What is Ultrasonic Welding
What is Ultrasonic Welding?
Ultrasonic Welding (USW) is a welding technique that uses ultrasonic vibration of high frequency to weld the two pieces together. It is most commonly used to weld thermoplastic materials and dissimilar materials. Metal with a thin section can also be welded with USW.
Working Principle
A high frequency (20 kHz to 40 kHz) ultrasonic vibration is used to join two plastic pieces together. The high-frequency vibration generates heat energy at the interface of the two pieces and melts the material. The melted material fused with each other to form a strong weld on cooling and solidification.
The typical frequency used is 15, 20, 30, 35 or 40 kHz.
Main Parts
The various main parts or components of ultrasonic welding are ultrasonic welding
A Press: It is used to apply pressure on the two plastic pieces to be joined. It may be of pneumatic or electric driven type.
Nest or anvil or fixture: It is a clamping device that is used to hold and clamp the two plastic pieces together. It allows the high-frequency vibration directed to the interface of the two pieces.
An Ultrasonic Stack: It consists of the three components, a converter or piezoelectric transducer, a booster and a horn or sonotrode. These three elements are tuned to work on resonate frequency of 15 kHz, 20 kHz, 30 kHz, 35 kHz or 40 kHz.
Converter: It converts the electrical signals into high-frequency mechanical vibration. And it does so through the piezoelectric effect.
Booster: It modifies the amplitude of vibration mechanically. In some standard systems, it is used to clamp the stack in the press.
Horn or Sonotrode: It vibrates at high frequency and transmits the mechanical vibration to the two pieces to be welded. It also modifies the amplitude mechanically. It takes the shape of the part. The horn is made of titanium or aluminum.
An Ultrasonic Generator: It generates and delivers high-frequency electrical signals matching the resonance frequency of the stack.
Controller: It is used to control the movement of the press and delivery of the ultrasonic energy.
