The holes on a circuit board are generally divided into copper holes and non copper holes. Non copper holes are mainly used for positioning and installation, and generally belong to larger holes with a diameter of 0.8mm or more. A through hole usually belongs to a plug-in or via hole, and the most common hole on a PCB board should be a via hole (conduction hole). The aperture of the plug-in hole is larger than the size of the via hole, usually above 0.5, based on the installation of capacitors, resistors, sockets, and other components. The main function of the electric hole is to conduct electricity, and the aperture is generally small, with a common aperture of less than 0.3. With the increase of precision boards, the functional requirements of the product increase, and the number of circuit board layers increases, the aperture is also getting smaller and smaller, with the minimum aperture of 0.1mm. Laser drilling is required. The through-hole needs to have a conductive effect, and there needs to be a copper sheet inside to conduct. Therefore, the thickness, saturation, and quality of the copper in the through-hole naturally become the key to the later work of the circuit board. Generally speaking, the thickness of the hole copper wall of Pcb board is required to be between 10um and 20um, and products with higher current requirements may require more than 25.4um. Due to the fact that the hole copper is electroplated in the later stage, unlike the surface copper, which comes with the raw material itself, the quality of the hole copper depends on the production and processing of the circuit board factory in the later stage. The length of electroplating time, the quality of work on the electroplating line, and so on. Generally, saturated porous copper plates are required, and it is hoped that sufficient time can be given on the electroplating line as much as possible, otherwise it may lead to insufficient pore copper. In addition, the copper ball should also be pure and fast, otherwise it may cause foaming. Insufficient copper in the holes can cause circuit boards to break or burn during later operation.