However, due to the fierce market price competition, the cost of PCB board material is also in the rising trend, and more and more manufacturers monopolize the market with low price in order to enhance the core competitiveness. However, behind these ultra-low prices, is to reduce the cost of materials and process manufacturing costs to obtain, but the device is usually prone to cracks (cracks), scratches, (or abrasions), its precision, performance and other comprehensive factors are not up to the standard, seriously affect the use of the product in the weldability and reliability. The rapid development of mobile phone, electronics, communication industry and other industries also promotes the continuous growth and rapid growth of PCB industry. People have higher and higher requirements on the layer number, weight, precision, material, color and reliability of components.
First: distinguish the appearance of the circuit board is good or bad (generally, the appearance of the PCB circuit board can be analyzed and judged from three aspects;

1. Standard rules for size and thickness.
PCB thickness of standard PCB is different size, customers can measure and check according to their own product thickness and specifications.

2. Light and color.
The external circuit board is covered with ink, the circuit board can play an insulating role, if the color of the board is not bright, less ink, the insulation board itself is not good.

3. Appearance of welding seam.
Circuit board due to many parts, if the welding is not good, parts easy to fall off the circuit board, seriously affect the quality of the circuit board welding, appearance is good, carefully identify, strong interface is very important.

Second: high-quality PCB circuit board needs to meet the following requirements

1. The telephone machine shall be easy to use after the components are installed, that is, the electrical connection shall meet the requirements;

2. The line width, line thickness and line spacing of the line shall meet the requirements to avoid heating, circuit breaking and short circuit of the line;

3, high temperature copper is not easy to fall off;

4, copper surface is not easy to oxidation, affect the speed of installation, oxidation after use soon after broken;

5. No additional electromagnetic radiation;

6. The shape is not deformed to avoid deformation of the shell and dislocation of screw holes after installation. Now it is mechanized installation, the hole position of circuit board and deformation error of circuit and design should be within the allowable range;

7. High temperature, high humidity and special environmental resistance should also be considered;

8. The mechanical properties of the surface shall meet the installation requirements;