Common three kinds of PCB drilling, rounding

Common three kinds of PCB drilling, we first introduce the PCB in common drilling, hole, blind hole, hole. The meaning and characteristics of these three holes. The guide hole ( VIA） , this is a common hole is used for conducting or connect the circuit between conductive graphics in different layers of copper foil. For instance, Such as blind, buried holes) But not instrumentation component lead leg or other reinforced material of copper plated holes. Because the PCB is composed of many copper foil layer stacked accumulated and formed, each layer will be covered with a layer of insulation layer between copper foil, copper foil layer can't exchange between each other, so the signals of links is by conduction hole ( via） , so there will be a Chinese guide hole. Features are: in order to meet customer demand, circuit board guide hole must be the fortress hole, so the change of traditional aluminum plug hole process, complete the PCB board face with white net resistance welding and plug hole, make its steady production, reliable quality, more perfect. Guide hole is mainly have the effect of circuit connected conductivity, with the rapid development of electronic industry, also for printed circuit board production process and surface-mount technology put forward higher requirements. Guide the process of making plug hole hole gave birth to the application, at the same time, should meet the following requirements: 1. Guide hole with copper, resistance welding can plug will not plug. 2. Conducting hole must be tin lead, has the certain thickness requirements ( 4um） Can not have solder resist ink into the hole, hole with Tibetan beads. 3. Guide hole must have solder resist ink plug hole, not pervious to light, can not have tin, tin beads and level requirements. Blind holes: is the outermost layer of PCB circuit to connect with the adjacent inner to plating holes, because can't see opposite, so called blind. At the same time in order to increase the space utilization of the PCB circuit layers, blind hole is on the application. Namely to a printed circuit board on the surface of the guide hole. Features: blind hole located at the top of the circuit board and the underlying surface, have a certain depth, used for surface lines and lines of the inner links below, the depth of the hole is usually no more than a certain ratio ( The aperture) 。 This way of production would need to pay special attention to the depth of the hole ( The Z axis) To the right, do not pay attention to words will cause difficult hole plating so almost no factory used, can also be connected in advance to the layer in the individual circuit when the circuit was first drill hole, and then sticking up, but need more precision positioning and contrapuntal device. Buried hole, is the internal link between arbitrary circuit layer PCB but not conduction to the outer layer, also is not extended to the guide hole on the surface of the circuit board. Features: in this process cannot be used after sticking of drilling must perform when I was in the individual circuit layer drilling, first after the local bonding lining is the first plating processing, can all the bonding, than the original guide hole and blind holes to be more time-consuming, so the price is also the most expensive. This process is usually only used in high density circuit board, to increase the other circuit layer can use the space in the PCB production process, drilling is very important, should not be careless. Because drilling is on copper clad needed to drill a hole, used to provide electrical connections, fixed function of the device. If improper operation, via the process problems, and the device cannot be fixed on the circuit board, light effect use, or the whole board to scrap, so the drilling process is very important.