The holes on the circuit board are generally divided into copper holes and non-copper holes. The main function of non-copper holes is for positioning and installation. Generally, they are relatively large holes, above 0.8mm. The through hole is generally a plug-in or a via. The most common hole on the PCB should be a via (via hole). The hole diameter of the plug-in is larger than the via hole size, generally above 0.5, based on the placement of capacitors and resistors. , Sockets and other components. The via hole is mainly used for conduction. The hole diameter is generally small, and the common hole diameter is less than 0.3. With the increase of precision boards, the product function requirements increase, the number of circuit boards increases, and the hole diameter becomes smaller and smaller. The aperture is 0.1mm. Laser drilling is required. Vias must play a conductive role, and there needs to be copper inside to conduct, so the thickness, saturation, and quality of the copper naturally become the key to the later work of the circuit board. Generally speaking, the thickness of the hole copper wall of the Pcb board is required to be 10um-20um, and products with higher current requirements may require more than 25.4um. Since the hole copper is electroplated later, unlike the surface copper that comes with the raw materials, the quality of the hole copper depends on the production and processing of the later circuit board factory. The length of the plating time, the working quality of the plating line, etc. Generally, saturated copper holes are required, and it is hoped to give enough time on the plating line, otherwise it is easy to cause insufficient copper holes. In addition, the copper balls are also required to be pure and hurry, otherwise it will cause blisters. Insufficient hole copper will cause the circuit board to be interrupted or burned in the later work process.