PCB Technical - There are 3 kinds of hole styles in the PCB: Through hole, Blind hole, Buried hole

There are 3 kinds of hole styles in the PCB: Through hole, Blind hole, Buried hole

-Plating Through Hole: PTH is the most common one. You can see the bright Hole as long as you hold the PCB to the light.This is also the simplest type of hole, because it is relatively inexpensive to drill the circuit board directly with a drill or laser.However, some circuit layers do not need to connect these through-holes, which is cheaper than the through-hole, but sometimes USES more space on the PCB.

-Blind Hole: Blind Via Hole. Connect the outermost circuit of PCB to the adjacent inner layer with electroplating Hole. Because you can't see the opposite side, it is called "Blind pass".In order to increase the space utilization of PCB circuit layer, the "blind hole" process was created.This production method requires special attention to the depth of the hole (Z axis) to be just right, this method often causes difficulties in hole electroplating so almost no manufacturers use;Also may need to connect the circuit layer in advance when the individual circuit layer first drilled well the hole, finally again bonding up, but needs more precise positioning and positioning.

-Buried Hole: The connection of any circuit layer within the PCB but not connected to the outer layer.This process cannot be achieved by using the method of drilling after bonding. Drilling must be carried out at the time of individual circuit layers. After local bonding of the inner layer, electroplating must be done first, and finally all the bonding can be done.This process is usually used only on high density (HDI) circuit boards to increase the usable space of other circuit layers.