Introduction of working principle and components of ultrasonic welding machine

Update: 12-05-2020

The principle of ultrasonic plastic welding is that the […]

The principle of ultrasonic plastic welding is that the generator generates 20KHz (or 15KHz) high-voltage and high-frequency signals. The signal is converted into high-frequency mechanical vibration through the energy conversion system, which is added to the plastic product workpiece, through the workpiece surface and between the molecules. Friction causes the temperature transmitted to the interface to rise. When the temperature reaches the melting point of the workpiece itself, the workpiece interface is quickly melted and then filled in the gap between the interfaces. When the vibration stops, the workpiece is cooled and shaped under a certain pressure at the same time. Achieve perfect welding.
The new 15KHz ultrasonic plastic welding machine has a unique effect on welding softer PE and PP materials, as well as super-large diameter and super-long plastic weldments, which can meet the needs of various products, and can produce efficiency and product grades for users. contribution.

Components of ultrasonic welding machine:

The ultrasonic welding machine is mainly composed of the following parts: generator, pneumatic part, program control part, and transducer part.
1. The main function of the generator is to convert the power supply with a power frequency of 50HZ into high-frequency electric waves of high frequency (for example, 20KHZ) by using electronic circuits.
2. The main function of the pneumatic part is to complete the pressure work such as pressurization and holding pressure during the processing.
3. The program control part controls the work flow of the whole machine to achieve a consistent processing effect.
4. The transducer part is to convert the high-voltage electric wave generated by the generator into mechanical vibration, and then reach the processed surface through transmission, amplification.
What are the welding methods for ultrasonic welding machines?
1. Welding method
Under moderate pressure, the welding head that vibrates with ultra-high frequency of ultrasonic waves generates frictional heat at the joint surface of the two pieces of plastic and instantly melts the joint. The welding strength is comparable to that of the body. The use of suitable workpieces and reasonable interface design can achieve watertight Airtight, free of inconveniences caused by the use of auxiliary products, and achieve efficient and clean welding.

2. Riveting method
The ultrasonic welding head with ultra-high frequency vibration is pressed against the protruding tip of the plastic product, so that it instantly melts into a rivet shape, and the materials of different materials are mechanically riveted together.

3. Embedding
With the help of the welding head and proper pressure, the metal parts (such as nuts, screws, etc.) are instantly squeezed into the reserved plastic holes and fixed at a certain depth. After the completion, regardless of the pulling force and torque, it can be comparable to the traditional mold. The strength can avoid the defects of damage to the injection mold and slow injection.

4. Forming
This method is similar to the riveting welding method. The concave welding head is pressed against the outer ring of the plastic product. After the ultrasonic ultra-high frequency vibration of the welding head is melted, the plastic is melted and formed and covered with metal objects to fix it, and the appearance is smooth and beautiful. The method is mostly used in the fixation of electronics and speakers, and the fixation of lenses in cosmetics.
5. Spot welding
A. Welding the two pieces of plastic in a separate point does not require a pre-designed welding wire to achieve the purpose of welding.
B. For relatively large workpieces, it is not easy to design the welding line to carry out spot welding, and to achieve the welding effect, it can spot weld multiple points at the same time.

6. Cutting and sealing
Using the principle of ultrasonic instantaneous vibration, the chemical fiber fabric is cut, and its advantages are smooth and clean, without cracking or drawing. High-frequency and ultrasonic are two different concepts. High-frequency refers to electromagnetic waves with a frequency greater than 100Khz, and ultrasonic refers to sound waves with a frequency of more than 20 kHz. High-frequency welding principle and welding principle are also different from ultrasonic wave. High-frequency wave uses high-frequency electromagnetic field to make the molecules inside the material collide with each other to produce high temperature to achieve the purpose of welding and welding. Ultrasonic wave uses the principle of friction to generate heat. To achieve the purpose of welding and welding.