The Relationship Between Plastic Properties And Ultrasonic Welding
The physical definition of ultrasonic waves is the transmission of vibrations in objects to form waves. The formation of such waves must have two conditions: one is the vibration source, and the other is the communication medium. The classification of waves generally includes the following: According to the vibration direction and communication When the vibration direction is perpendicular to the communication direction, it is called a transverse wave, and when the vibration direction is consistent with the communication direction, it is called a longitudinal wave.
Most of the time, the injection-molded polymers we often use can be welded together by ultrasonic welding, but the difficulty of ultrasonic plastic welding is related to the many durability of the ultrasonic welding machine itself. Fusion separation, the better the ultrasonic welding performance, the harder the plastic. In the flat welding, due to the small oscillation transmission loss, the ultrasonic welding is easier, and the crystalline plastic is from solid to molten state, the temperature range is very narrow, very fast, and the welding performance is poor, Difficult to adjust.
In riveting and insert welding, the ultrasonic welding performance of soft plastics is much easier than that of hard plastics.
At present, various plastic products emerge in an endless stream on the market and in life. Today, I will briefly introduce the ultrasonic welding performance of several plastics that we often see.
1. ABS.HIPS.PMMA.MPPO: rigid amorphous material, easy to conduct ultrasonic frequency of tens of thousands of Hz, especially suitable for long-distance or short-distance ultrasonic welding.
2. PC.PSU: The material has a high melting point and strong hygroscopicity. It should be dried before welding. Otherwise, the moisture in the material will hinder the welding strength, resulting in high welding energy consumption and long welding time.
3.PA: It is a crystalline material with strong hygroscopicity and should be dried before welding.
4.PP.PE: It is a crystalline material with large ultrasonic conduction loss, so long-distance welding is difficult.
Polyvinyl chloride: It is a low melting point and soft material, and the ultrasonic energy loss is large, and it is easy to burn the surface of the weldment during welding.
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