1. Before entering the warehouse, IQC must conduct spot checks on the copper clad board to check if there are any scratches or exposed substrate on the board surface. If there are any, the supplier should be contacted in a timely manner and appropriate measures should be taken based on the actual situation.

　　2. The copper clad plate was scratched during the cutting process, mainly due to the presence of hard and sharp objects on the cutting machine table. During the cutting process, the copper foil was scratched and the substrate was exposed due to friction between the copper clad plate and the sharp objects. Therefore, before cutting, the table must be carefully cleaned to ensure that the table is smooth and free of hard and sharp objects.

　　3. The copper clad plate was scratched by the drill bit during drilling, mainly due to the wear of the spindle clamp or the uncleaned debris inside the clamp. The PCB sampling grab drill bit cannot grip firmly, and the drill bit does not reach the top, which is slightly longer than the set drill bit length. The lifting height during drilling is not enough, and the drill bit tip scratches the copper foil and forms an exposed substrate phenomenon when the machine tool is moving.

　　a. The clamp can be replaced by recording the number of times it is grabbed or based on the degree of wear of the clamp;

　　b. Regularly clean the clamp according to the operating procedures to ensure that there are no debris inside the clamp.