3D Ultrasound Printing | Science and Technology News (Amazings® / NCYT®)

Most 3D printing methods in use today rely on photocatalytic or thermoplastic reactions to achieve precise processing of the polymers used. The development of a new form of printing called “direct sonic printing” (DSP), which uses sound waves to produce new objects, may offer a new option.

Ultrasound frequencies are already used in destructive procedures such as resections of tissues and tumors. The team of Muthukumaran Packirisamy and Mohsen Habibi at Concordia University in Canada set out to use them to make things.

The new process relies on using focused ultrasound to create sonochemical reactions in tiny bubbles suspended in a liquid polymer solution. Extreme temperatures and pressures lasting a billionth of a second can generate complex, pre-designed geometries that cannot be achieved with conventional techniques.

The research and development team found that by using the right type of ultrasound at the right frequency and power, it is possible to create highly focused and chemically reactive regions at highly localized points. Essentially, bubbles can be used as high-efficiency reactors to drive chemical reactions that turn liquid resin into solid or semi-solid structures.

The feedback induced by the ultrasound-guided oscillation within the microbubbles is severe, although it only lasts for milliseconds. The temperature inside the cavity or bubble reaches about 15,000 °C and the pressure exceeds 1,000 bar (the Earth’s surface pressure at sea level is about 1 bar). The reaction time is so short that the surrounding material is not affected.

An artistic reformulation of the concept of 3D printing using ultrasound. (Illustration: Amazings/NCYT)

The Packirisamy team believes that the versatility of direct sonic printing will be of great benefit in industries such as microfluidics. The PDMS polymer, for example, is widely used in microfluidics. Manufacturers in this field need to operate in highly controlled environments (clean rooms) and use state-of-the-art lithography techniques to create critical medical devices and biosensors.

Aerospace maintenance and repair jobs can also benefit from direct acoustic printing, where ultrasound penetrates surfaces such as metal casings that are difficult to penetrate using other technologies. This could allow maintenance personnel to repair parts deep inside the fuselage that are inaccessible to printing technologies that rely on photo-activated interactions.

Direct voice printing could have medical applications for remote printing within the human body.

Bakirisame, Habibi and their colleagues reveal technical details of the new 3D printing method in the academic journal Nature Communications, titled “Direct sound printing.” (Line: NCYT by Amazings)