Ultrasonic welding uses high-frequency vibration waves to transmit to the surfaces of two objects to be welded. Under pressure, the surfaces of the two objects rub against each other to form fusion between the molecular layers.
Ultrasonic welding uses an ultrasonic generator to convert 50/60 Hz current into 15, 20, 30 or 40 KHz electrical energy. The converted high-frequency electrical energy is converted again into mechanical motion of the same frequency through the transducer, and then the mechanical motion is transmitted to the welding head through a set of horn devices that can change the amplitude. The welding head transmits the received vibration energy to the joint of the workpiece to be welded. In this area, the vibration energy is converted into heat energy through friction, melting the plastic. Ultrasound can be used not only to weld hard thermoplastics, but also to process fabrics and films.
The main components of an ultrasonic welding system include ultrasonic generator, transducer/horn/welding head trio, mold and frame.
Linear vibration friction welding uses frictional heat energy generated at the contact surface of two workpieces to be welded to melt the plastic. Thermal energy comes from the reciprocating movement of a workpiece on another surface with a certain displacement or amplitude under a certain pressure. Once the desired degree of welding is reached, the vibration will stop, while a certain amount of pressure will still be exerted on the two workpieces, allowing the newly welded parts to cool and solidify, thereby forming a tight bond.
Orbital vibration friction welding is a welding method that utilizes frictional heat energy. During orbital vibration friction welding, the upper workpiece performs an orbital motion - a circular motion in all directions - at a fixed speed. Movement can generate heat energy, causing the welded portion of the two plastic parts to reach the melting point. Once the plastic begins to melt, the movement stops and the welded portions of the two workpieces solidify and join firmly together. Small clamping forces will result in minimal deformation of the workpiece, and workpieces up to 10 inches in diameter can be welded using orbital vibration friction.
Ultrasonic plastic welding principle
When ultrasonic waves act on the contact surface of thermoplastic plastics, they will produce tens of thousands of high-frequency vibrations per second. This high-frequency vibration reaching a certain amplitude transmits ultrasonic energy to the welding area through the upper weldment. Since the welding area is two The sound resistance at the welding interface is large, so local high temperatures will occur. And due to the poor thermal conductivity of plastic, it cannot be dissipated in time and gathers in the welding area, causing the contact surface of the two plastics to melt rapidly. After a certain pressure is applied, they fuse into one. When the ultrasonic waves stop acting, let the pressure continue for a few seconds to solidify and form, thus forming a strong molecular chain to achieve the purpose of welding, and the welding strength can be close to the strength of the raw material. The quality of ultrasonic plastic welding depends on three factors: the amplitude of the transducer welding head, the applied pressure and the welding time. The welding time and welding head pressure can be adjusted, and the amplitude is determined by the transducer and horn. There is an appropriate value for the interaction of these three quantities. When the energy exceeds the appropriate value, the melting amount of the plastic will be large and the welded object will be easily deformed; if the energy is small, it will not be easy to weld firmly, and the pressure applied cannot be too large. This optimal pressure is the product of the side length of the welded part and the optimal pressure per 1mm of the edge.
Ultrasonic metal welding principle
The principle of ultrasonic metal welding is a special method that uses mechanical vibration energy at ultrasonic frequency to join similar metals or dissimilar metals. When metal is undergoing ultrasonic welding, it does not deliver current to the workpiece, nor does it apply a high-temperature heat source to the workpiece. It only converts the vibration energy of the wire frame into friction work, deformation energy and limited temperature rise between the workpieces under static pressure. ． The metallurgical bond between joints is a solid-state welding that is achieved without melting the base metal. Therefore, it effectively overcomes the phenomena of spatter and oxidation produced during resistance welding. Ultrasonic metal welding machine can perform single-point welding, multi-point welding and short strip welding on filaments or sheet materials of non-ferrous metals such as copper, silver, aluminum and nickel. It can be widely used in the welding of thyristor leads, fuse pieces, electrical appliance leads, lithium battery pole pieces, and tabs.
Advantage
- Advantages of ultrasonic plastic welding: fast welding speed, high welding strength and good sealing;
Replacing the traditional welding/bonding process, it is low cost, clean and pollution-free and will not damage the workpiece;
The welding process is stable, and all welding parameters can be tracked and monitored through the software system. Once a fault is discovered, it is easy to troubleshoot and maintain.
- Advantages of ultrasonic metal welding: 1) The welding material does not melt and has no fragile metal properties. 2) After welding, the conductivity is good and the resistance coefficient is extremely low or almost zero. 3) The requirements for the surface of the welding metal are low, and both oxidation and electroplating can be welded. 4) The welding time is short and no flux, gas or solder is required. 5) Welding without sparks, environmentally friendly and safe.
Applicable Products
1), Ni-MH battery Ni-MH battery nickel mesh and nickel sheets melt with each other and nickel sheets melt with each other. 2) For lithium batteries and polymer batteries, copper foil and nickel sheets melt with each other, and aluminum foil and aluminum sheets melt with each other. 3) The wires fuse with each other and form one or more wires that fuse with each other. 4) The wires and various electronic components, contacts, and connectors are fused together. 5) Mutual fusion of large heat sinks, heat exchange fins, and honeycomb cores for various home appliances and automotive supplies. 6), high current contacts such as electromagnetic switches and fuseless switches, and mutual fusion of dissimilar metal sheets. 7), sealing and cutting of metal pipes to make them waterproof and airtight.
Application Prospects
For all application markets, ultrasonic welding has won recognition from all walks of life for its unique advantages - fast, efficient, clean and strong.
- Automobile: (Transportation industry) Ultrasonic waves can be controlled by computer programs to weld large and irregular workpieces such as bumpers, front and rear doors, lamps, brake lights, etc. With the development of high-grade roads, ultrasonic welding is increasingly used for reflectors.
- Home appliances: With appropriate adjustments, it can be used for: portable fluorescent lamp shades, steam ironing doors, TV casings, cassette recorders, audio player transparent panels, power rectifiers, TV casing screw holders, mosquito-reducing lamp casings, washing machine dehydration sinks, etc. Sealed, strong and beautiful home appliances.
- Packaging: Sealing of hoses and connection of special packing tapes.
- Toy industry: Due to the use of ultrasonic technology, the products are clean, efficient and strong, eliminating the need for screws, adhesives, glue or other auxiliary products, reducing production costs and greatly enhancing the competitiveness of enterprises in the market.
- Electronics: Use automated solution design to enable users to achieve large-scale production while ensuring product quality requirements.
- Other commercial uses: From communication equipment, computer industry, printing equipment to audio and video products, etc., ultrasonic equipment can be used.
Post time: 2023-10-09 15:09:11