3. The process characteristics of selective soldering can be better understood through comparison with wave soldering. The most noticeable difference between the two methods is that, in wave soldering, the lower part of the PCB is fully immersed in liquid solder, whereas, in selective soldering, only specific areas of the PCB come into contact with the solder wave. Since the PCB itself is a poor conductor of heat, it prevents the solder joints of adjacent components and PCB areas from overheating and melting during soldering. Additionally, flux must be pre-coated before soldering; however, in selective soldering, the flux is applied only to the targeted areas of the PCB rather than the entire board. Furthermore, selective soldering is specifically designed for soldering through-hole components. This method is relatively new, and a comprehensive understanding of the selective soldering process and equipment is essential for successful application. Currently, the country is imposing increasingly stringent environmental protection standards and intensifying regulatory efforts, presenting both challenges and opportunities for PCB manufacturers. If PCB factories are committed to addressing environmental pollution, then FPC flexible circuit board products can lead the market, offering PCB manufacturers further development opportunities. The Internet era has disrupted traditional marketing models, consolidating resources through digital platforms, which has also accelerated the development of FPC flexible circuit boards. As this development progresses, environmental issues will increasingly confront PCB factories. However, with the advancement of the Internet, environmental protection and environmental informatization have also seen significant progress. Environmental information data centers and green electronic procurement are gradually being integrated into actual production and operational practices.