(1) Principles and features:
Ultrasonic metal welding machine is a process in which metal weldments are connected in a solid state by the action of ultrasonic vibration. Mainly by ultrasonic generator, transducer vibration system, pressurizing device, time-controlled ultrasonic frequency power and electro-acoustic energy conversion, and input this energy into the weld zone; pressurizing device provides the pressure required for welding; time control device includes Automatic control of preload, weld, hold, depressurization and interval time.
(2) The mechanism of ultrasonic metal welding is complicated. So far, the mechanism of action is not very clear. It is similar to friction
However, there is a difference; the ultrasonic welding time is very short (about 1 s), and the temperature is lower than the recrystallization temperature; it is different from the pressure enthalpy because the applied static pressure is much smaller than the pressure welding. At present, the commonly accepted explanation is that the ultrasonic transducer vibration system generates longitudinal vibration, and the displacement amplitude is amplified and transmitted to the welding tool head to drive the upper weldment to vibrate. This vibration creates a friction-like effect at the interface of the two jaws. This friction can break the oxide film on the metal surface in the initial stage of the ultrasonic welding process, and cause repeated micro-welding and destruction of the convex portion of the rough surface. This process is repeated to make the contact area increase close to the atomic attraction. When the distance of action occurs, a metal bond is formed between them to form a solder joint. The characteristic of forming 悍 ultrasonic metal welding is that it does not need to input current to the workpiece, nor does it need to introduce a high-temperature heat source to the workpiece, and does not require flux, but converts the vibration energy into friction energy and deformation energy between the workpieces under static pressure. And limited temperature rise, so several flats have no thermal deformation, no residual stress; the pre-weld treatment of the weldment surface is not high; easy to achieve the destruction of dissimilar metals.
It should be noted that if the welding time is too long, or the ultrasonic vibration amplitude is too large, the welding strength will be reduced or even destroyed.