Through the friction between the molecules of the object, the vibration energy generated by the ultrasonic wave is converted into heat energy, so that the welding surfaces of the object parts are fused together. This is the principle of the ultrasonic welding machine. Ultrasonic welding machines use the vibration frequency of ultrasonic waves to weld objects. There are many kinds of equipment for welding objects through ultrasonic waves, including pneumatic transmission systems, transducers and ultrasonic generators, control circuits and welding heads. The working process of the ultrasonic welding machine: First, the ultrasonic generator converts the high-voltage current into high-frequency electric energy, and then the converted high-frequency electric energy is converted into mechanical vibration of the same frequency through the transducer, and then the mechanical vibration passes through the action of the horn. It is amplified and transmitted to the welding head, and finally the welding head transfers the received vibration energy to the joint surface between the welding objects.
In the process of welding objects using ultrasonic waves, under the influence of the heat energy generated by the vibration energy of the welding interface, the ultrasonic welding wire is first melted, and then the welding wire is spread in the gap of the welding surface under the action of ultrasonic welding pressure, and then A layer of molten plastic is formed between the welding surfaces. Finally, after the molten plastic is completely cooled and solidified, the welding surfaces of the two object workpieces are combined. In a perfect welding work, all the melting of the ultrasonic welding wire just spreads in the gap of the entire welding surface, so the welding firmness obtained in this way is guaranteed, and the welding interface has aesthetics. However, when the welding amplitude is too large and the welding time is too long, the heat generated by the vibration energy will exceed the heat required to melt the welding wire, resulting in the melting of the workpiece material other than the ultrasonic welding wire. If the welding pressure is high, the workpiece material of the molten layer will be seriously squeezed out, resulting in weak welding.
During the welding process, there should be a pre-pressure on the welding surfaces of the two welding workpieces so as to improve the firmness of the welding. Welding pressure generates friction between two objects through vibrational energy, but the pressure generated by welding has a direct impact on the magnitude of the frictional force generated, which in turn has a certain impact on the rate of heat generation. The welding between the two workpieces is to melt the welding line through the pressure generated by the welding, so that it spreads in the gap of the welding surface, and the pressure generated by the welding must be maintained before the molten material cools and solidifies. Able to form beautiful welded joints.
The strength of the firmness of the welding is the criterion for judging the quality of the welding. Too much or too little melting of the welding wire material, too much or too little molten material spread on the welding surface, and too large or too small of the welding pre-pressure before the molten material cools and solidifies will affect the firmness of the welding, thereby reducing the welding performance. the quality of. To improve the strength of welding firmness, it is necessary to reasonably grasp the amount of melting of the welding wire material, the amount of molten material spread on the welding surface, and the size of the welding pre-pressure before the molten material cools and solidifies, so as to ensure the quality of welding and make the welding The interface is more beautiful.