Ultrasonic plastic welding machine consists of pneumatic transmission system, control system, ultrasonic generator, transducer and tool head and mechanical device.
Pneumatic transmission system
Including: triplex (filter, decompression crucible, oil mister), commutator, throttle, cylinder. The working process is as follows. Firstly, the stroke cylinder is driven by the air compressor, and the air pressure is set according to the welding needs in the actual working operation. The cylinder process (the amplitude of the ultrasonic vibration system) is generally tens of mm to several hundred mm.
2. Control system
The control system consists of a time relay or a time timer of the integrated circuit. Its main function: First, control the pneumatic drive train
Work in the system to open the gas country door under the control of timing during the welding, the pressure of the cylinder will lower the welding head, and the workpiece will be pressed with a certain pressure. After welding, it will be kept for a period of time, then the control system will take the gas path. The idle door is reversed to reset the head; the second is to control the working time of the ultrasonic generator. This system automates the entire welding process. The operator can automatically complete the entire welding process by simply activating the button to generate a trigger pulse. The order of the whole control system is: power start-trigger control signal-a pneumatic transmission system works, cylinder pressure welding head descends and presses the weldment → triggers the ultrasonic generator to work, emits ultrasonic waves and maintains a certain welding time → removes ultrasonic emission → continues Keep a certain pressure time, a pressure back, the welding head rises → the end of welding
3. Ultrasonic generator
Ultrasonic generators for ultrasonic welding are currently in the following two forms.
(1) Ultrasonic plastic welding machine with large power, the signal of the generator is usually automatically locked by the phase-locked frequency to make the generator lose
The frequency of the output is substantially the same as the resonant frequency of the transducer. The final stage power amplifier uses a high-efficiency VMOS class D amplifier. The ultrasonic generator with a power of more than 1 kW often uses a power synthesis circuit.
(2) Ultrasonic plastic welding machine generators with power below 500W, often using self-excited power oscillators, also have certain
Frequency tracking capability.
4. Acoustic system used in ultrasonic plastic welding machine
(1) Transducer
The acoustic system for ultrasonic plastic welding machine consists of three parts: 1 drive part; 2 fixed part; 3 working part, for the medium and small power ultrasonic transducer, the drive part is often combined with the fixed part, or the fixed part is combined with the working part. , thereby reducing the body
Accumulate, reduce weight. Among the above three components, the drive is the core, and generally uses a bolt-clamped longitudinal vibration transducer in which a half-wavelength is transmitted to the vibrator and a quarter-wavelength longitudinal vibrator. The half-wavelength longitudinal vibrator is connected to the half-wavelength concentrator to form a full-wavelength plastic welding transducer. The quarter-wavelength longitudinal vibrator is connected to a quarter-wave concentrator to form a half-wavelength transducer.
(2) Tool head
Different tool heads are required for different welding objects. Whether it is near field soldering or transmission soldering (far field), only half wavelength
The tool head is used to achieve the maximum amplitude of the welded end face.
The tool head has two types with amplitude amplification and no vibration amplification. Sound system tool head for plastic welding machines, the materials used are usually
For aluminum alloy, the end face is plated with hard alloy. When the power is large, it is also made of titanium alloy material. The fatigue strength of the material is more than twice as high as that of the alloy.