PCB Aspect Ratio

PCB Aspect Ratio

There are several capabilities that are taken into account, while manufacturing a PCB Board (PCB). One such capability is the PCB aspect ratio. The ratio of the thickness of a PCB board to the diameter of the drilled hole is referred to as the PCB aspect ratio. The aspect ratio of a PCB Board plays an important role in the plating process. The ratio denotes the ability of chemical process to provide copper plated holes. As the aspect ratio goes on increasing, it becomes more and more difficult to achieve reliable plating. 

Examples

Here are some examples that illustrate the aspect ratio in a PCB Board:

--If the thickness of the PCB Board is 62 mils, and the diameter of the drilled hole is 31 mils, then the aspect ratio is 2:1.

--For an 8:1 aspect ratio, the thickness of the PCB Board is 64 mils and the diameter of the drilled hole is 8 mils.

--For an aspect ratio of 10:1, the PCB Board thickness is 80 mils, while the diameter of the drilled hole is 8 mils.

At GWT, we provide printed circuit boards (PCBs) of different aspect ratios.

PCB Aspect Ratio Capabilities Of GWT

At GWT, you can choose from different PCB thicknesses and minimum sizes of the holes. We can provide you following aspect ratio capabilities:

The aspect ratio 10:1

Why is PCB aspect ratio so important?

It is known the plated holes are divided into through-holes and blind/buried vias, which are the soul of the entire PCB layout and the panel points of different layers. In the actual plating process, the thicker the PCB thickness, the smaller the holes, the more difficult it is for the plating solution to flow through the hole, while the harder for the center areas of the holes to get uniform plated (the low current areas). 

Therefore, the higher the aspect ratio, the more difficult the plating, it often requires more advanced equipment, more expensive additives, and better manufacturing processes to achieve reliable plating. That's why when it comes to the capability of a PCB supplier, the PCB aspect ratio is always indispensable. 

What is the conventional PCB aspect ratio?

The current conventional PCB aspect ratio in the PCB industry is 8:1 (PTHs), for example:

When a thickness of 1.6mm, the min PTH is about 0.2mm,

When a thickness of 2.0mm, the min PTH is about 0.25mm.

GWT with industry-leading experiences, we now can expand the aspect ratio to 10:1 for PTHs, which means,

When a thickness of 1.6mm, the min PTH is about 0.15mm,

When a thickness of 2.0mm, the min PTH is about 0.20mm.

Meanwhile, for blind vias which are more difficult to process, we can also achieve ratio 1:1.