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What are printed circuit board thickness standards?

Monday, September 23rd, 2024

What is the Standard Thickness of a PCB?

The standard thickness of a PCB is often 1.6 mm. This has become the go-to thickness in the industry because it balances flexibility, cost, and performance for most applications. However, depending on the requirements of the design, PCB thickness can vary widely.

What are printed circuit board thickness standards?

Manufacturers offer various thicknesses to accommodate specific designs, from 0.4 mm (0.016 inches) for ultra-thin, flexible boards, up to 3.2 mm or even thicker for high-current, rugged applications. The choice of thickness largely depends on the type of application and the mechanical strength needed.

How is PCB Thickness Measured?

Measuring PCB thickness accurately is crucial for ensuring the board meets design specifications and performs optimally in its application. The thickness of a PCB refers to the total height of the board, including all its layers—copper, dielectric, and solder mask. This thickness plays a role in many factors, from electrical performance to mechanical stability, and must be precisely controlled. The tools and methods used to measure PCB thickness include:

1. Micrometers

A micrometer is the most common tool for measuring PCB thickness. It allows precise measurements down to fractions of a millimeter, making it ideal for multilayer PCBs where small deviations can affect performance. The micrometer is placed at various points across the board to ensure uniform thickness.

2. Calipers

Digital or analog calipers are also used to measure the thickness of PCBs. They are particularly useful for quickly gauging thickness across different sections of the board.

3. Cross-Sectioning

In cases where even more precision is required, manufacturers may opt to cross-section the board. This involves cutting a sample of the PCB and measuring it under a microscope to analyze each layer’s contribution to the overall thickness.

PCB thickness is typically measured in mils (1 mil = 0.001 inches) or millimeters, depending on the region and industry. Standard PCB thicknesses usually fall between 0.4 mm (0.016 inches) and 3.2 mm (0.125 inches), but custom designs may require other dimensions.

In mass production, quality control procedures are in place to ensure that the boards maintain a consistent thickness across large batches. Thickness tolerances range from ±10% to ±20%, depending on the manufacturer and materials used.

How Thick is a 2-Layer PCB Board?

A standard 2-layer PCB is typically 1.6 mm thick, but this can vary based on specific requirements. The board consists of two copper layers, one on each side of the insulating core.

Core Thickness: The thickness of the insulating material between the two copper layers is generally around 1.4 mm.

Copper Thickness: Standard copper thickness is 35 μm (1 oz copper), though this can be adjusted for higher current-carrying capacity.

For lighter applications, such as compact consumer electronics, a thinner board of 0.8 mm may be used, providing more flexibility and space-saving. Meanwhile, more robust applications may demand thicknesses exceeding 2.4 mm.

How Thick is a Standard 8-Layer PCB?

When it comes to multilayer PCBs like the 8-layer variant, thicknesses usually range from 1.4 mm to 2.4 mm, depending on the design requirements. With multiple layers of copper and insulating material stacked together, manufacturers must optimize thickness while considering electrical performance and mechanical rigidity.

Each additional layer introduces more copper and insulation, increasing the overall thickness. For high-frequency applications or boards that must handle significant current, thicker boards may be necessary to ensure signal integrity and thermal management.

How Does PCB Thickness Affect Thermal Performance?

The influence of PCB thickness on thermal performance is mainly reflected in heat dissipation efficiency and heat capacity.

The thickness of the PCB directly affects its heat dissipation efficiency. Thicker PCBs have greater heat capacity and better heat conductivity, and are able to conduct the heat generated by electronic components more effectively. This is because copper has good thermal conductivity, and the thicker copper foil layer can more quickly transfer heat from the heating element to the cooling area or external radiator, helping to improve the overall thermal management efficiency and protect sensitive components from thermal damage.

In addition, the thickness of the PCB is also closely related to its mechanical strength and stiffness. Thicker PCB boards have higher flexural stiffness and impact toughness, can withstand greater mechanical stress and vibration, and ensure the stability and reliability of electronic equipment in harsh environments. This is equally important in thermal management, as it helps to maintain the stable operation of electronic equipment in high temperature environments and prevent performance degradation or damage due to overheating.

However, it is important to note that while thicker PCBs are good for heat dissipation, in high-frequency applications, excessively thick PCBs may increase the impedance and coupling of the signal, thus affecting electrical performance.

What Factors Influence PCB Thickness?

PCB board thickness is one of the key parameters to be considered in the design process, which has a great impact on the performance and reliability of the circuit board. When choosing plate thickness, the following factors need to be considered:

1. Signal speed

The thinner the plate, the faster the signal speed, and vice versa. However, when the board thickness is less than 0.8mm, the signal will have a great loss, will produce serious signal interference, affecting the normal work of the circuit board.

2. Heat conduction

The thinner the board thickness, the worse the heat dissipation ability, easy to produce hot spots and thermal runaway phenomenon, affecting the performance and reliability of the circuit board.

3. Mechanical strength

The greater the thickness of the plate, the higher the mechanical strength, the smoother the surface of the plate, and the greater the bending strength. However, too thick a board will affect the assembly and size of the board design.

