C. Birkland, A. Swanson, and T. Matula
University of Washington Applied Physics Lab, Washington, United States
Keywords: Manufacturing, Bonding, Epoxy, Adhesives, Sealants
High Intensity Focused Ultrasound (HIFU) presents a novel focused-ultrasound heating mechanism for use in manufacturing, more specifically bonding of materials. With HIFU, a hotspot only occurs at the focus, analogous to a magnifying glass, where a targeted beam of acoustic energy is able to pass through opaque materials without damaging them. This enables targeted, high-efficiency bonding of assemblies and within the interiors of parts where lasers and UV are not applicable. The targeted heating is effective in controlled welding of thermoplastics, curing of epoxies (including those used in composites), and a variety of other adhesives and sealants. Target site heating up to 300 C has been observed in seconds. HIFU-curing is different than ultrasonic welding, which requires direct contact to vibrate the pieces to partially melt the contact point and weld them together. HIFU is a unique focused-ultrasound directed-energy source that bonds materials “at a distance,” without having to subject the entire part to heat or vibration. Energy deposition is immediate and controllable. The transducer can be an array, allowing for electronic steering of the focus, or alternatively, a single element that can be mechanically moved by traditional CNC positioning systems, integration with robotics, or many other application specific arrangements.