Why does PCB need to do appearance inspection?

The demand of market diversification is constantly upgrading and iterating, which puts forward higher requirements for product quality. PCB board is an irreplaceable precision component of electronic products, its quality directly affects the performance of products. Therefore, in the process of PCB production, quality inspection is very important. PCB appearance detection is a very important part of quality inspection, which has high requirements on the accuracy, efficiency, speed and other aspects of detection. The internal process of PCB is complex, in addition to the core board structure laminating, drilling, wiring, also need to consider embedded components, surface coating, cleaning and etching. However, the traditional PCB detection method adopts artificial naked eye, which is easy to miss detection, slow detection speed and long time, strict requirements on environmental conditions, and not suitable for dangerous working environment.

Due to the high degree of dependence on the precision of production equipment and material properties, it is easy to have the following kinds of problems in the design and production process:1. PCB process edge design is not reasonable, resulting in the equipment cannot be mounted.2. PCB positioning hole problem, resulting in the equipment can not be accurately and firmly positioned.3. Metallization of screw holes leads to hole plugging after wave soldering.4. PCB pad problem, welding appears virtual welding, displacement, monument, or solder spot less tin.5. The bit sign or polarity mark is missing, the bit sign is reversed, the character is too large or too small, etc.6. The distance between test points and components is not standardized, and the maintainability is poor.