LEAD-FREE SOLDER PASTE

Since the RoHS regulation has been in force, electronic assemblies for most applications must be manufactured lead-free. SAC305 has become the standard alloy in this regard. Currently, it is the optimal and most widely used alloy for most applications. Its silver content of 3% ensures good wetting properties. To optimize costs, other alloys with lower silver content are used as well, but more commonly in the consumer sector.

Melting point of lead-free solder paste

In the production process, the high melting range of the SAC305 alloy can sometimes be problematic. The required high peak temperatures can lead to a thermal overload in the production of some parts. Therefore, for temperature-critical components, the use of low-temperature solder pastes can be necessary.

Solder paste recommendations

Most of our solder pastes are no-clean solder pastes. That means that the flux residues can remain at the solder joint after soldering. Our general recommendation is the NP303-COSMO-LH-T4 solder paste or NP303-COSMO-LH-T5 depending on the stencil thickness. If cleaning does become necessary, with these solder pastes, the flux residues can easily be removed.

Advantage of lead-free solder paste

The big advantage is that the solder paste no longer contains lead, a toxic heavy metal. Especially if disposed improperly, lead enters the environment and damages the nervous system, impairs the formation of blood, causes gastrointestinal health problems, kidney damage, and is reprotoxic.