Introduction To The Selective Welding Technology For Printed Circuit Board (PCB)

Reviewing the process development of the electronics industry in recent years, it can be noted that a very obvious trend is reflow soldering technology. In principle, traditional inserts can also be reflow welding process, which is commonly known as through-hole reflow welding. The advantage is that it is possible to complete all solder joints at the same time, keeping production costs to a minimum. However, temperature-sensitive elements limit the application of reflow soldering, both in cartridge and SMD. Then people turn to the choice of welding. Selective soldering can be used after reflow soldering in most applications. This will be an economical and efficient method of soldering the remaining cartridge and is fully compatible with future lead-free soldering.

Process characteristics of selective welding

The process characteristics of selective welding can be understood by comparing it with wave soldering. The most obvious difference between the two is that in wave soldering, the lower part of the PCB is completely immersed in the liquid solder, whereas in selective soldering, only certain areas are in contact with the solder wave. Since the PCB itself is a poor heat conduction medium, it will not heat and melt the solder joints adjacent to the components and PCB area during welding. Flux must also be applied before welding. In contrast to wave soldering, flux is only applied to the lower part of the PCB to be soldered, not the entire PCB. In addition, selective welding is only applicable to the welding of cartridge components. Selective welding is a completely new method. A thorough understanding of the selective welding process and equipment is necessary for successful welding.