WaveLöten

WaveLöten is a manufacturing process used to attach electronic components to printed circuit boards by passing the boards over a molten solder wave. It is especially suited for through-hole assemblies and mixed-technology boards, where some components are not easily soldered by surface-mount reflow alone. While its use has declined for all-SMT designs, wave soldering remains common in production lines that combine through-hole parts with surface-mounted devices.

The process typically starts with flux application to clean the copper surfaces and prevent oxidation. The boards are preheated to activate the flux and reduce thermal shock, then conveyed over a controlled molten solder wave. Front and heel sections of the wave ensure fillet formation on component leads and solder joints. After exiting the wave, excess solder is removed with defined post-bridging strategies such as solder thieves. Flux is often no-clean, though water-soluble fluxes may require cleaning. Modern systems use leaded or lead-free alloys, with common choices including Sn-Pb and SAC alloys, and operate at temperatures appropriate for the chosen alloy.

Equipment consists of a solder kettle, a wave-generating nozzle, a preheater zone, a flux application system, and a board conveyor with entry/exit guides. Process control focuses on solder temperature, dwell time, and wave height to minimize bridging, icicles, and voids, while protecting heat-sensitive components.

Design considerations include spacing between pads, component lead length, and the avoidance of excessive heat on delicate parts. While highly fine-pitch SMT boards increasingly use selective or full reflow, WaveLöten remains a robust method for hybrids and boards with through-hole elements. Environmental and regulatory factors influence the choice between leaded and lead-free solders.