The other day we were on a conference call with a potential client.  Well-schooled in ‘traditional’ 3D printing of metals, the client asked “Tell me about how you control the melt pool.”  This is a common misunderstanding about our process.   The fundamental distinguishing characteristic of UAM, in comparison to other metallic additive manufacturing technologies, is that it is a solid-state welding process – meaning that melting of metals does not occur – with all of the attendant impact of high temperatures on material properties.  If we are not melting, then how do we create a bond?

Without interference of the oxides that coat them, metals naturally want to bond to each other.  Our ultrasonic process uses a scrubbing action to break off the layer of oxide that lies on every metal surface in our atmosphere.  With a little bit of pressure and a little bit of heat, the metals form a solid state joining.  Below is a great video showing from Rice University two small metal wires in a vacuum.  As they are brought together you can watch then ‘snap’ together in a solid state bond.

By using ultasonics to weld thin layers of foil layer upon layer, we are able to 3D print solid metal parts with full density.  Ultrasound does create a small amount of heat, but in aluminum alloys we see peak temperatures under 250°F which is well below the melting temperature of any metal.

The low temperature bond enables unique UAM capabilities:

  • Welding dissimilar metals (no intermetallics)
  • Embedding sensors and electronics in solid metal parts (without damaging)
  • Welds that do not change underlying metal microstructure

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