In the process of PCBA production, it is easy to have poor soldering. For example, if the tin thickness is too low, or the tin thickness is too high, the poor soldering will directly cause the circuit board to fail to leave the factory. Therefore, tin is an indispensable part of PCB production. As the saying goes, it is necessary to tie the bell to untie the bell. If you want to solve the problem of poor soldering, you must know the reason for the poor tin on the PCB. Let's introduce it today.

Analysis of the causes of poor tin on PCB:
1. There are particulate impurities in the plating layer on the board, or grinding particles are left on the surface of the circuit during the manufacturing process of the substrate.
2. There are sundries such as grease and impurities on the surface of the board, or there are residual silicone oil
 3. There are flakes on the surface of the board and no tin is applied, and the plating layer on the board surface has particulate impurities.
4. The high-potential coating is rough, there is burning phenomenon, and there are flakes on the surface of the board, which can not be tinned.
5. The tin surface of the substrate or parts is seriously oxidized and the copper surface is dull.
6. The coating on one side is complete, and the coating on the other side is poor, and there are obvious bright edges on the edges of the low-potential holes.
7. There are obvious bright edges on the edges of low-potential holes, and the high-potential coating is rough and burnt.
8. There is no guarantee of sufficient temperature or time during the soldering process, or the flux is not used correctly
9. Tin can not be plated on a large area at low potential, and the surface of the board is slightly dark red or red, with a complete coating on one side and a poor coating on the other side.

The above nine points are the reasons that may lead to poor tinning in our PCB board production process. Only by grasping and realizing which part of the tinning process is wrong, or not paying attention to find the root cause, Flexible PCB can we better prescribe the right medicine.