Analyze the structure of ultrasonic plastic welding machine
Ultrasonic plastic welding machine is mainly composed of four systems: pneumatic drive system, control system, ultrasonic generator, and acoustic system used by ultrasonic plastic welding machine. When welding plastic products, the ultrasonic plastic welding machine neither adds any adhesives, fillers or solvents, 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.
The ultrasonic plastic welding machine is composed of a pneumatic transmission system, a control system, an ultrasonic generator, a transducer, a tool head, and a mechanical device.
1. Pneumatic transmission system
Including: filter, pressure reducing valve, lubricator, commutator, throttle valve, cylinder, etc. When working, the stroke cylinder is first driven by an air compressor to drive the ultrasonic transducer vibration system to move up and down. The power air pressure is adjusted according to the welding needs in the medium and small power ultrasonic welding.
2. Control system
The control system is composed of time relays or integrated circuit time timers. The main functions are: One is to control the work of the pneumatic transmission system to open the gas circuit valve under timing control during welding. The cylinder pressurizes to lower the welding head and press the welded object with a certain pressure. After the welding is completed, the pressure is maintained for a period of time. , And then the control system reverses the gas path valve to reset the welding head; the second is to control the working time of the ultrasonic generator. This system automates the entire welding process. During operation, only the button is activated to generate a trigger pulse, and it can be completed automatically. In the whole process of welding. The sequence of the entire control system is: the power supply activates a trigger control signal pneumatic transmission system, the cylinder pressurizes the welding head to descend and presses the welding to trigger the ultrasonic generator to work, emit ultrasound and maintain a certain welding time, remove the ultrasonic emission, continue to maintain a certain pressure, and depressurize , The welding head rises and the welding ends.
3. Ultrasonic generator
1) For the ultrasonic plastic welding machine with higher power, 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 the ultrasonic plastic welding machine with a power above 500W adopts a self-excited power oscillator, which also has a certain frequency tracking ability.
4. Acoustic system used by ultrasonic plastic welding machine
1) Tool head
Different welding objects require different tool heads. Whether it is near-field welding or transmission welding, only half-wavelength tool heads can achieve the maximum amplitude of the welding end face. Tool heads are available with and without amplitude amplification. Plastic welding machine acoustic system tool heads are usually made of aluminum alloy, and the end surface is plated with cemented carbide. Titanium alloy materials can also be used when the power is high. As a result, the fatigue strength of the material is more than twice that of aluminum alloy.
2) Transducer
The acoustic system of the ultrasonic plastic welding machine includes three parts: 1 driving part 2 fixed part 3 working part. In the above three components, the drive is the core. Generally, a longitudinal vibration transducer clamped by a bolt is used. The half-wavelength longitudinal vibrator is the same as the quarter-wavelength longitudinal vibrator, and the half-wavelength longitudinal vibrator is the same as the half-wavelength concentrator. The connection forms a full-wavelength plastic welding transducer, and the quarter-wavelength longitudinal vibrator is connected with the quarter-wavelength concentrator to form a half-wavelength transducer.
