Researchers have come up with an innovative 3D printing technique that utilizes acoustic holograms, known as holographic direct sound printing (HDSP). This new method enhances a technique introduced in 2022, which explained how sonochemical reactions occurring in microscopic cavitation areas—tiny bubbles—produce extremely high temperatures and pressures for incredibly brief moments, solidifying resin into intricate designs. By incorporating acoustic holograms that display cross-sectional views of a design, this method speeds up the process of polymerization, enabling the creation of objects all at once rather than building them one voxel at a time.
Researchers at Concordia have introduced an innovative 3D printing technique that utilizes acoustic holograms, promising faster production and the ability to fabricate more intricate objects.
The technique, called holographic direct sound printing (HDSP), is outlined in a recent publication in the journal Nature Communications. It improves on a previously described method from 2022, which highlighted how sonochemical reactions within tiny bubble formations generate extremely high temperatures and pressures for billionths of a second, allowing the resin to solidify into complex shapes.
By using acoustic holograms that hold cross-sectional representations of specific designs, the process of polymerization can occur at an accelerated rate, allowing for simultaneous production of multiple objects instead of progressing voxel by voxel.
To maintain the accuracy of the desired image, the hologram stays in a fixed position within the printing medium. The printing platform is connected to a robotic arm, which navigates it according to a pre-configured algorithm aimed at creating the final object.
Muthukumaran Packirisamy, a professor in the Department of Mechanical, Industrial and Aerospace Engineering, spearheaded the initiative. He suggests that this could enhance printing speeds by as much as 20 times while using less energy.
“We can even modify the image while the operation is ongoing,” he explains. “We have the ability to reshape designs, integrate multiple movements, and change the materials used in printing. By optimizing the parameters, we can create intricate structures by controlling the feed rate.”
A significant technological advancement
The researchers indicate that the accurate manipulation of acoustic holograms facilitates the storage of various images in one hologram. This capability allows for the concurrent printing of multiple objects at different spots within the same workspace.
As a result, acoustic holography is set to drive innovation across various fields, from creating complex tissue structures to developing targeted drug and cell delivery systems, as well as advancing tissue engineering. Practical applications include new types of skin grafts that can accelerate healing and improved methods for delivering therapeutics precisely where they are needed.
Moreover, since sound waves can penetrate opaque surfaces, HSDP can be employed to print inside the human body or behind solid objects. This characteristic could be beneficial for repairing damaged organs or intricate components located deep within an airplane.
The researchers believe that HDSP has the potential to revolutionize the field. Packirisamy compares it to the significant advancements seen in light-based 3D printing, transitioning from stereolithography—which uses a laser to cure resin one point at a time—to digital light processing, which allows for curing entire layers of resin simultaneously.
“The possibilities are endless,” he says. “We can print behind barriers, inside tubes, or even within the body. The methods and devices we presently utilize already have approval for medical uses.”
