What is Plated Through Hole?
Plated Through Hole, abbreviated as PTH, also known as immersion copper, holed, plated through hole. It refers to the process of hole metallization, which refers to the process in which each layer of printed circuits is electroless plating and electroplating in the hole to plate a layer of conductive metal on the insulated hole wall to make them reliably communicate with each other.
The requirements for metalized holes are strict, requiring good mechanical toughness and electrical conductivity. The metalized copper layer is uniform and complete, with a thickness between 5 and 10 μm.
The plating layer is not allowed to have serious oxidation, and there is no delamination or no Bubbles, no drill chips, no cracks, hole resistance below 1000μΩ (the 15th Institute standard is 500μΩ). The effect seen in the PCB layout is shown in Figure 1-16.
Figure 1 – Diagram of the plated through hole in the pad editor
Figure 1-1 3D diagram of PTH
What is Non-Plated Through Hole?
Non-Plated Through Hole, abbreviated as NPTH, is just to drill a hole in the post process of the finished board, and it is used for mechanical positioning. This hole is the same as the metalized hole. It can also have drill holes and pads, but the inner wall of the via hole is free of copper. All are called non-metalized holes.
The biggest difference between metalized holes and non-metalized holes is whether there is copper on the inner wall of the via. The effect of the non-metalized holes seen in the PCB layout is shown in Figure 2. The most significant feature is the non-metalized holes. The hole size is the same size as the pad.
Figure 2 – Diagram of non-plated through holes in the pad editor
Figure 2-1 3D diagram of NPTH
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