The ultrasonic plastic welding machine is more and more widely used in the plastic welding industry, we have a lot of plastic products in daily life which can be welded by ultrasonic plastic welding machines, such as water use plastic cups, and mobile phone charger heads, plastic toys, car doors. It can be said that plastic is the most common material we use in our everyday life. So far, known plastic materials have nearly 100 kinds, widely used plastics are polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS), ABS resin, and polyethylene terephthalate (PET). Plastics can be divided into crystalline and amorphous polymers.
Amorphous polymer (ABS, PC, PS, PVC, PMMA, etc.): the molecular arrangement is disorderly, and there is an obvious temperature that makes the material gradually soft, melting, and flowing (Tg glass transition temperature). Such plastics typically transmit ultrasonic vibrations efficiently and weld well over a fairly wide range of pressures/amplitudes.
Crystalline polymers (PE, PP, POM, PA6, PA66, PBT, PET, etc.): the molecules are orderly arranged and have an obvious melting point (Tm melting temperature) and refreezing point. Solid crystalline polymers are elastic and can absorb some of the high-frequency mechanical vibrations. So this kind of plastic is not easy to transmit the ultrasonic vibration energy to the bonding surface, demands a higher amplitude, and high energy (high melting heat) is needed to put half a crystalline structure interrupted so that the materials from crystalline state to viscous flow state, this also determines the obvious melting point of this kind of material. Once the molten material leaves the heat source, the temperature decreases to a certain extent, leading to the rapid solidification of the material.
Of course, some of the different plastic materials can be ultrasonic welded, please refer to the following table:
