Lead-free soldering

Lead-free soldering has become the standard in electronics manufacturing over the past two decades. Thanks to the European RoHS directive, most production today uses lead-free solders.

What is lead-free soldering?

Soldering with solders that contain no lead, usually based on tin-copper-silver (SAC). These alloys have a higher melting point than classic tin-lead.

Why the switch?

The RoHS directive restricts hazardous substances, including lead, in electronics – for environmental and health reasons.

Difference between leaded and lead-free solder

Lead-free solder melts higher, wets less well and gives more matte joints. It needs more heat and a better flux.

Temperature for lead-free soldering

Around 350–380 °C at the tip is common – depending on the joint. More important than high temperature is the station fast heat recovery.

Which soldering stations are suitable?

Stations with fast control and strong heat recovery. The article how to choose a soldering station helps; browse the range under soldering equipment.

The importance of good flux

Lead-free solder wets less well, so an active, high-quality flux is crucial for clean joints.

How to recognise a good joint?

Evenly wetted, smooth, without cracks – more matte with lead-free than with leaded, which is normal.

Common mistakes

Too low a temperature, poor flux and overheating. More in the most common soldering mistakes.

Lead-free soldering in SMT production

In SMD production, lead-free is the standard – with a precise temperature profile in reflow and rework.

Tip life in lead-free soldering

Higher temperatures wear tips faster; proper care extends life – see extending the life of soldering tips.

Conclusion

Lead-free soldering needs more heat, good flux and tip care. Find more guides in the ESD Guide.