First: distinguish the quality of the circuit board from the appearance
In general, the appearance of PCB can be analyzed and judged from three aspects;
1. Standard rules for size and thickness.
The thickness of circuit board to standard circuit board is different, customers can measure and check according to the thickness and specification of their products.
2. Light and color.
The external circuit boards are covered with ink, and the circuit board can play an insulating role. If the color of the board is not bright and there is less ink, the insulation board itself is not good.
3. Weld appearance.
Because there are many parts in the circuit board, if the welding is not good, the parts are easy to fall off the circuit board, which seriously affects the welding quality of the circuit board. It is very important to carefully identify and strengthen the interface.
Second: high quality circuit board proofing needs to meet the following requirements
1. After the components are installed, the telephone should be easy to use, that is, the electrical connection should meet the requirements;
2. The line width, line thickness and line distance shall meet the requirements to avoid heating, open circuit and short circuit of the line;
3. Under high temperature, the copper skin is not easy to fall off;
4. The copper surface is not easy to oxidize, which affects the installation speed. It will be damaged soon after oxidation;
5. There is no additional electromagnetic radiation;
6. There is no deformation in the shape, so as to avoid deformation of the shell and dislocation of screw holes after installation. Now they are all mechanized installation, and the error between the hole position and the design of the circuit board should be within the allowable range;
7. High temperature, high humidity and special environment resistance should also be considered;
8. The mechanical properties of the surface should meet the installation requirements;
The above is the circuit board proofing to judge the good or bad method, in the purchase from a pcb manufacturer, be sure to polish your eyes.