Reflow soldering and wave soldering are two primary methods used in PCB assembly. Each has distinct advantages depending on the application.
Reflow soldering uses hot air or infrared to melt solder paste applied to surface-mount components. It offers precise control and is ideal for fine-pitch components.
Wave soldering passes boards over a wave of molten solder for through-hole components. It is faster but less precise.
Modern SMT lines often use selective wave soldering combined with reflow for mixed-technology boards.