By Mark Norfolk on Monday, February 1st, 2021
Fabrisonic has consistently proven the ability to create quality, hermetic heat exchangers with complex internal geometries using Ultrasonic Additive Manufacturing (UAM). These heat exchangers have even endured NASA Jet Propulsion Lab’s harsh testing criteria. However, these parts have almost exclusively been printed on Fabrisonic’s larger machines like the SonicLayer® 7200. Until now…
Fabrisonic’s recent inception of the SonicLayer® 1200, with a smaller work envelope of 10” x 10” x 10”, has presented new opportunities for customers looking to utilize UAM. One recent opportunity is a Utah State University’s College of Engineering project in which Fabrisonic was contracted to print 6061 aluminum satellite heat exchangers roughly 4” x 4.5” x 0.6” in size. Initially, these heat exchangers were printed in a larger machine to yield fully hermetic heat exchanger units, but Fabrisonic quickly realized that these parts were the perfect opportunity to test the SonicLayer® 1200’s ability to print complex channel geometries. The SonicLayer® 1200, being smaller, allows for more affordable production.
The heat exchanger CAD models above depict the complicated fluid passages running through these heat exchangers. To create these channels, slots were CNC machined using the subtractive portion of the hybrid (additive & subtractive) system before being filled with Fabrisonic’s patent pending support material. With the support in place, channels can be sealed without metal extruding into the cavities. In a simple post processing cleaning operation, the support material is washed out to leave smooth and dimensionally accurate fluid channels. This project is the first opportunity in UAM history for the patent pending support material to be used in the SonicLayer® 1200 for printing heat exchangers.
With the internal channels complete, the part was printed to net shape then machined to final dimensions in place. With geometric dimensions and features matching the model, the next step was to ensure the heat exchanger was fully functional and leak proof. For this part to perform its role on the satellite, it must be hermetically sealed to prevent refrigerant leakage into the vacuum of space.
To validate seals of the heat exchangers, the units were submerged in a tub of water, and channels were pressurized to 50 psi. If any air bubbles escaped to the surface of the tub, then we knew that the channels were not hermetic. In UAM fashion, all parts passed this test and are now on their way to final testing at Utah State University where a sensitive helium leak detector will be used to simulate the vacuum of space.
These heat exchangers proved that the much smaller, more affordable SonicLayer® 1200 can produce the same parts as the large SonicLayer® 7200 with similar quality. The results from Utah State University will determine just how well these small exchangers can perform, and whether they have what it takes to survive in space!
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