Ultrasound Welding System for Better Punching Effect
With the continuous development of industrial technology, plastic products have been widely used. In engineering, the composition of the material is the same as that of the welded material, but the strength label of the material is one grade higher than that of the welded material, so the welding strength can be guaranteed. So, what are the factors that influence the quality of plastic welding?
In general, pressure, time, and heat absorption (melting capacity) are the main factors affecting welding quality.
In the process of plastic welding, proper pressure should be applied on the welding surface, which not only promotes the transition of the welding material from elasticity to plasticity, but also promotes the diffusion of molecules and squeezes the residual air in the weld. Thus, the sealing performance of welding joint is better.
Welding time assurance is very important, it should have appropriate hot melt time and adequate cooling time. When the thermal power is constant, the virtual welding will occur when the time is not enough, and the excessive time will result in the deformation of the welding piece, the slag overflow, and sometimes the heat spot will appear in the non-welded part. Therefore, it is necessary to ensure that the welding surface absorbs enough heat to achieve the state of full melting, so as to ensure the full diffusion and fusion between molecules, and at the same time, to ensure sufficient cooling time for the weld to reach sufficient strength.
3. Amount of molten
Only when the melting time and thermal power are adjusted in a coordinated way can the optimal melting amount be obtained, and enough molecules can be fused to eliminate the phenomenon of virtual welding. In addition to the technical level of welding equipment and operators, various factors inside and outside the plastic have certain influence on the welding quality and should be paid attention to.
What is the other Influencing Factors on Welding Quality of Plastics?
1) Hygroscopicity of plastic
If a wet plastic product is welded, the moisture contained in it will turn into vapor after being heated, and bubbles will appear on the welding surface, which will weaken the sealing performance of the welding surface. Materials with more severe moisture absorption include PA, ABS and PMMA. Articles made of these materials must be dried before welding in order to ensure the quality of welding.
2) Filler in plastic
Such as glass fiber, talc, mica and so on, they change the physical properties of the material. The content of filler in plastics has a great relationship with the weldability and welding quality of plastics. Plastics with less than 20% filler content can be properly welded without special treatment. When the filler content exceeds 30%, due to the insufficient proportion of the surface plastic, the intermolecular fusion is insufficient and the sealing performance is reduced.
3) Cleaning of welding surfaces
The welding surface must be kept clean and free of impurities to ensure sufficient welding strength and airtightness.