When doing PCBA processing, many customers will encounter the situation that SMT small-batch chip processing plants confirm whether to use lead process or lead-free process, so what is the difference between these two processing processes? In fact, it can be understood from the literal meaning. The difference between lead-free and leaded processes in the soldering process of SMT patch proofing is the lead content in the solder paste. Some friends may think that the lead-free process means that there is no lead at all. , This is also wrong, the solder paste of the lead-free process actually contains lead, but it is relatively small.

So which of these two processing techniques is better? FASTPCBA PCB / PCBA Manufacturer to share with friends in need:

1. The melting point is lead-tin. The melting point is 180~185℃, and the working temperature is about 240~250℃. The melting point of lead-free tin is 210~235°C, and the working temperature is 245°~280°.

2. Alloy composition The tin-lead composition commonly used in SMT chip processing is 63/37, while the lead-free alloy composition is SAC 305, which is Sn: 96.5%, Ag: 3%, and Cu: 0.5%. Although the lead-free process does not mean that there is no lead at all, the content is generally very low.

Third, the cost Everyone knows that the price of tin is more expensive than lead, so the cost of solder will definitely be higher after replacing the lead in the solder with tin. This is the lead-free process compared to the SMT small-batch chip processing factory when calculating the cost One of the main reasons for the expensive lead process.

Fourth, the process. Lead process and lead-free process can be seen from the name. But specific to the process, the solder, components, and equipment used, such as wave soldering furnaces, solder paste printers, and soldering irons for manual soldering, are different.