All kinds of thermoplastic materials can be welded using ultrasonics; hard, amorphous plastics such as PC, PS, SAN, ABS and PMMA are best suitable. They provide very favorable transmission characteristics for ultrasonic energy and can thus be easily and properly welded, even with large dimensions. Semi-crystalline plastics like PA, PP, PE, and POM generally melt faster. Therefore, they are ideally weldable in the immediate near field of the sonotrode (weld tool).
In addition to plastics, nonferrous metals, such as copper, brass, nickel and aluminum can also be welded. Various metals can be safely and strongly joined using ultrasonics.
Ultrasonic welding is a fast and economical, but also complex technology. To evaluate a welding task you need experts. In the lab, our engineers test the feasability of the application: Is the material weldable? Is the component design adequate? Is there a proper energy director, that will focus the ultrasonic waves to define the melt initiation?
Ultrasonic engineering includes all services to ensure that the weld process is working properly and can be implemented trouble-free in your production. This begins with the determination of the process parameters and goes beyond the construction of the weld tools and equipment to complete integration solutions into existing machines/production lines.
The ultrasonic generator converts the supply voltage (50 Hz and 230V) into a high frequency voltage of 20, 30, or 35 kHz which is converted into mechanical vibrations in the converter. The wave increases itself on its way from converter through the booster to the sonotrode. The sonotrode is the actual weld tool, transferring the vibrations into the component.
The amplitude is the movement of the weld tool, and more specifically, the deflection at which the stack expands and contracts – between 5 and 50 µm. As comparison: The diameter of a human hair is only 100 µm. The frequency is the number of oscillations per second. With ultrasonic welding, frequencies between 20 and 35 kHz are used. 35 kHz equal 35.000 movements per second.
No, ultrasonic frequencies between 20 and 35 kHz are not harmful to humans. Sometimes unpleasant whistling side noises will occur. Therefore machines in the lower frequency range often have sound insulation.