Frequency in ultrasonic welding refers to the number of sound waves that are generated per second by the ultrasonic welding equipment. It is typically measured in hertz (Hz), and ultrasonic welding typically uses frequencies in the range of 15 kHz to 70 kHz.

The frequency of the sound waves produced during ultrasonic welding is a critical parameter that can affect the quality and strength of the weld. Higher frequencies generally produce smaller and more localized vibrations, which can be useful for welding smaller parts or materials that are more delicate or brittle. Lower frequencies generally produce larger and more widespread vibrations, which can be useful for welding larger parts or materials that require more energy to bond.

The specific frequency used in ultrasonic welding depends on a variety of factors, including the materials being welded, the size and shape of the parts, and the desired strength and quality of the weld. In general, higher frequencies are used for thinner and more delicate materials, while lower frequencies are used for thicker and more robust materials. The frequency can be adjusted or tuned using various parameters, such as the horn design, the amplitude of the vibrations, and the power of the ultrasonic welding equipment.