The melting point of the solder is lower than that of the material to be welded, so that the components will be welded through the intermolecular connection on their surface without being melted.

       Welding can be divided into soft soldering and hard soldering, the soft soldering temperature is lower than 450 ℃, and the hard soldering temperature is higher than 450 ℃. Hard welding is generally used for metals such as silver, gold, steel, and copper. Its welding point is much stronger than soft welding, and its shear strength is 20 to 30 times that of soft welding. The term soldering is generally used for both thermal joints, since in both cases molten solder is written into an elongated gap between two clean and close solid metal surfaces to be installed.

       Welding ensures the continuity of the metal. On the one hand, the two metals are connected to each other by bolted connection or physical attachment, which is shown as a robust metal whole, but this connection is discontinuous. Sometimes if there is an oxide insulating film on the surface of the metal, they even Right or wrong physical contact. Another disadvantage of mechanical coupling compared to welding is that the contact surface continues to oxidize, resulting in an increase in resistance. Additionally, tremors and other mechanical shocks can loosen the joint. Welding eliminates these problems, the welding parts do not move relative to each other, the contact surface does not oxidize, and the continuous conduction method is maintained. Welding is a fusion process between two metals. When the solder is molten, it will dissolve some of the metal in contact with it, and the surface of the metal to be welded often has a thin layer of oxide film that cannot be dissolved by the solder. The flux is used to remove it. this oxide film.

       To control the welding quality of the ultrasonic plastic welding machine, it is necessary to understand the quality problems that the ultrasonic plastic welding machine is prone to produce in the welding process, and then deal with it accordingly. After skilled operation, it can be easily controlled in the actual production of ultrasonic welding, especially for products. For personal consumer products that require high quality in terms of appearance and function, quality is still a difficult issue to control. Summarizing the past experience, it is found that some quality problems that are generally more likely to occur are: low strength, scars or cracks on the surface of the product, distortion or self-coloring of the product, damage to the internal parts of the product or deformation due to kneading, and burrs on the product , After the product is welded, the size cannot be controlled within the tolerance, the product is offset, and the water and gas sealing function requirements cannot be achieved after ultrasonic welding.