Hertz (Hz) is the unit of measurement used to describe the frequency of the ultrasonic vibration used in ultrasonic welding. In ultrasonic welding, a high-frequency mechanical vibration is generated by an ultrasonic transducer and transmitted through a horn or sonotrode to the parts being welded. The frequency of the ultrasonic vibration is typically in the range of 15 kHz to 70 kHz, with 20 kHz and 40 kHz being the most commonly used frequencies.

The frequency of the ultrasonic vibration is an important factor in ultrasonic welding, as it affects the energy transfer to the parts being welded and can impact the strength and quality of the weld. Higher frequencies generally result in lower energy transfer but can provide finer control and more precise welding in thin materials. Lower frequencies provide more energy transfer and are better suited for welding thicker materials and larger parts.

The choice of frequency for an ultrasonic welding application will depend on several factors, including the thickness and type of material being welded, the desired strength and quality of the weld, and the size and shape of the parts being welded. It is important to carefully select the appropriate frequency for each specific application to ensure a successful and efficient welding process.