There are many factors affecting ultrasonic plastic welding effect, and we are going to talk about the materials in this article.
1. The ultrasonic welding material differences
The welding material difference affects the ultrasonic welding quality, adding fiber and other fillings can improve the hardness of materials, which is conducive to the transmission of ultrasonic, adding fillers can improve the strength of ultrasonic welding joints under appropriate technological conditions.
2. The ultrasonic welding material surface roughness
Increasing the surface roughness can not only reduce the acoustic impedance, improve the surface energy flow density, but also can improve ultrasonic welding quality. By using the membrane material with rolling pattern on the surface, higher ultrasonic welding quality can be obtained, and in this way, the the strength of ultrasonic welding joint can be higher several times than PP one with smooth surface.
3. The ultrasonic welding line width
The increase of the ultrasonic welding line width can decrease the strength of ultrasonic welded joint; because with the increase of the ultrasonic welding line width, the stress concentration at the edge of ultrasonic welded joint increases, the microcracks appear at the edge increase, and the joint strength decreases.
4. The influence of the distance from the welding surface to the welding joint
When the distance from the ultrasonic welding surface to the welding joint reaches the half-wavelength value, the strength of the ultrasonic welding joint reaches the maximum. Ultrasonic wave mainly propagates longitudinal-wave in plastics, and the peak value of the maximum longitudinal-wave mostly appears in the half wavelength. When it is close to the half wavelength, the heat energy of ultrasonic wave propagates to the ultrasonic welding interface, and good ultrasonic welding joints can be obtained. The quality of ultrasonic welding is directly proportional to the elastic modulus, friction coefficient and thermal conductivity, and inversely proportional to its density, specific heat and melting point.
5.The melting point and surface friction resistance of material
The key of ultrasonic welding quality is related to the melting point and surface friction resistance of material. This parameter is not the same because of the different materials and temperature, their transformation in the ultrasonic welding process will harm the temperature, shear force and deformation of the ultrasonic welding area, and then harm the quality of ultrasonic welding.
Nowadays, some plastics like PE, PC, ABS, PP, PVC, proline, nylon, polyester can get the best effect through ultrasonic welding, now these plastics are also used in the market the most widely. After the above understanding, we believe that the ultrasonic mold of ultrasonic welding machine can reasonably choose materials, avoid unnecessary failures, improve product quality, reduce operating costs, and greatly improve production efficiency.
Post time: Mar-23-2022