When customers consult reflow ovenand wave soldering machine welding, they often ask whether you use lead-free welding or leaded welding. We always tell customers that lead-free welding and leaded welding are available, but the prices are different. So what's the difference between lead-free and leaded, and why lead-free welding?
Lead solder paste or lead-free solder paste welding, lead-free solder paste is environmental protection, lead solder paste is not environmental protection, so the difference between lead and lead-free SMT processing is environmental protection and not environmental protection.
1. Different alloy composition:
The composition of tin and lead commonly used in lead processing is 63/37.
The composition of the lead-free alloy is SAC305, that is, Sn: 96.5%, Ag: 3% and Cu: 0.5%.
Lead-free processes cannot be absolutely lead free, but can only contain very low lead content.
2. Different melting points:
The melting point of lead and tin is 180° ~ 185° and the operating temperature is about 240° ~ 250°.
The melting point of lead-free tin is 210° ~ 235° and the operating temperature is 245° ~ 280°.
3. Cost difference:
Tin is more expensive than lead, and the cost of solder increases when the equally important solder is changed to tin. Therefore, the cost of lead-free processing is much higher than that of leaded processing.
The cost of lead-free processing is 2.7 times that of wave soldering and manual soldering, and about 1.5 times that of solder paste for reflow soldering.
Lead-free welding is mainly environmental protection. It is healthier for users and has a much lower impact on the environment. However, the cost of lead-free welding will be higher and the unit price of patch processing will be high. Whether customers need to adopt lead-free welding or lead-free welding should be considered according to the use environment, price and profit of the product, rather than blindly pursuing lead-free welding.
