With the popularity of welding technology, ultrasonic wave has been invented as a new welding method, which has unparalleled advantages in the welding of the same or different metals. Because ultrasonic non-metallic welding does not require flux and external heat sources, the welded structure will not be deformed by heat and there will be no residual stress.
Introduction to Ultrasonic welding technology
Ultrasonic welding is the use of high frequency vibration wave transmitted to the surface of two objects to be welded, in the case of pressure, so that the two objects surface friction and the formation of fusion between molecular layers. The main components of a set of ultrasonic welding system include ultrasonic generator, ultrasonic transducer, ultrasonic flange, ultrasonic horn, mold and ultrasonic machine body.
Ultrasonic welding principle
Principle of ultrasonic plastic welding: ultrasonic action on the plastic contact surface of thermoplastic, will produce tens of thousands of times of high-frequency vibration per second, this reach a certain amplitude of high-frequency vibration, the ultrasonic energy is transmitted to the welding area, because the welding area is two welding interface at the sound resistance, so it will produce local high temperature.
And because of the poor thermal conductivity of plastic, it can not be distributed in time, gathered in the welding area, resulting in the rapid melting of the contact surface of the two plastics, and a certain pressure, so that it is fused into one. When the ultrasonic stops working, let the pressure continue for a few seconds to solidify, forming a solid chain of molecules that can be welded with a strength close to that of the raw material.
The quality of ultrasound plastic welding depends on the amplitude of the transducer welding head, the added pressure and welding time and other three factors, welding time and welding head pressure can be adjusted, the amplitude is determined by the transducer and the amplitude rod.
There is a suitable value for the interaction of these three quantities. When the energy exceeds the suitable value, the melting amount of plastic will be large and the welding material is easy to deform. If the energy is small, it is not easy to weld, the added pressure can not be too large. This optimum pressure is the product of the edge length of the welded part and the optimum pressure per 1mm of the edge.
Principle of ultrasonic metal welding: The principle of ultrasonic metal welding is a special method to connect the same or dissimilar metals by using the mechanical vibration energy of ultrasonic frequency (more than 16KHz). Metal in ultrasonic welding, neither the transmission of current to the workpiece, nor the workpiece is subjected to high temperature heat source, but under static pressure, the vibration energy of the frame into the friction work between the workpiece, deformation energy and limited temperature rise.
Metallurgical bonding between joints is a solid state welding without melting of the base metal. Therefore, it can effectively overcome the spatter and oxidation caused by resistance welding. Ultrasonic welding machine can be used for single point welding, multi point welding and short strip welding of copper, silver, aluminum, nickel and other non-ferrous metal filaments or thin sheet materials. It can be widely used in the welding of silicon controlled lead, fuse piece, electrical lead, lithium battery pole piece and pole ear.
Ultrasonic welding process
1) Welding method: with ultrasound high frequency vibration welding head under moderate pressure, make two pieces of plastic joint surface friction heat and instantaneous melting joint, the welding strength can be comparable to ontology, adopt the appropriate artifacts and reasonable interface design, can achieve watertight and airtight, and USES the AIDS the inconvenience of cancellation, efficient clean welding.
2) Shape: similar to maohan method, this method will be concave shape welding head pressure in the plastic outer ring, sonic welding hair surplus after ultra-high frequency vibration will melt forming and plastic coated in metal objects to be fixed, and is smooth and beautiful appearance, this method is used in electronics, the horn of a fixed shape, and cosmetics of lens fixed, etc.
3) Heat staking：with the transmission of the welding head and appropriate pressure, the metal parts (such as nuts, screws, etc.) are squeezed into the reserved plastic hole and fixed at a certain depth. After completion, the tension and torque can be comparable to the strength of the traditional mold forming, which can avoid the defects of injection mold damage and slow injection.
4) Riveting welding: riveting welding method refers to the vibration of the welding head to press the protrusion of the item so that the hot melting into rivet shape, so that the two objects mechanical riveting.
5) Spot welding: Spot welding refers to the point welding of the object that is not easy to design for the welding line, which can also achieve the welding effect.
Suitable material for ultrasonic welding
1. Ultrasonic welding is suitable for all thermoplastics, amorphous plastics such as ABS,PMMA,PC,PS; Semi-crystalline plastics such as PA,PET,CA,POM,PE and PP.
2. Ultrasonic welding is also suitable for non-textile fabrics, such as thermoplastic fabrics, polymeric materials, coated paper and mixed fabrics.
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Post time: Oct-27-2022