During the reflow soldering process, printed circuit boards assembled with SMD and THR components, are passed at a constant speed through various heating zones of a furnace (preheating, reflow soldering and furnace cooling).
In contrast to wave soldering, components and their plastic packages are exposed to the same temperatures as the metallic contacts to be soldered.
Electrical components, printed circuit boards and solder joints are heated either by infrared, convection or a vapor phase processes. In order to avoid oxidation of the solder pads on the printed circuit, this process can also be conducted under inert atmosphere.
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Wave soldering processes are suitable for soldering conventional components.
A conveyor system moves the PCB through the soldering system at a constant speed. Upstream in the wave soldering system, the PCB and its components pass through the fluxer.
Downstream in the preheating zone, the solvents contained in the fluxer are vaporized thus activating the flux. Liquid solder is continuously pumped flowing over edges, through holes or into gaps, forming a wave of solder. This solder wave conveys and wets the underside of the printed circuit. Capillary forces raise the solder through the space between hole and component lead (solder pin) forming the characteristic solder meniscus.
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The shown tables represents two solder temperature profiles compliant with EN 61760-1. Due to the various customer-specific parameters (e.g. soldering system, solder paste, component arrangement and orientation) the profiles are only recommendations and should be used accordingly.