1.The principle and characteristics of ultrasonic plastic welder
According to the different thermal properties of resin, plastics can be divided into thermoplastics and thermosetting plastics. Ultrasonic plastic welding machine can only weld thermoplastics.
1.1 The principle and device of ultrasonic plastic welder
The principle of ultrasonic plastic welder: Ultrasonic plastic welding is a kind of technology which melts and sticks part of plastic welds together under the action of ultrasonic vibration.
The main components of ultrasonic plastic welding machine are similar to ultrasonic metal welding machine, which are composed of ultrasonic generator&system, machine body and the ultrasonic horn. It includes automatic frequency tracking system, amplitude control system and time control system and some welding mode system.
1.2 The features of ultrasonic plastic welding machine
(1) Unlike the bending vibration required by ultrasonic metal welding, The longitudinal vibration is directly transmitted to the welding area through the upper ultrasonic horn, and the vibration direction of the ultrasonic horn is perpendicular to the contact surface of the welding part. Due to the sound resistance of the contact surface of two welds (i.e. welding area), local high temperature will be produced. Due to the poor thermal conductivity of plastic, heat is not easy to disperse and gather in the welding area, so that plastic melts. In this way, under the action of continuous contact pressure, the weldment contact surface melts into a body, and after curing, the welding spot or welding surface can be formed.
(2) During the plastic welding process, because the ultrasonic vibration energy is transmitted to the welding zone through the upper ultrasonic horn, the distance of ultrasonic vibration energy is different with the shape of the upper ultrasonic horn. According to the distance from the radial end face of the ultrasonic horn to the welding zone, it is divided into near field welding and far field welding. Generally, the distance within 6 ~ 7 mm is called near field welding, and the distance greater than this is called far field welding.
(3) Ultrasonic plastic welding is different from metal welding, the key of ultrasonic plastic welding is the design of welding spot and welding horn. In order to achieve the best effect of ultrasonic plastic welding, it is necessary to choose the appropriate ultrasonic power, welding pressure and welding time, and the rational design ultrasonic horn.
Post time: Apr-06-2022