessed cavities. Such cleaning is typically manual, highly time consuming, and requires careful use of personal protective equipment to avoid powder inhalation. Thus, the AM market would benefit from a more automated, rapid, and effective method for cleaning complex parts.