Nordson SELECT

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Selective vs. Manual Soldering

Manual Soldering

In many respects, manual soldering has almost become an obsolete technique since more precise and robust processes have been created.  While once a good technology, manual soldering has for good reason outlived its usefulness and has been for the most part been replaced by selective soldering.

While useful for small series production, today manual soldering is no longer used in mass production for reasons of quality assurance and is no longer even allowed in the automotive industry.  Increasing complexity and ever higher quality standards have contributed to soldering by hand no longer being accepted as an adequate technique.

While still useful for genuine one-off solutions, or repair of individual solder joints, the manual soldering technique has several disadvantages including:

Soldering result is only as good as the person who produces it
Reproducibility is not guaranteed
Extreme flux residues can result from manual soldering
Higher localized thermal load due to small soldering tip and small contact area

Selective Soldering

Selective soldering is a variant of wave soldering used mainly for soldering printed circuit boards that are assembled partly or even entirely with through-hole components. With Nordson SELECT selective soldering machines, nitrogen inerting is standard and the solder pot is designed with titanium material to resist the corrosive effects of aggressive lead-free solder alloys.

Selective soldering in most cases consists of three stages; 1) fluxing or the application of liquid flux, 2) preheating or the printed circuit board assembly, and 3) soldering with a site-specific solder nozzle. Even the programming has been perfectly developed so that operators without any prior knowledge can setup a program within minutes thanks to the Nordson SELECT software.

Due to its inherent process flexibility, selective soldering can be used successfully for soldering a wide range of printed circuit board assemblies and has several distinct advantages including:

• Process optimization can be obtained securely and quickly
• Ensures reliable solder joints without overheating components
• Process reproducibility is guaranteed
• Eliminates use of expensive aperture wave solder pallets or masks