As additive manufacturing (AM) becomes more widespread, new technologies are allowing for the use of AM to create a wider variety of parts and devices. For applications that require non-contact manufacturing, ultrasonic particle manipulation is presenting some new opportunities. Ultrasonic particle manipulation isn’t new, but in AM, it’s becoming a way to harness acoustic radiation forces to trap and move particles or small devices during the printing process.
Ultrasonic manipulation uses ultrasonic waves to create a wave field of varying pressure profiles that can trap and manipulate particles in a certain medium. (Essentially, items become trapped at regions of low acoustic pressure.) It’s a non-contact manipulation method that’s capable of handling particles or components with very different mechanical properties, shapes and sizes, and this presents interesting opportunities for additive manufacturing. Mechanical handling is difficult and complex for very small materials in the submillimeter size range, or for components that are sensitive to touch damage.
|Ultrasonic particle manipulation levitates material in a wave field. Image source: Neurotechnology.|
While there are other methods of non-contact manipulation such as magnetic or electrostatic processes, they’re suitable for only a narrow range of materials. Materials need to be magnetic for magnetic manipulation to work, and electrostatic particle manipulation can work only on particles that are influenced by electrostatic fields. (It can also damage electronic components.) With ultrasonic manipulation, a much wider range of materials can be handled: plastics, metals and even liquids, which offers greater versatility.
Vilnius, Lithuania-based Neurotechnology, originally founded as a biometric technology company, is developing a patent-pending process that will allow for the use of ultrasonic particle manipulation in additive manufacturing (AM).
While there are many 3D printing and assembly technologies, they are usually suited either for printing a certain material or assembling certain components, according to Dr. Osvaldas Putkis, research engineer and project lead for Neurotechnology’s Ultrasound Research Group. Ultrasonic manipulation could incorporate assembly into AM, widening the capabilities of current printers, potentially leading to the creation of a printer that could print and assemble whole devices.
“We think that the capability of ultrasonic manipulation to handle very different materials and components can improve existing 3D printing methods and incorporate component assembly into a single device,” Putkis told Design News . “After creating an Ultrasound Research Group at Neurotechnology three years ago and gaining initial theoretical knowledge and technological experience of ultrasonic manipulation, we decided to start research and development of 3D printing/assembly based on ultrasonic manipulation.”
The result is a prototype device that includes an array of ultrasonic transducers that emit ultrasonic waves. With the ability to control all the transducers individually, users can create specific pressure profiles that can trap and rotate particles or components of nearly any composition -- from solder to plastic components, foam and even liquids – to a high degree of precision. Objects ranging from a few millimeters to only tens of microns can be moved, depending on the frequencies used (the higher the frequency, the higher the accuracy). Beyond raw materials, the technology has proven useful for manipulating electronic components. Sensitive components