电路实验焊接技术（Circuit experiment welding technology）.doc

电路实验焊接技术（Circuit experiment welding technology） This article is contributed by Mao Yuhan Ppt documents may experience poor browsing on the WAP side. It is recommended that you first select TXT, or download the source file to the local view. welding technique In the process of product design, it is often necessary to make circuit debugging experiments, which requires electrical and electronic technicians to master welding technology. Basic knowledge of welding 1. welding concept and classification Welding is the use of heat or pressure or both and other means, with or without filling materials, the separation of the two parts of the metal, with the help of diffusion atoms and interaction between atoms, and the formation of a permanent connection process. A junction formed by welding is called a solder joint. According to the state of the metal and the characteristics of the welding process, the welding methods can be divided into three categories: fusion welding, pressure welding and brazing. Brazing is divided into brazing and soldering according to the melting point of the solder. The solder whose melting point is higher than 450 degrees is called brazing, and the solder whose melting point is lower than 450 degrees is called soldering soldering. The 2. mechanism is actually the process of soldering soldering solder, solder, welding in welding heating under the effect of physical and chemical processes that occur between the different metal surface mutual infiltration, diffusion, combined with the final form of multi organizational layer. The mechanism can be expressed by soldering crystallization and solidification infiltration, diffusion and interfacial layer three process. Wettability is generally expressed by wetting angle theta, and the wetting angle is the angle between the tangent of the solder outer circle and the weld face at the junction of the weldment surface. When theta 90 degrees are solder non wetted weldment, theta =90 degrees is poor wetting perfor