4. Number of layers

More layers mean a thicker board. A single-layer PCB may be as thin as 0.4 mm, while multilayer boards like an 8-layer PCB may reach over 2 mm.

Taking the above factors into consideration, it is usually appropriate to choose the plate thickness between 1.6mm-2.0mm.

How to Decide PCB Thickness?

According to different applications and needs, PCB board can be divided into a variety of thicknesses, commonly used board thickness is 0.8mm, 1.0mm, 1.2mm, 1.6mm, 2.0mm and so on. When selecting PCB board thickness, it is necessary to make comprehensive consideration according to specific application scenarios and design requirements. Here are a few ways to choose plate thickness:

1. Determine according to the circuit complexity and working environment

When the circuit complexity is high, multiple components need to be connected at the same time, or the circuit board needs to work in a high temperature environment, you are advised to select a thicker board thickness to effectively improve the performance and reliability of the circuit board.

2. Determine the device size and type

If the device size is small and requires precision assembly, a thinner plate thickness is recommended. For large devices, such as power switches and high-power LED lights, it is recommended to choose a thicker board thickness.

3. Determined according to design requirements and cost control

In terms of cost control, the thinner the plate thickness, the higher the corresponding plate cost will be. Therefore, the cost and performance should be considered comprehensively in the design, and the most appropriate plate thickness should be selected.

In addition, as an 18+ years experienced PCB manufacturer, we summarized a small tip for choosing PCB thickness, hope this is help for you.

The board thickness below 1.0mm is generally used for small electronic devices and mobile devices, such as smart watches, Bluetooth headsets and so on.

1.0mm-1.6mm PCB thickness is suitable for most common electronic devices, such as smart phones, tablets, digital cameras, etc.

Thickness >1.6mm is generally used for industrial control equipment, power switches and other large electronic equipment.

Advanced PCB Manufacturer – Best Technology

At Best Technology, we specialize in manufacturing high-quality PCBs tailored to meet your exact design specifications. We offer custom thickness options for single-layer, double-layer, and multilayer boards.

We understand that PCB thickness is critical to performance, whether you’re working on high-current applications or compact designs. Our team of experts can guide you through the selection process, ensuring that your boards are not only optimized for electrical performance but also for thermal and mechanical stability.

Why are PCBs 1.6mm Thick?

The 1.6mm thickness has become the standard for most PCBs. But why is this the preferred thickness? One reason is historical—it was a size that worked well for manufacturing processes when PCBs were first developed. Over time, this became the norm due to its balance between durability and flexibility.

From the perspective of process and cost, the thinner the PCB board, the higher the manufacturing cost. Because it is necessary to use higher levels of materials and more refined processes to meet the various requirements of PCB boards in the manufacturing process. At the same time, PCB boards that are too thin are also susceptible to environmental and mechanical forces and have poor stability. Therefore, under the premise of taking into account cost and stability, 1.6mm has become a more common PCB board thickness.

Secondly, from the perspective of compatibility and standardization, in the vacuum tube era, because the development and manufacturing of PCB substrates have not yet achieved industrial production, PCB board thickness is mainly determined according to the equipment housing/installation hardware or the required PCB board thickness. At that time, the 1.6mm specification gradually became the industry standard and provided compatibility and convenience for later PCB manufacturing and design.

In addition to 1.6mm, there are some other common PCB board thickness, such as 0.8mm, 1.0mm, 1.2mm, 2.0mm and so on. These thicknesses are usually selected based on specific application and design requirements.

For example, in the field of communications, the commonly used PCB board thickness is generally 0.8mm; In the field of consumer electronics, the commonly used PCB board thickness is generally 1.0mm. In addition, for some specific applications, you can also choose other non-standard thickness options, such as 0.4mm, 0.6mm, 2.4mm, etc.

How Thick is a 1.2mm PCB?

Compared to the standard 1.6mm, a 1.2mm PCB is thinner, which makes it ideal for compact designs where space is at a premium. The 1.2mm thickness reduces the overall weight of the PCB, which can be critical in devices like smartphones, wearables, and other portable gadgets.

Despite being thinner, 1.2mm PCBs can still provide good mechanical support and electrical performance, though they might not be as resistant to bending or mechanical stress as their thicker counterparts. This makes them better suited for applications that do not require heavy-duty handling or exposure to harsh environments.

1.2mm vs. 1.6mm PCB

So, how do you decide between a 1.2mm and a 1.6mm PCB? It depends on the specific needs of your project. Here are some factors to consider:

Mechanical Strength

A 1.6mm PCB is more rigid and can withstand greater mechanical stress, making it ideal for larger devices or environments where the board may face pressure or force. If your design requires a sturdy board, 1.6mm is a better option.

Compact Design

For smaller, more compact devices, a 1.2mm PCB can save valuable space and reduce the overall profile. This is especially important for handheld gadgets or portable electronics where size and weight matter.

Thermal Management

Thicker boards like the 1.6mm version have better thermal management properties, as they can dissipate heat more efficiently. If your PCB will handle high power or generate a lot of heat, the 1.6mm option may be a better fit.

