answer：

As the development of high speed, such as mobile phones, electronics, communication industry, at the same time also prompted the growing amount of PCB circuit board industry and the rapid growth, layer number of components for people, material, color, weight, precision, reliability and so on demand more and more high.

But because the market price competition is intense, PCB material cost is rising trend, more and more manufacturers in order to enhance the core competitiveness, to monopolize a market at a low price. Behind these very low prices, however, is to reduce material cost and the cost of the production process to achieve, but the device is usually prone to crack (crack), easy to scratch, abrasion (or), the comprehensive factors such as precision, performance is not standard, the serious influence to use in the weldability and reliability of the products, and so on.

In the face of a variety of PCB circuit boards on the market, can distinguish PCB circuit board is good or bad from two aspects; The first method is to judge from appearance to points, on the other hand is judged from the PCB itself quality specification requirements.

The method of ▼ judge of PCB circuit boards:

The first: visually distinguish the stand or fall of circuit board

In general, PCB circuit board appearance can through three aspects to analyze the judgment;

1, the size and the thickness of the standard rules.

On the standard circuit board PCB thickness is different, the size of the customer can be measured to check according to the thickness of the products and specifications.

2, light and color.

External circuit board has ink coverage, circuit board can have the effect of insulation, if the board of the color is not bright, less ink, insulation board itself is not good.

3, weld appearance.

Circuit board due to parts is more, if welding is not good, parts easy to fall off the circuit board, seriously affect the welding quality of circuit board, good appearance, identify carefully, it is very important to interface a little bit stronger.

Second: high quality PCB circuit boards need to comply with the following requirements

1, the required components installed after confidential phone works, namely the electrical connections to conform to the requirements;

2, line width of lines, thick line, the line is apart from the requirements, in order to avoid line fever, open circuit and short circuit;

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

4, copper surface is not easy oxidation, influence on the speed of installation, with broken soon after oxidation;

5, no additional electromagnetic radiation;

6, shape without deformation, in order to avoid the shell deformation after installation, screw hole misalignment. Are now mechanized installation, PCB hole location and circuit and the design of deformation error should be within the range of allowed;

7, and high temperature, high humidity and special environment should also be within the scope of the consideration;

8, the mechanical properties should conform to the requirements of the installation surface;