The most common 3D printing technologies are laying layers of molten plastic, melting metal powder with the light of a powerful industrial laser, or using an ultraviolet laser beam that causes the liquid polymer to polymerize and strengthen. And recently, researchers at Canada’s Concordia University demonstrated a new approach to 3D printing that uses sound waves. And this new approach is called “Direct Audio Printing (DSP)”.

DSP 3D printing technology uses narrowly directed ultrasonic pulses focused in a container filled with PDMS polymer (polydimethylsiloxane, polydimethylsiloxane). At the maximum focusing point of the ultrasonic beam, there is a field that oscillates at ultrasonic speed. This leads to the formation of microscopic bubbles there.

The high velocity of the bubbles causes their temperature to rise to 15,000 Kelvin (14,727 degrees Celsius) and the pressure inside them to reach 1,000 bar. This increase in temperature and pressure takes a few picoseconds (trillions of seconds), but this is enough to polymerize the material at the point of the bubble.

By moving the ultrasonic emitter and adjusting the focusing range of the beam, you can create a three-dimensional object of any shape and complexity in the container. In addition, DSP technology allows you to print objects directly inside other objects without any harmful effects on the objects.

For example, with the help of DSP technology, you can repair any mechanism without opening the hull, which can be very useful for the repair and service of satellites directly in space. Alternatively, this technology allows you to print the implant directly onto the patient’s body, where the polymer was previously injected, in a way that does not threaten the human body.

In addition to the PDMS polymer, Canadian researchers have already tested DSP technology for making objects from ceramic material. Next are experiments with pure metals and metal-polymer composites. Source