/Printed circuit board “lead” craft characteristics
In PCB printing manufacturing, the production craft is an extremely important link. Generally, the pcb craft has osp, immersion gold, gold plating, spray tin and so on. Among them, spray tin is the most common craft in PCB production. Everyone is familiar with it. In the tin-spraying craft, it is divided into two types: “lead-sprayed tin” and “lead-free spray tin”. What is the relationship between the two? What is the impact on the PCB industry?FASTPCBA will talk about it today.
Second, the performance difference
First, the development history
“Lead-free” was developed on the basis of “lead”. Since the 1990s, countries such as the United States, Europe and Japan legislated for the application of lead in industry and conducted research on lead-free welding materials, develop with related technologies . .
The lead-free craft has a melting point of 218 degrees, while the lead-spray tin has a melting point of 183 degrees. The lead-free soldering is more solderable than leaded soldering. The lead craft is relatively weak and the solder joints is prone to virtual welding. However, due to the relatively low temperature of lead, the thermal damage to electronic products is pretty small and the surface of the PCB is brighter.
In the lead-free craft, the tin bars used for wave soldering and the tin wires used for manual soldering have increased the cost by about 3 times; the solder paste used in reflow soldering has increased the cost by about 2 times.
Lead as a toxic substance, long-term use is harmful to human health and the environment.
Even if the lead craft has the characteristics of low price and brighter surface, but in recent years, under the pressure of policy and environmental protection, the living space of lead is getting smaller and smaller. The main reason is the discharge of sewage from PCB lead craft and lead. After the PCB product is disposed, whether it is treated by burial or incineration, the lead component will eventually return to the environment through the medium, resulting in serious lead pollution, which will greatly harm the environment and human survival.
In the craft of manufacturing PCB, FASTPCBA has turned lead to lead-free roads, strengthened innovation in energy saving and emission reduction, and comprehensively applied “big data” and “cloud computing” to improve resource utilization and achieve automated management and monitoring of the production line, while achieving development, it is also necessary to protect the environment.
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