Ultrasonic additive manufacturing

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The power of sound merges layers of metal foil for radiation shielding and more.

Fabrisonic 3D-printed layers of 6061 aluminum and 0.008" thick tantalum foil to show that structural components and radiation shielding can be combined into one monolithic panel.

A 3D metal printing technique using a patented ultrasonic additive manufacturing (UAM) process uses sound waves to merge layers of metal foil. This technology can manufacture complex components with features and attributes not possible through traditional manufacturing techniques.

Tantalum, a rare, ductile transition metal with a high melting point, has a high resistance to corrosion, and its high atomic number (Z) makes it useful for radiation shielding.

Satellites have long used layers of aluminum, titanium, and tantalum to create a graded-Z structure. The variation in the metals’ Z values creates an effective filter along a broad spectrum of radiation, protecting sensitive electronic components and reducing background noise for signal analysis. Generally, graded-Z shielding also will be lighter and thinner than traditional shielding.

Since UAM can easily combine dissimilar metals, Fabrisonic can 3D print structural panels with several different Z-number materials in a single component. This limits part count and eliminates complex brazing operations.

Mark Norfolk, president of Fabrisonic, says UAM scrubs off the oxides from the metal surfaces to be joined, allowing them to make a strong, metallurgical bond. With the addition of a little pressure and heat, UAM can make a strip 1" wide by almost any length, at speeds up to 300ipm. Panels as large as 6ft x 6ft can be assembled from these strips.

Because the process happens at a relatively low temperature (200°F peak for aluminum), it’s possible to embed electronics into fully dense metallic panels, such as strain gages, thermo-couples, or fiber-optic cables.

Multi-metal components, such as this copper, aluminum, and titanium laminate, can custom-tailored with UAM processes.

Metal 3D printing technologies have the promise of creating parts with complex layered structures not possible with conventional manufacturing approaches, including parts using different metals layered in the same part and in complex shapes.

“We are making parts that carry structural load and have shielding built-in, typically several inches thick,” Norfolk explains. Cost and weight savings come from the combination of functions into one part.

Norfolk explains, “ASTM has a specification for additive manufacturing (AM) that recognizes different methods, including sheet lamination. We use a solid-state process to build layer by layer – some of the parts are made of thousands of layers of foil – typically 0.005" to 0.010" thick.” Norfolk adds that metal foils are less expensive than powders and available from multiple sources.

The company also 3D prints high-performance, lightweight heat exchangers by combining aluminum and copper in designs that would be hard to make with traditional manufacturing. “We can print coolant loops into the structure of a satellite so the frame can become a huge heat-exchanger,” Norfolk says.

Fabrisonic LLC