Factors Impacting PCB Thickness

When it comes to dimensions for manufacturing applications, it’s important to understand and comply with standards. This is particularly true in the case of circuit boards. While there is no official PCB thickness standard, manufacturers recognize and widely use some widths. To simplify design, efficiently utilize manufacturing equipment, and reduce costs, these ideal thicknesses are strongly suggested. PCB thickness, on the other hand, can vary, and many designers may choose to change it for specific design and production purposes.

All You Need to Know About PCB Trace Width Calculation

Mal Fletcher

Wondering how thick PCB should be? Continue reading to know more!

How Thick PCB Should Be?

With a 10% tolerance, MCL’s standard base thickness is 0.062 inches or 1/16 inch. This is a typical PCB thickness that is also known as the industry standard. The reason for this is that in the initial days of PCB production, Bakelite sheets were just 1/16 inch thick. While this is the most common thickness, you can also find other typical thicknesses in PCB fabrication.

0.031-inch and 0.093-inch boards, in addition to 0.062-inch boards, are frequently used to suit the requirements of more durable or multi-layered boards. Other thicknesses, both within and outside of this range, may be found on boards, but these are the most prevalent.

Factors That Impact PCB Thickness:

While recognizing industry standard thicknesses is important, numerous reasons may require a custom board. Your board may have to be a non-standard thickness based on the design and manufacturing conditions. PCB thickness is influenced by two categories of factors: design and manufacturing. This article will go over each of these elements in great detail and will assist you in determining the best PCB thickness for your project.

Design Factors Impacting PCB Thickness:

These factors are mainly concerned with the board’s functionality and objective, rather than the practical decisions that need to be made during production, however, manufacturing concerns are as important. The following are some of the most critical design considerations that influence PCB thickness:

Size, Weight and Flexibility:

As compared to the thicker board, thinner boards are lighter and more flexible but they are more brittle. Therefore, they break more easily than they. While flex PCBs must be thin to be flexible, applications that do not require flexibility may benefit from a somewhat thicker board for structural reasons. While thicker boards are more durable, they also hold more weight and occupy more space inside a gadget. For lightweight applications or devices with limited spatial capacity, both of these traits may be an issue.

The Thickness of Copper:

The thickness of copper has an impact on the overall thickness of the PCB. The standard thickness of copper is 1.4 to 2.8 miles (1 to 2 ounces), however, you can change this thickness according to the board’s specific requirements. Due to material requirements and production constraints, the thicker the copper, the thicker the board, the more expensive the board is.

Materials for the Board:

The functioning and lifetime of a PCB are influenced by the materials used, but board thickness is also affected. The substrate, laminate, solder mask, and silkscreen are all common components of board production. The laminate and substrate are the most crucial components to select because they give the board’s structure and have a significant impact on overall thickness.

Depending on the required dielectric constant, the substrate can be made of paper and epoxy resin, glass weave, or ceramic. Laminates, on the other hand, are made up of layers of thermoset resin and paper or fabric. Both laminates and substrates come in a variety of alternatives that not only define a circuit board’s thermal, mechanical, and electrical qualities, but also its total thickness.

The Number of Layers On A PCB:

The thickness of the board will be influenced by the number of PCB layers. While the thickness of 2-6 layer PCBs may fall below the conventional PCB thickness barrier, the thickness of 8-layer and higher PCBs may not. While manufacturers may be able to attain standard thickness by using thinner PCB layers, this becomes extremely hard as the number of layers rises. Allow for a thicker PCB if your design requires additional layers. Reducing the number of layers is the best option if the design does not require several layers.

In addition to the design elements at play, manufacturing capabilities have a significant impact on the final PCB design. The thickness is taken into account. The following are some manufacturing considerations:

Manufacturing Factors Impacting PCB Thickness:

Drill Hole Equipment:

Drill hole size and spacing are important to designers for performance reasons, but drill hole production methods add another degree of complication. Fabricators are bound by the thickness of the board as well as the diameter and depth capacities of milling machines and lasers when drilling through holes of any kind. All manufacturers should be able to achieve a 7:1 aspect ratio for standard drilling. Some manufacturers can accomplish a higher aspect ratio, but this must be addressed with them before the board design is finalized.

The Thickness of Copper:

Etching, one of the most critical procedures in PCB production, is used to create copper traces. The thickness of the internal copper layer affects manufacturing processes such as etching and plating. As a result, thicker copper layers will have an impact on manufacturability, which could affect the design and cost of the final PCB product.

Method of Depanelization:

Depanelization is another production element to consider. PCBs are made in big panels comprising several boards, which are then separated into individual boards. The thickness of the board determines which depanelization procedures can be utilised; heavier boards may require meticulous scoring, whilst thinner boards can be routed to generate breakaway tabs.

Work closely with the manufacturer to explore depanelization methods and requirements, as well as how the PCB design might be altered to improve depanelization.

Final Thoughts

At times, it’s ideal to stick to the normal path, while at other times, it’s better to go off the beaten path. You certainly have an option when it comes to PCB thickness. Using a common PCB thickness will almost certainly result in your boards being manufactured faster and for less money. If you choose a custom thickness, make sure your CM has the precise capabilities your design may demand.

In all, when determining how thick PCB should be, ensure you are taking all the aforementioned factors into account.