FPC Common Production Problems and Detection Methods

FPC is flexible circuit board, flexible PCB. Compared with rigid PCB, it has many advantages, such as high wiring density, high assembly density, small size, light weight, thin, good flexibility, can increase wiring layer, increase design flexibility, can set circuit, electromagnetic shielding layer, metal core layer can be installed to meet the functions and requirements of special thermal insulation, etc., convenient installation and high reliability.

However, there are also many problems in the FPC production process. For example, insufficient number of ends caused by cutting tolerance problems, indentation caused by cutting machine and material problems, width problems caused by material slitting, and creases and warping caused by problems with packaging materials and tube shafts, oxidation problems caused by improper storage environment, etc. Once it appears, it is possible that the entire FPC cannot be used. Therefore, it must be tested.

Existing FPC defect detection methods are mostly derived from PCB detection algorithms, but due to their unique limitations, FPC defect accuracy requirements are higher, the detection template size is larger, the template imaging is easy to deform, and the internal circuit wiring accuracy of the FPC is very high. It is easy to produce line adhesion, crossover and short circuit, and the surface is easy to reflect light. The ordinary lens can hardly extract the internal and external lines of the circuit board at the same time, which increases the difficulty of detection. Therefore, the PCB defect detection method cannot be directly used for FPC.

At present, many companies use manual visual inspection to detect FPC defects. This method is costly, low in efficiency, and there is no relatively standardized quality inspection standard, which is prone to missed inspections and false inspections. There are also special FPC testing equipment, but due to the limitations of equipment price, technical support, after-sales service, etc., it is difficult to adapt to the low-cost, mass production needs of modern technology.