PCB News - Which one is better for pcb with lead spray tin or lead-free tin spray?

Which one is better for PCB with lead spray tin or lead-free tin spray?

Tin spraying is the form of pad coating, which is one of the most common PCB board processing methods. There are two types of tin spraying: lead spraying and lead-free spraying. The standard for spraying tin thickness in the industry is 20uM. Some customers do not understand the difference between lead-free and lead-free spray tin, so which is better for PCB with lead-spray tin or lead-free tin-spray? Today, the editor of the PCB factory tells everyone that there are lead spray tin and lead-free tin spray.

(1) From the literal meaning, we can know that lead-free tin spray is an environmentally friendly type, and lead-free tin spray is a non-environmentally friendly type. The lead content of lead-free does not exceed 5, while the lead content of lead reaches 37, which is more than seven times the lead content of lead-free.

(2) The color of the appearance can also distinguish between lead-sprayed tin and lead-free tin-sprayed. Generally, the lead-sprayed soldering pad is brighter, and the lead-free sprayed tin soldering pad is darker. Leaded tin spray has better wettability than lead-free ones, and some tin sprays are more cost-effective than lead-free ones. It is more cost-effective to choose lead in terms of price. It is better to choose lead-free spray tin for those who have higher requirements for environmental protection. iPCB is a high-tech manufacturing enterprise focusing on the development and production of high-precision PCBs. iPCB is happy to be your business partner. Our business goal is to become the most professional prototyping PCB manufacturer in the world. Mainly focus on microwave high frequency PCB, high frequency mixed pressure, ultra-high multi-layer IC testing, from 1+ to 6+ HDI, Anylayer HDI, IC Substrate, IC test board, rigid flexible PCB, ordinary multi-layer FR4 PCB, etc. Products are widely used in industry 4.0, communications, industrial control, digital, power, computers, automobiles, medical, aerospace, instrumentation, Internet of Things and other fields.

(3) The melting point of lead is around 183 degree Celsius, so the temperature of the tin spraying furnace should be controlled at 245 degree Celsius-260 degree Celsius, the peak temperature should be controlled at 250 degree Celsius, and the reflow temperature should be controlled at 245 degree Celsius-255 degree Celsius.

The melting point of lead-free is 218 degree Celsius, so the temperature of the tin spraying furnace should be controlled at 280 degree Celsius-300 degree Celsius, the peak temperature should be controlled at 260 degree Celsius, and the reflow temperature should be controlled at 260 degree Celsius-270 degree Celsius.

Because lead will increase the activity of tin in the soldering process, lead-tin wire is better than lead-free tin wire; however, the melting point of lead-free tin spray is higher than that of lead-tin spray, so lead-free tin spray soldering The point is much stronger than the lead-sprayed solder point. (Shenzhen Circuit Board Factory)