Ultrasonic cognition——The physical definition of ultrasonic wave is: the transmission of vibration in an object forms a wave. The formation of such waves must have two conditions: one is the vibration source, and the other is the propagation medium. Generally, waves are classified according to vibration direction and propagation direction. When the vibration direction is perpendicular to the propagation direction, it is called shear wave. When the vibration direction is consistent with the propagation direction, it is called longitudinal wave. Wave propagation in objects mainly has the following parameters: velocity V, frequency F, and wavelength input. Relationship between the three: V=F Enter. The speed of wave propagation in the same material is certain, so different frequencies lead to different wavelengths. In addition, it is also necessary to consider that there is always attenuation of wave propagation in objects. The farther the propagation distance is, the more energy attenuation will be. This is also considered in ultrasonic processing.

Principles of ultrasonic metal welding——High frequency amplitude of ultrasonic wave can generate enough energy under pressure to destroy the welding position. The stress and strain of this vibration will realize metallurgical bonding conditions between metal molecules, so as to change the molecular structure, local surface displacement and plasticity of two metal surfaces. Phase transformation occurs between welding areas, recrystallization, diffusion and metal rearrangement occur, involving infiltration and mixing into a whole, so as to achieve fusion effect and form welding.

Application principle of ultrasonic plastic welding——The application principle of ultrasonic wave in plastic processing: the principle is to use the peak position of longitudinal wave to transfer the amplitude to the gap of plastic parts. Under pressure, the molecules of two plastic parts or other parts and the contact part of plastic parts rub against each other to produce melting, so that the plastic at the contact position can be fused to achieve the purpose of processing and welding.