Understanding PCB Thickness: How to Choose the Right Standard PCB Thickness
- TapRen Team
- Oct 19
- 7 min read
Abstract
PCB thickness will affect the cost, electrical performance, and mechanical reliability of the electronics. The standard PCB thickness is 1.57mm, offering a trade-off between compatibility and durability; however, thinner versions (up to 2mm) can be employed in specific applications. Thinner PCBs (under 1 mm) are applicable for tiny devices. In contrast, thicker ones (1.6mm or more) are used for high-power or heavy loads compared with thin ones. Mechanical stability, electrical performance, thickness of copper layers, and price are some considerations that should guide your choice. Prototyping and consultation with manufacturers can help establish the most suitable thickness for your application, ensuring it meets both functional and economic requirements.
What is Standard PCB Thickness?
Standard PCB thickness refers to the total thickness of a PCB, including the base material, copper layers, silkscreen, and solder mask. The most common thickness is 1.57mm, which has become the industry standard, as it represents a compromise between reliability, component strength, load, and mechanical strength. This thickness is suitable for most consumer electronics, as it's sufficient to withstand manufacturing procedures, yet thin enough for handheld devices. Typical thicknesses are 0.78mm and 2.36mm, which meet the demands of specific applications, such as compact designs or high-power systems. High-quality PCB thickness, with time, relies on the design requirements and function of the board.
Measuring Methods of PCB Thickness
The following methods usually determine the thickness of the PCB:
Micrometer or Caliper
A micrometer or digital caliper is the most straightforward measuring instrument used to test the overall thickness of a PCB. It provides high accuracy and is most commonly used during both fabrication and testing procedures.
Cross-sectional Analysis
This method involves chopping a small section of the PCB and viewing it under a microscope. It helps measure the total thickness, the thickness of individual layers, and the distribution of materials.
Automated Optical Inspection (AOI)
AOI systems utilize cameras and software to inspect the board for consistency in thickness and surface quality. They are not as precise as exact measurements, but are applied in quality control and thickness anomaly detection.
X-ray Inspection
X-ray inspection is sometimes used for multilayer PCBs where internal geometry and layer alignment need to be verified. It can provide thickness data of the inner layers
without the need to actually cut through the board.
PCB Thickness Calculator
Calculating the thickness of the PCB requires calculating the trace width as well. A tool called a trace width calculator is used for this calculation. Trace width affects the thickness and current flow within the PCB, which helps optimize the manufacturing of PCBs based on performance, current flow, signaling, and other factors.
Copper Weight and Trace Width
Copper weight is a measurement of the copper available in a layer of the PCB and is expressed in terms of ounces per square foot. Heavy copper makes the board as a whole thicker, and the trace width also influences thickness, especially in high-current applications.
Dielectric Constant and Material Selection
Selecting a proper base material with efficient electrical performance, thermal conductivity, and sensitivity is important to mitigate the effects of signal impedance and uneven propagation.
Layer Count
The total layer count in a PCB determines its thickness. Multiple layers of insulating and conducting materials embedded within the PCB impact the thickness but serve to improve electrical signaling and facilitate the maintenance of complex designs.
Solder Mask Thickness
Solid mask thickness is a coating on the PCB surface that protects against oxidation and solder bridging. It also improves strength and longevity, but slightly increases the overall thickness.
Factors Influencing PCB Thickness Choice
The choice of PCB thickness is based on factors such as cost, application, and performance. Some of these factors are explained in the following section.
Application Specifications
Thin and thick PCBs are selected based on the application. Thin PCBs are commonly used in devices such as small implants, chips, and wearable devices. Thicker PCBs, which are around 2mm+ in size, are mostly used in heavy devices that require high power.
Thin PCBs
Thin PCBs are flexible and weigh 0.2mm, making them lighter. They are ideally suited for devices that require high precision and compactness. This constraint makes them prone to mechanical damage, which can be mitigated by techniques such as high-density interconnect.
Compatibility with components
The PCB thickness should be compatible with the component's size to ensure proper functioning and maintain compactness.
Mechanical Strength
Thinner boards have lower mechanical strength compared to thicker ones.
