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Engineering Question 2: Plated and Non-Plated Through Holes
Posted on 29/01/2016

PCB Global’s CAM Engineering department will invariably have a few EQ’s to confirm. This is dependant on the quality of the PCB design file package received. See below example of a typical EQ for plated and non-plated through holes:

Plated (PTH) and Non-Plated (NPTH) Through Holes

EQ from CAM:

Holes noted as plated through holes do not have any pads and holes with pads are noted as non-plated through holes.

Explanation:

Generally, holes that have no pads should be non-plated through holes as without a pad landing on the top and bottom layer, the hole wall integrity can be compromised. This causes weakening as chemical solutions can seep into these areas, reducing the long term reliability of the PCB.

With the non-plated through holes with pads, although this is not uncommon, it is still a EQ that is frequently asked. These holes are best fabricated with a copper pull back from the edge of the hole (about 10mill) to ensure that there are no copper burs after drilling.

Resolution:

With confirmation from our customer both these hole types were fabricated as non-plated through holes and the non-plated through holes had the copper pulled back 10mil to ensure quality of the PCB.

For further tips and information when designing and laying out your printed circuit board design file please do not hesitate to contact our PCB Global team at sales@pcbglobal.com