The sonotrode is a piece of metal or tool that is exposed to ultrasonic vibration, and then gives this vibratory energy in an element to apply (gas, liquid, solid or tissue).
Following a standard frequency range of ultrasonic use (from 20 kHz to 70 kHz), the sonotrode resonates in frequency as "contraction" and "expansion" x times per second (x is the frequency). The amplitude is about 13 to 130 micrometres.
This resonance of acoustics wave of a half-wavelength, follows the characteristics of modulus elasticity of the material E (Young's modulus), its density ρ, the speed of sound through this material c, and the frequency f.
The shape of the sonotrode (round, square, with teeth, profiled ...), depends on the quantity of vibratory energy and a physical constraint for a specific application.
Its geometry must be optimized following the shape of the application.
They are made of titanium, aluminum or steel, with or without heat treatment (carbide)
Sonotrodes of small diameter are sometimes called probes.
For an ultrasonic welding or cutting application, the sonotrode gives energy directly to the welding contact area, with little diffraction. This is particularly helpful when vibrations (wave propagation) could damage surrounding electronic components.[1]