First, distinguish the quality of the circuit board from its appearance (generally, the appearance of PCB can be analyzed and judged from three aspects;
1. Standard rules for size and thickness.
The thickness of the circuit board to the standard circuit board is different in size. Customers can measure and check the thickness and specification of their own products.
Light and color.
The outer circuit board is covered with ink. The circuit board can play the role of insulation. If the color of the board is not bright, and there is less ink, the insulation board itself is not good.
3. Appearance of weld.
As there are many parts of the circuit board, if the welding is not good, the part will easily fall off the circuit board, which will seriously affect the welding quality of the circuit board. Good appearance, careful identification and strong interface are very important.
Second: high quality PCB needs to meet the following requirements
1. After the components are installed, the phone should be easy to use, that is, the electrical connection should meet the requirements;
2. Line width, line thickness and line spacing of the line shall meet the requirements, so as to avoid heating, circuit breaking and short circuit of the line;
3. The copper under high temperature is not easy to fall off;
4. The copper surface is not easy to be oxidized, which affects the installation speed.
5. No additional electromagnetic radiation;
6. The shape is not deformed to avoid the shell deformation and screw hole dislocation after installation.Now the installation is mechanized, the hole position of the circuit board and the deformation error of the circuit and design should be within the allowable range;
7. The special environment of high temperature, high humidity and resistance should also be considered;
8. The mechanical properties of the surface shall meet the installation requirements;