Negative pressure ocurs between the soldering base material and solder material according to the cavitation effect generated from high-frequency ultrasonic vibrations ( a few microns amplitude of cavitation ) of the ultrasonic wave. As a result, application of an ultrasonic wave will promote removal of the dirt of the base material surface, reduction of an oxide film, metal diffusion, removal of air bubbles, etc.
As a concrete expectation effect, it leads to improvement in wettability and spreadability of the solder by activation of a soldering object, stability of through-hole solder penetration on multilayer board, reduction of soldering time, etc...
Applications of ultrasonic soldering
- Soldering to glass (Special solder materials for glass are used)
Comparison of solder spreading by soldering on the surface-oxidized copper plate.
Wettability and spreading effects of flux are increased by applying an ultrasonic wave.
1- Iron tip
2- Heater element
3- Connecting horn
4- Ultrasonic transducter
It solders vibrating the soldering iron tip at a few microns amplitude by adding an ultrasonic wave to the conventional soldering iron. Since the structure of heater and iron tip is the same composition as the existing Japan Unix soldering robot corresponding to lead-free soldering, stable ultrasonic wave and temperature can be maintained also in soldering automation.