Ultrasonic welding has applications in many fields including the thermoplastics industry. So how does it work?

Ultrasound is a mechanical vibration similar to that produced by musical instruments. These vibrations are called ultrasound because they are at a frequency above than the hearing capacity of the human ear (greater than 16 kHz).

In an acoustic assembly, these pressure waves are produced by a generator. This sends an alternating current of the same frequency as the converter (or transducer).

Then the converter, which is made of piezoelectric ceramics, transforms this energy into mechanical vibrations.

The mechanical vibrations then generate heat friction exciting the plastic molecules, which begin to move. The plastic softens and melts allowing the components to bond. The welding action is done by the sonotrode.

Plastic ultrasonic welding technology is very suitable for plastic hot riveting or heat stacking.

ACOUSTIC ASSEMBLY FOR ULTRASONIC PLASTIC WELDING

The generator converts the mains network (50/60 Hz) electrical frequency into a corresponding high frequency electrical energy, in this diagram, to 20,000 Hz.

Then, the piezoelectric converter (or transducer) transforms the electrical 20,000 Hz into mechanical vibrations of the same frequency. The energy is then mechanical.

The booster, or amplitude amplifier, is used to increase or reduce the amplitudeproduced by the converter.

Finally, the last element of the acoustic chain, the sonotrode transmits ultrasound energy to the welding workpiece.

Much more than a simple hardware manufacturer, ALTRASONIC provides a set of ultrasonic plastic assembly solutions: spot welding, continuous welding, hot riveting, riveting, flanging, insertion and more.