Cost

While the difference in cost between 1.2mm and 1.6mm PCBs is usually minimal, thinner boards might be slightly more cost-effective, especially for large-volume production. However, always weigh this against the performance needs of your application.

Ultimately, the decision comes down to the balance between durability, size, and the operating environment of your product.

Is Thinner PCB Better?

A thinner PCB, like the 1.2mm version, can be better in certain applications, but it’s not universally superior. The key benefit is the reduced thickness, which translates to lighter and more compact products. This is why thinner PCBs are favored in modern consumer electronics where every millimeter counts.

However, thinner PCBs are less rigid, making them more prone to bending or warping under pressure. If the PCB is subjected to mechanical stress or has to endure rough handling, a 1.6mm thickness might be the safer choice.

For low-stress applications, such as small gadgets or tightly packed devices, a 1.2mm PCB can offer the perfect balance of performance and size. The goal is to match the thickness to the demands of your specific project.

What is the Tolerance of a 1.6mm PCB?

PCB manufacturers often specify tolerances to account for minor variations in thickness during production. For a 1.6mm PCB, the typical tolerance range is around ±0.10mm, though this can vary based on the manufacturer and specific requirements of the project.

Tolerances are crucial in ensuring that the PCB fits within the required mechanical constraints of the final product. When designing a product, it’s essential to account for this tolerance, especially if your design requires exact thickness dimensions.

The tolerance of a 1.6mm PCB helps ensure consistent performance, even with minor deviations in the manufacturing process.

How Thick is a Standard 2-Layer PCB?

A standard 2-layer PCB typically ranges from 1.6mm to 2.4mm in thickness. However, 1.6mm is the most common thickness for 2-layer boards used in a wide range of applications.

The two layers refer to the copper traces that are used for electrical connections, and the thickness of the board itself determines its strength, thermal properties, and overall performance. In most cases, a 1.6mm thickness offers an ideal balance for general use, providing both durability and flexibility in terms of design and assembly.

How to Choose a Suitable PCB Thickness?

When choosing the thickness of a PCB, several factors need to be considered:

1. Weight

Weight is a key factor. Thinner boards tend to be more fragile and are more likely to break. Therefore, if lightweight is not a strict requirement, thicker boards are usually the better choice.

2. Flexibility

Flexibility is another important consideration. Thinner boards are generally more flexible, but they are also more prone to breaking. Thicker boards offer less flexibility but provide greater stability.

3. Space

The amount of space available in your device is crucial when deciding on PCB thickness. If your device has enough room to accommodate a thicker PCB, then using a thicker board is advisable. On the other hand, if the device is compact, a thinner PCB may be necessary to fit into the available space.

4. Type of Connectors and Components

The type of connectors and components you plan to use also influences the PCB thickness. Different components may have specific requirements that determine the board’s thickness.

5. Dimensions and Design

When selecting PCB thickness, factors such as the dimensions of the PCB, the number of layers, the weight of the installed components, the installation method, and impedance should all be considered. A general rule of thumb is: when the aspect ratio of the PCB (length to width) is not greater than 2 and the width-to-thickness ratio is not greater than 150, the performance is optimal. The width here refers to the smaller dimension between the depth or height of the PCB.

For plug-in boards mounted in vertical boxes, the thickness should fully consider deformation issues. For PCBs that are not box-mounted, if the size is smaller than 300mm x 250mm, 1.6mm to 2mm thick boards are preferred. Larger PCBs should use 2mm, 2.4mm, 3mm, 3.2mm, 3.5mm, or even thicker boards, but it is best to avoid exceeding 4mm.

6. Copper Thickness, Layers, and Signal Type

When determining the PCB thickness, you should also factor in the copper thickness, the material of the board, the number of PCB layers, the types of signals it will carry, and the type of through-holes being used. The operating environment is another key consideration.

PCB Manufacturing Considerations

Several manufacturing factors also influence the final PCB thickness:

Drilling equipment capability

Copper thickness

Number of layers

Board cutting method

For non-standard thickness PCB designs, additional factors include:

1. Manufacturer Capability

The first consideration is whether your PCB manufacturer has the equipment and capability to produce the specific thickness you need. This decision should be made early in the design process, along with other Design for Manufacturing (DFM) requirements. Otherwise, you may need to make changes and redesign your PCB stack-up.

2. Extended Delivery Time

If your manufacturer does not stock the materials required for non-standard thickness, it could delay the production timeline. Therefore, it’s essential to consider the delivery time when choosing a non-standard thickness.

3. Additional Costs

This is perhaps the most important point: you need to evaluate the cost of special materials, additional manufacturing costs, and the potential impact of delayed delivery to determine if the extra expenses are justifiable.

Opting for standard PCB thicknesses typically results in faster production and lower costs. However, if you decide on a non-standard thickness, it’s crucial to communicate with your manufacturer early in the design phase. This ensures that they can meet your requirements, and you’ll also need to clarify lead times and any additional manufacturing costs.