Any company's ultrasonic welding machine has a center frequency, such as 20Khz, 40khz, etc. The working frequency of the welding machine is mainly determined by the mechanical resonance frequency of the transducer, the horn, and the welding head. The frequency of the generator is based on the mechanical resonance. The frequency is adjusted to achieve consistency, so that the horn operates in a resonant state, and each part is designed as a half-wavelength resonator. Both the generator and the mechanical resonance frequency have a resonant operating range, such as a general setting of ±0.5Khz, in which the welding machine can basically work normally. When we make each welding head, we will adjust the resonant frequency. It is required that the resonant frequency and design frequency error is less than 0.1khz. For example, the 20khz welding head, the frequency of our welding head will be controlled at 19.9-20.1khz, and the error is less than 5%.