1. After component installation, the phone should be easy to use, and the electrical connections should meet the requirements;

2. The line width, line thickness, and line spacing meet the requirements to avoid wire heating, open circuits, and short circuits;

3. High temperature copper is not easily detached;

4. Copper surface is not easily oxidized, which affects installation speed. After oxidation, it will quickly rupture.

5. No additional electromagnetic radiation;

6. The appearance does not deform, avoiding deformation of the shell and misalignment of screw holes after installation. Nowadays, it is all mechanized installation, and the holes, wires, and design deformation errors of the circuit board should be within the allowable range;

7. High temperature, high humidity, and special resistance should also be considered within the range;

8. The surface mechanical properties should meet the installation requirements;