What Does PCB Aspect Ratio Mean ?

Most PCB fabricators usually publish the production capability of their PCB aspect ratio. There are some that even go an extra mile to publish their highest aspect ratio for each hole type. This is very important for HDI (high density interconnect) boards. However, how do you know that your specific design will meet the manufacturer’s capability of the PCB aspect ratio?

In this article, we will be answering this question by explaining what PCB aspect ratio is and its importance. Also, we will explain how to verify this aspect ratio, how to eliminate uncertainties surrounding PCB aspect ratios, and more. Please read on.

What Does PCB Aspect Ratio Mean and What is its Significance?

Aspect ratio can be defined as the ratio between the hole diameter and the material’s thickness through which it pierces through.

Particularly, aspect ratios are important in making sure that they achieve reliable plating process. When the PCB aspect ratios are smaller, then there is a higher probability that the copper plating stays consistent all through the hole’s length.

Higher aspect ratios or when the ratio increases than the highest possible which a fabricator can support may lead to insufficient hole plating. This leads to broken nets when it has to do with a via hole, and assembly failure when it has to do with a plated thru hole.

Usually, PCB fabricators publish some maximum aspect ratios that are manufacturable, which can serve multiple processes like microvias and through small holes. Also, each fabricator can publish different sets. Now, with this uncertainty, ensure you verify your design can suit the capabilities of the manufacturer generally, most especially their aspect ratio.

How do you Verify PCB Aspect Ratios?

Most of the time, the manufacturer checks the Printed circuit board aspect ratio. This is included with the entire DFM process. However, there is a challenge. The manufacturer, as well as the designer, is missing some important information.

While it is possible to obtain the diameter of the hole from your design data, the material (both dielectric and copper) and board thickness isn’t in the Gerber data. This is because you didn’t include them in the format. Also, most times, they are given either in drawing form or in documentation. Therefore, to verify PCB aspect ratios properly, you must communicate these values to your manufacturer. Sadly, this process is a manual one and it can easily have errors.

Also, as a designer, you may be ignorant of that specific aspect ratio that suits your manufacturer’s capabilities. This uncertainty may lead to an additional, as well as resource-consuming, spins in the design. Can you find a way to avoid all these?

Eliminating PCB Aspect Ratio Uncertainty: The PCBflow Solution

With PCBflow, you can easily get rid of any aspect-ratio uncertainty. If you run a DFM check against the capabilities of your manufacturer, then it is possible for you to believe that the values of the PCB Aspect ratio can be set correctly. Also, when the PCB fabrication and design is uploaded in the format ODB++Design to your manufacturer, the values of the thickness will be in the file for the buried and blind vias as well as through holes.

Although the PCB Aspect Ratios plays a significant role, it is just one out of all the many constraints that the PCBflow reviews. The PCB flow functions in a secure environment; therefore you can be very sure that there is full protection.

How do you Calculate PCB Aspect Ratio?

Calculating the aspect ratio in PCB vias is very important. This depends on if you are using a movie, creative venture, or a picture. The specification of this calculator is usually by statistics. This is the ratio that determines how high your graphic objects, picture, or film should go and the number of acres they must be in broadness.

Although different aspect ratios come in height and length dimensions, most times there is a reduction in its value to the lowest ratio that is acceptable and suits all media correctly.

The Sweet Numbers that a PCB Aspect Ratio Can Have

As mentioned earlier, this ratio is very important. This is due to its huge effect on plating, which is within a vias, which the annular rings affect as well.

Take for instance, your board thickness has a value of 0.2”, while the drilling diameter has a value of 0.02”. This means that it has an aspect ratio value of 10:1. When this ratio value increases, there will be more plating surrounding the vias. This contrasts the drilled hole portion, which makes it face a higher risk of having cracks as a result of the z-axis suspension during soldering.

Ensue that the microvia aspect ratio is lower. This is to ensure consistent plating all through the via, thereby greater strength for the PCB.

Majority of manufacturing shops can achieve a 6:1 PCB aspect ratio. With the least drilling diameter that floats around 0.013”, which leaves you with a maximum board that has a thickness size of about 0.078”.

Taking note of both the least drill diameter and the thickness of the board when you consider a reduced aspect ratio could save you a serious headache when manufacturing. In addition, you will have a much stronger vias, which leaves you with a higher connection which you can mount the components onto.

Making use of great software such as the Altium Designer, may assist you in knowing the right via strategies, aspect ratios, and annular rings alike.

Can Blind Vias Have an Effect on PCB Aspect Ratios?

It is possible to reduce the PCB aspect ratio using blind vias. This ratio is very important when you are making use of surface mount components like ball grid arrays.

These components usually have various pitch sizes. You can determine the aspect ratio of a printed circuit board using the ratio of the thickness of the board to the blind via’s diameter.

Making use of standard vias setting instead of the through-hole vias, as well as reducing the layer count plays a role in reducing the aspect ratio of the circuit board.


Here is the end of our article and we hope you understand what PCB aspect ratio is. You can drop your questions below, if any. You can also go through other recent articles.

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