Views:36 Author:Site Editor Publish Time: 2019-09-24 Origin:Site
When ultrasonic acts on the thermoplastic plastic interface, it produces tens of thousands of high-frequency vibration per second. This kind of high-frequency vibration reaches a certain amplitude. The ultrasonic energy is transmitted to the welding area through the upper welding parts. Because the acoustic resistance of the welding area, i.e. the interface between two welding parts, is high, local high temperature will be generated.
Because of the poor thermal conductivity of the plastic, it can not be distributed in time and gathered in the welding area, resulting in the rapid melting of the contact surface of the two plastics, together with a certain pressure, to make them merge into one.
When the ultrasonic stops working, let the pressure continue for a few seconds to solidify and form a solid molecular chain, so as to achieve the purpose of welding, the welding strength can be close to the strength of raw materials.
The quality of ultrasonic plastic welding depends on the amplitude of the transducer welding joint, the pressure applied and the welding time. The welding time and the welding pressure can be adjusted, and the amplitude is determined by the transducer and the horn.
There is a suitable value for the interaction of these three quantities. When the energy exceeds the optimum value, the melting quantity of plastics will be large and the welding material will be easily deformed. If the energy is small, it will not be easy to solder firmly and the pressure imposed can not be too large. This optimum pressure is the product of the edge length of the welded part and the optimum pressure per mm of the edge.
The principle of ultrasonic metal welding is a special method to connect the same or different metals by using mechanical vibration energy of ultrasonic frequency (more than 15KHz).
When metal is welded by ultrasonic wave, it neither conveys electric current to the workpiece nor applies high temperature heat source to the workpiece, but transforms the vibration energy of wire frame into friction work, deformation energy and limited temperature rise between workpieces under static pressure.
Metallurgical bonding between joints is a kind of solid-state welding without melting of base metal. Therefore, it effectively overcomes the spatter and oxidation phenomena during resistance welding.
Ultrasonic metal welding machine can weld thin wires or thin sheets of non-ferrous metals such as copper, silver, aluminum and nickel by single spot welding, multi-spot welding and short strip welding.
It can be widely used in welding of thyristor lead, fuse, electrical lead, lithium battery electrode and ear.