What is ultrasonic plastic welding machine?
When welding plastic products, ultrasonic plastic welding machine neither adds any adhesive, filler or solvent, nor consumes a large amount of heat source. It has the advantages of simple operation, fast welding speed, high welding strength and high production efficiency. Therefore, ultrasonic welding technology is more and more widely used. When the ultrasonic wave acts on the thermoplastic plastic contact surface, it will produce tens of thousands of high-frequency vibrations per second. This high-frequency vibration with a certain amplitude will transmit the ultrasonic energy to the welding area through the upper weldment. Due to the large acoustic resistance at the interface between the two welding areas, local high temperature will be generated. In addition, due to 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. After a certain pressure is added, it is integrated into one. When the ultrasonic wave stops working, let the pressure last for a few seconds to solidify and form, so as to form a solid molecular chain to achieve the purpose of welding, and the welding strength can be close to the strength of raw materials. The quality of ultrasonic plastic welding depends on three factors: the amplitude of transducer welding head, the applied pressure and welding time. The welding time and welding head pressure can be adjusted, and the amplitude is determined by 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 plastic is large and the weldment is easy to deform; If the energy is small, it is not easy to weld firmly, and the added pressure cannot be too large. This optimum pressure is the product of the side length of the welding part and the optimum pressure of every 1mm at the edge.
Composition and function of ultrasonic plastic welding machine
Ultrasonic plastic welding machine is composed of pneumatic transmission system, control system, ultrasonic generator, transducer, tool head and mechanical device.
1. Pneumatic transmission system
Including: filter, pressure reducing valve, oil mist, commutator, throttle valve, cylinder, etc.
During operation, the stroke cylinder is driven by the air compressor to drive the ultrasonic transducer vibration system to move up and down. The power air pressure is set according to the welding needs in the medium and small power ultrasonic welding.
2. Control system
The control system consists of time relay or integrated circuit time timer. The main functions are as follows: first, control the pneumatic transmission system to open the gas circuit valve under timing control during welding, pressurize the cylinder to lower the welding head and press the welded object with a certain pressure. After welding, maintain the pressure for a period of time, and then the control system reverses the gas circuit valve to make the welding head rise and reset; The second is to control the working time of the ultrasonic generator. The system realizes the automation of the whole welding process. During operation, only start the button to generate a trigger pulse, which can automatically complete the whole welding process. The sequence of the whole control system is as follows: the power supply starts a trigger control signal pneumatic transmission system, the cylinder pressurizes, the welding head drops and presses the welding, triggers the ultrasonic generator to work, emits ultrasonic and maintains a certain welding time, removes ultrasonic emission, continues to maintain a certain pressure time, depressurizes, the welding head rises, and the welding is completed.
3. Ultrasonic generator
(1) For the high-power ultrasonic plastic welding machine, the generator signal adopts a phase-locked frequency automatic tracking circuit, so that the output frequency of the generator is basically consistent with the resonant frequency of the transducer.
(2) The generator used in ultrasonic plastic welding machine with power above 500W adopts self-excited power oscillator and also has certain frequency tracking ability.
4. Acoustic system for ultrasonic plastic welding machine
(1) Transducer
The acoustic system for ultrasonic plastic welding machine includes three parts: 1 driving part, 2 fixing part and 3 working part. In the above three components, the drive is the core, and the bolt clamped longitudinal vibration transducer is generally adopted, in which the half wavelength longitudinal vibrator is connected with the quarter wavelength longitudinal vibrator, the half wavelength longitudinal vibrator is connected with the half wavelength concentrator to form a full wavelength plastic welding energy converter, and the quarter wavelength longitudinal vibrator is connected with the quarter wavelength concentrator, Form a half wavelength transducer.
(2) Horn
Different tool heads are needed for different welding objects. Whether it is near-field welding or transmission welding, only half wavelength tool head can make the welding end face reach the maximum amplitude. There are two kinds of tool heads with and without amplitude amplification. The tool head of acoustic system for plastic welding machine is usually made of aluminum alloy, and its end face is plated with cemented carbide. When the power is large, it is also made of titanium alloy, and the fatigue strength of this material is more than twice that of aluminum alloy.
Ultrasonic plastic welding machine model and specification:
Ultrasonic plastic welding machine has different welding sizes and specifications due to different application occasions and welding materials. Its output power ranges from tens of watts of manual welding machine to thousands of watts of mainframe, and the frequency is generally in the range of 15KHz to 40KHz.
Applicable industries of ultrasonic plastic welding machine
Ultrasonic plastic welding machine is widely used in automobile industry, electronic industry, medical industry, household appliance industry, non-woven clothing, office supplies, packaging industry, toy industry, etc. For example, body plastic parts, car doors, car instruments, lights, mirrors, sun visors, interior trim, filters, reflective materials, reflective spikes, bumpers, cables, plastic filters for motorcycles, radiators, brake fluid tanks, oil cups, water tanks, oil tanks, air ducts, exhaust purifiers, tray filters; Plastic electronics: prepaid water meter, electricity meter, communication equipment, cordless telephone, mobile phone accessories, mobile phone case, battery case, charger, valve controlled sealed maintenance lead-acid battery, 3-inch floppy disk, U disk, SD card, CF card, USB connector and Bluetooth; Toy stationery: folder, photo album, folding box, PP hollow board, pencil case, ink cartridge, toner drum,; Medical daily use: watch, kitchenware, oral liquid bottle cap, drip bottle cap, mobile phone accessories, golden soft brush, daily necessities, sanitary products, children's products, air mattress, clothes hanger, knife handle, gardening products, kitchen ware, sanitary ware, shower, golden soft brush, shower head, anti-counterfeiting bottle cap, cosmetic bottle cap, coffee pot, washing machine, air dehumidifier, electric iron, electric kettle, vacuum cleaner, Speaker metal cover and civil grille, etc.
