Direct sound printing is a potential game changer in 3D printing

New printing technology uses ultrasonic waves to create complex and precise objects.

Most 3D printing methods currently in use rely on either photo (light) or thermo (heat) activated reactions to achieve precise polymer manipulation. A third option may be offered by the development of a new platform technology called direct sound printing (DSP), which uses sound waves to produce new objects.

DSP relies on chemical reactions created by fluctuating pressure inside tiny bubbles suspended in a liquid polymer solution.

The reactions caused by the ultrasound-driven oscillation inside the microbubbles are intense, although they only last for picoseconds. The temperature inside the cavity rises to about 15,000 Kelvin and the pressure exceeds 1,000 bars (the pressure on the Earth's surface at sea level is about one bar). The reaction time is so short that the surrounding material is not affected.

The researchers experimented with a polymer used in additive manufacturing called polydimethylsiloxane (PDMS). They used a transducer to generate an ultrasonic field that passes through a shell of building material and solidifies the target liquid resin, depositing it on a platform or other previously solidified object. The converter moves along a predetermined path, or creates the desired product pixel by pixel. The parameters of the microstructure can be adjusted by adjusting the duration of the frequency of the ultrasonic waves and the viscosity of the material used.

The authors believe that the versatility of DSP will benefit industries that rely on highly specific and delicate devices. Polymeric PDMS, for example, is widely used in the microfluidic industry, where manufacturers require a controlled environment (clean rooms) and sophisticated lithography techniques to create medical devices and biosensors.

Aerospace engineering and repair can also benefit from DSP because ultrasonic waves penetrate opaque surfaces like metal shells. This can allow maintenance crews to service parts located deep in the fuselage that would be inaccessible to printing techniques dependent on photoactivated reactions. DSP could even have medical applications for remote body printing for humans and other animals.

Source: www.sciencedaily.com