Ultrasonic Welding Technology
Ultrasonic welding (USW) is a welding technique that uses high frequency ultrasonic vibration to weld two parts together. It is most commonly used to weld thermoplastic materials and different materials. Thin section metals can also be welded with USW.
Working Principle
The two plastic parts are joined together using high frequency (20 kHz to 40 kHz) ultrasonic vibration. The high frequency vibration generates thermal energy at the interface of the two components and melts the material. The molten materials fuse with each other and form a strong weld when cooled and solidified.
Typical frequencies used are 15, 20, 30, 35 or 40 kHz.
A Press: Used to apply pressure to the two plastic parts to be joined. It can be pneumatic or electric driven.
Nesting or anvil or clamp: It is a clamping device used to secure and clamp two plastic parts together. It allows high frequency vibrations to point to the interface of the two components.
Ultrasonic stack: It consists of three parts, a converter or piezoelectric sensor, an enhancer and a horn or ultrasonic generator. These three components are tuned to operate at a resonant frequency of 15 kHz, 20 kHz, 30 kHz, 35 kHz or 40 kHz.
Converter: It converts electrical signals into high frequency mechanical vibrations. It is achieved by the piezoelectric effect.
Booster: It mechanically modifies the amplitude of the vibration. In some standard systems it is used to clamp the stack in the press.
Horn or ultrasonic generator: It vibrates at high frequencies and transmits mechanical vibrations to the two components to be welded. It also mechanically modifies the amplitude. It takes the shape of the part. The horn is made of titanium or aluminum.
Ultrasonic generator: It generates and provides a high frequency electrical signal that matches the resonant frequency of the stack.
Controller: Used to control the movement of the press and the delivery of ultrasonic energy.