With the widespread use of
lead-free solder paste in the electronics industry, many people are wondering, does it mean that all PCBA boards are lead-free and use lead-free solder paste? In fact, this is not the case. Often times, cost issues or other issues will be considered, which will cause many circuit board manufacturers to continue to use lead-based processes. So how to distinguish whether a PCB board is lead-free or leaded?
Practical method:
First, in terms of appearance: on the circuit board, the surface of the lead solder appears to be bright white, while the lead-free solder appears light yellow (because the lead-free solder contains copper metal).
Second, in terms of hand feel: rubbing the solder with your hands, lead-free solder will leave light yellow marks on your hands, while lead solder will leave black marks on your hands.
Third, in terms of composition: leaded solder contains tin and lead, while lead-free solder contains less than 500PPM), and lead-free solder generally contains tin, silver or copper metal elements.
Fourth, in terms of use: lead solder is used for soldering lead products, and the tools and components used in it are all lead. Lead-free solder is used to solder lead-free products exported to Europe, America and other countries, and the tools and components used must be lead-free.
Through the above four methods, we can easily identify which solder paste soldering process is used for the PCB board.