Lead free test process inspection standard PCB board has the difference between lead and lead-free

Date：2022-04-07 15:20:44 Views：1418

With the continuous development of the electronic industry, the demand for PCB board also increases. The common surface processes of PCB board include tin spraying, gold deposition, gold plating, OSP, etc. in fact, tin spraying is divided into lead-free tin spraying and lead-free tin spraying. Next, we will mainly talk about the inspection standards of lead-free process and introduce the difference between lead-free and lead-free PCB board.

From the appearance, the surface of the circuit board with lead solder looks bright white, while the lead-free solder looks light yellow, which is actually because the lead-free solder contains copper.

From the hand feel, when you wipe the solder with your hand, the lead-free solder will leave a light yellow trace on your hand, while the lead solder will leave a black trace.

From the perspective of composition, the main elements of lead solder are tin and lead, while lead-free solder contains less than 500 ppm lead. Lead-free solder generally contains tin, silver or copper metal elements, soLead free is not 0 lead, but the content of lead is very small, reaching the standard content of environmental protection.

In terms of use, lead solder is used for the welding of lead products, and its tools and components are lead. Lead free solder is used for lead-free products exported to Europe, America and other countries. Its tools and components must be lead-free.

PCB has the difference between lead and lead-free

1. Weldability

The melting point of lead-free process is 218 degrees, while that of lead tin spraying is 183 degrees. The solderability of lead-free tin welding is higher than that of lead tin welding. The firmness of lead containing process is relatively poor, and false welding is easy to occur in welding. However, due to the relatively low temperature of lead, the thermal damage to electronic products is less, and the surface of PCB is brighter.

2. Cost variance

In the lead-free process, the tin bar used in wave soldering and the tin wire used in manual soldering have increased the cost by about three times; The cost of solder paste in reflow soldering is increased by about 2 times.

3. Security

As a toxic substance, long-term use of lead causes harm to human health and the environment.

Even though the lead process has the characteristics of low price and brighter surface, under the pressure of policy and environmental protection in recent years, the living space of lead has become smaller and smaller. The main reason is the sewage discharge of PCB lead process and the disposal of lead PCB products, whether buried or burned, the lead components will eventually return to the environment through the media, resulting in serious lead pollution, It brings great harm to the environment and human survival. So today's content is shared here. If you think the content is helpful to you, welcome to pay attention to Chuangxin testing, and we will provide you with more industry information!