Principle of Handheld Ultrasonic Welding Machine In the ultrasonic welding process, the hand-held ultrasonic welding machine can increase the vibration amplitude of the high-frequency vibration wave through the amplifier, and then load it into the upper mold, which will be enhanced by the upper mold. The frequency vibration wave acts on the product, so that the instantaneous high-frequency vibration between the products can not generate high heat, so as to achieve the purpose of welding the products together.
The hand-held ultrasonic welding machine consists of a basic structure such as a high-frequency current converter, a piezoelectric transducer, an amplitude modulator, an electrode arm or an acoustic rod.
High frequency current converter
The main function of the high-frequency current converter is to convert the input low-frequency current into the output high-frequency current, the frequency range is the same as the ultrasonic frequency range, and the ultrasonic welding often uses the output frequency of 20khz.
2. Piezoelectric converter
The function of a piezoelectric transducer is to convert electrical energy into mechanical vibrational energy while the frequency remains the same. Usually done by a piezoelectric or frequency converter, it uses asymmetric crystals, such as natural quartz wafers, synthetic lithium titanate or tantalum wafers, etc., which will change with current frequency when it is in an alternating electric field. Mechanical deformation or dimensional shrinkage at the same frequency is also called the piezoelectric effect. Using the piezoelectric effect of such chips, high frequency electrical energy can be converted into ultrasonic energy.
3. Modulator
The piezoelectric material expands or contracts under the action of an alternating voltage to generate high-frequency vibration, but the degree of such vibration is not large, and is about (0.01-0.02 mm). This is obviously not enough to produce a good weld, so a part called a modulator is used on the hand-held ultrasonic welder to increase the amplitude. This is a half-wave aluminum or titanium resonator.
4. Electrode arm or sonic rod
The electrode arm or sonic rod, also known as the ultrasonic mold, is a tool for transferring energy to the plastic product to be welded, usually made of an alloy such as aluminum or titanium. Its function is to increase the amplitude of the end of the electrode arm and transmit the high-frequency vibration and pressure to the welded part of the component. The typical vibration range is (0.05-0.12) mm. The design of the electrode arm is a complicated matter, except that it is shaped to match the contour of the product to be welded, and the frequency of the welding product should be matched to that of the hand-held ultrasonic welding machine. In order to ensure the smooth progress of the welding process, the electrode arm is generally designed and manufactured by a hand-held ultrasonic welding machine manufacturer or an acoustic research institution.