With the rapid development of the material industry, which is light weight, small friction, corrosion resistance, easy processing of plastic and its metal composite materials by the people's attention. Plastic products, has penetrated into the daily life of various fields, but also widely used in aviation, shipbuilding, automotive, electrical, packaging, toys, electronics, textiles and other industries. However, due to the injection molding process and other factors, in a considerable part of the shape of complex plastic products can not be a single injection molding, which requires bonding, and the use of plastic bonding and heat treatment process for many years is quite backward, not only low efficiency, Agents also have a certain poison *, causing environmental pollution and labor protection and other issues. The traditional process of this technology can not be applied to the development of modern plastics industry needs, so a new plastic processing technology - ultrasonic plastic welding with its efficient, high quality, beautiful, energy saving and other advantages * stand out. Ultrasonic plastic welding machine in the welding of plastic products, that is, do not fill any adhesive, filler or solvent, do not consume a lot of heat, with easy operation, welding speed, high welding strength, high production efficiency. As a result, ultrasonic welding technology is increasingly widely used.
First, the working principle of ultrasonic plastic welding machine
When the ultrasonic effect on the thermoplastic * plastic contact surface, will produce tens of thousands of times per second high-frequency vibration, which reaches a certain amplitude of high-frequency vibration, through the welding pieces of ultrasonic energy to the welding area, That is, the intersection of two welding at the interface of large resistance, it will produce local high temperature. And because the plastic heat * poor, and sometimes can not be distributed in time, gathered in the welding area, resulting in two plastic contact surface rapid melting, coupled with a certain pressure, to integrate into one. When the ultrasonic stops, let the pressure last for a few seconds to make it solidified, thus forming a solid molecular chain, to achieve the purpose of welding, welding strength can be close to the strength of raw materials. Ultrasonic plastic welding depends on the quality of the transducer welding head amplitude, pressure and welding time and other three factors, welding time and welding head pressure can be adjusted, the amplitude determined by the transducer and horn. These three quantities have a suitable value with each other, the energy exceeds the appropriate value, the amount of plastic melting on the large, easy to weld deformation; if the energy is small, it is not easy to solder, the pressure can not be increased. This optimum pressure is the product of the length of the welded portion and the edge of the optimum pressure per 1mm.
Second, the ultrasonic plastic welding method
1, welding ultrasonic vibration with the welding head will be ultrasonic conduction to the weld, due to the two welding parts at the large resistance, resulting in local high temperature, so that welding interface melting. Under a certain pressure, so that the two welding pieces to achieve beautiful, fast, strong welding effect.
2, buried nuts or other metal to be inserted into plastic parts. First, the ultrasonic transmission to the metal, the high-speed vibration, so that the metal directly embedded in the molding of plastic, while the plastic melting, the completion of the completion of the buried.
3, riveting method to metal and plastic or two different quality of plastic joint, can use the ultrasonic riveting method, so that welding is not easy to brittle, beautiful, strong.
4, spot welding using a small welding head will be two large plastic products sub-point welding, or the entire row of tooth-like welding head directly on the two pieces of plastic parts, so as to achieve the effect of spot welding.
5, forming the use of ultrasonic plastic parts instantly melt molding, when the plastic solidification can make metal or other materials, plastic solid.
6, the removal of the use of welding head and the base of the special design, when the plastic workpiece just shot, the pressure directly on the plastic branches, through the ultrasonic conduction to achieve the effect of excision.
Third, the composition of the sound wave welding machine and its role
Ultrasonic plastic welding machine by the pneumatic transmission system, control system, ultrasonic generator, transducer and tool head and mechanical devices and other components.
1, pneumatic transmission system
Including: over the device, pressure reducing valve, oil mist, commutator, throttle, cylinder and so on.
Work first by the air compressor drive stroke cylinder to drive the ultrasonic transducer vibration system up and down movement, dynamic pressure in the small and medium power ultrasonic welding pressure according to the need to set the welding.
2, the control system
The control system consists of a time relay or an integrated circuit time timer. The main function is: First, control the work of the pneumatic transmission system, so that when the welding under the control of time to open the gas valve, the cylinder pressure to reduce the welding head to a certain pressure to suppress the welding objects, when the welding pressure after a period of time , And then control the system to change the gas valve, so that the welding head to return to reset; the second is to control the ultrasonic generator working time, the system so that the entire welding process to achieve automation, the operation only start button to generate a trigger pulse, will be able to automatically In the whole process of welding. The order of the entire control system is: the power to start a trigger control signal Pneumatic drive system, cylinder pressure welding head down and press the trigger to trigger the ultrasonic generator work, launch ultrasound and maintain a certain welding time to remove the ultrasonic emission continue to maintain a certain pressure time back pressure The welding head picks up the welding end.
3, ultrasonic generator
1) the power of the ultrasonic plastic welding machine, the generator signal using phase-locked frequency automatic tracking circuit, so that the generator output frequency is basically consistent with the transducer resonant frequency.
2) power of 500W or more ultrasonic plastic welding machine used by the self-excited power oscillator, also has a certain frequency tracking capability.
4, ultrasonic plastic welding machine used in the acoustic system
Ultrasonic plastic welding machine with the acoustic system consists of three parts: 1 drive part 2 fixed part 3 working part. In the above three components, the drive is the core, generally using a bolt-clamped longitudinal vibration transducer, where the half-wavelength longitudinal vibrator and the quarter-wavelength longitudinal vibrator, half-wavelength longitudinal vibrations and half-wavelength concentrator phase Connected to form a full-wavelength plastic welding transducer, and a quarter-wavelength longitudinal transducer connected to a quarter-wavelength concentrator to form a half-wavelength transducer.
2) Tool head
For different welding objects need to have different tool head, whether it is near-field welding or transmission welding, only half-wavelength tool head to make the welding end to achieve the maximum amplitude.
Tool head, with amplitude amplification and no amplitude amplification of the two, plastic welding machine with acoustic system tool head, the material used is usually aluminum alloy, the end of the plated carbide, power is also useful when the titanium alloy material Into the material, the fatigue strength is more than twice as high as aluminum.
Fourth, the ultrasonic plastic welding machine models and specifications
Ultrasonic plastic welding machine due to the use of occasions and different welding materials, welding size is not the same size, its specifications are all kinds of. Its output power from the tens of watts of hand-welding machine to the mainframe several kilowatts frequency is generally 15KHz to 40KHz range. Wuxi Jimei developed 15KHz, 20KHz ultrasonic plastic welding machine is a relatively wide range of models, the output power of 1000W-4000W, respectively, the operating frequency of 15KHz, 20KHz, and light weight, good quality, is the plastics industry One of the preferred ultrasonic plastic welding machine manufacturers.
Ultrasonic plastic welding machine is its irreplaceable advantage, into the plastic industry, play a huge role in creating a huge benefit at the same time, but also look forward to the ultrasonic plastic welding function has a greater breakthrough for the plastics industry to play Greater contribution.