Standard Thickness
Most standard PCBs have a thickness of 1.6 mm, which offers optimal durability, mechanical strength, and compatibility. The PCBs with standard thickness are primarily used for general-purpose devices.
Manufacturing Constraints
Most PCBs with standard thicknesses of around 1.6mm offer cost-effectiveness. In contrast, PCBs with various thicknesses, other than the standard, require precise manufacturing processes, which increases the cost and time.
How to Choose the Right PCB Thickness
Here are a few steps;
Begin with Application Requirements
Firstly, determine if the application has specific needs, such as flexibility, rigidity, and space constraints.
Examine Component Weight
The heavier-weight components require thicker PCBs to avoid bending or warping.
Analyze Thermal Requirements
High-power-consuming applications need thicker PCBs for improved heat dissipation.
Estimate Mechanical Stress
Applications that experience vibration or physical impact may require more durable, thicker PCBs.
Inspect Electrical Performance Needs
Signal integrity requirements may also influence the chosen thickness.
Check Manufacturing Capabilities
Always ensure the chosen thickness falls within standard manufacturing parameters to prevent incurring excessive costs.
Balance Cost and Performance
Standard thicknesses like 1.6mm offer cost benefits, while custom thicknesses may provide performance advantages.
Case Studies
Here are a few considerations given below;
Effect of PCB Thickness and Height Position During Heat Level Type Vapor Phase Reflow Soldering
This study investigated the effect of PCB thickness and vertical position on heat transfer in a vapor phase reflow oven during soldering. PCBs that are thin in size heat up faster and reach extreme temperatures. On the other hand, thick boards exhibit slower heating and cooling due to their greater thermal mass.
Moreover, PCBs placed in higher temperatures in the oven experience reduced heat transfer, resulting in lower temperatures. Both factors, thickness and height, significantly influence soldering quality and process optimization, resulting in the need for precise control in advanced electronics manufacturing, which is vital.
Effects of PCB Thickness on Adjustable Fountain Wave Soldering
This study investigated how PCB thickness influences the vertical fill of pin-through-holes (PTH) during soldering using adjustable fountain and conventional wave soldering methods. Three PCB thicknesses (1.6 mm, 3.1 mm, and 6.0 mm) were tested.
Results showed that thinner PCBs (1.6 mm) achieved nearly 100% vertical fill, while thicker PCBs (6.0 mm) had significantly lower fill levels (~50%). The adjustable fountain wave soldering consistently outperformed conventional wave soldering in terms of fill quality. The overall study highlights that increased PCB thickness and aspect ratio minimize solder fill efficiency and also impact joint durability.
Standard PCB Thickness of 2-layer, 4-layer, and 6-layer PCBs
PCB thickness fluctuates depending on the number of layers and design requirements. While 1.6mm is the industry standard, additional layers or high-performance applications typically require thicker boards. A brief guide for typical PCB thicknesses based on common layer counts is listed below:
PCB Layer Count | Typical Standard Thickness | Notes |
2-layer | 1.6mm | Default standard |
4-layer | 1.6mm – 2.0mm | For better EMI control |
6-layer | 1.6mm – 2.4mm+ | It depends on copper weight and signal integrity needs |
Key Takeaways
Generally, a PCB thickness of around 1.57mm to 1.6mm is considered the standard, offering a balanced solution for most consumer electronics and general-purpose applications.
PCB thickness is defined based on design needs. Thicker boards as low as 0.2mm are used in compact, flexible devices. On the other hand, thicker boards up to 3.2mm are preferred for high-power or mechanically demanding environments.
Layer count significantly affects PCB thickness. A 2-layer board generally measures 1.6 mm, while 4-layer and 6-layer PCBs may range from 1.6mm to over 2.4mm. Signal integrity, thermal conditions, and the weight of the copper determine the thickness of these boards.
Selecting the right thickness relies on factors such as mechanical strength, electrical performance, thermal criteria, component compatibility, and manufacturing resources.
Case studies of real-world applications reveal that tailoring PCB thickness can boost performance, longevity, and space efficiency across various sectors.
Selecting the right PCB thickness is not merely a technical decision; it's a strategic one that impacts thermal management, device longevity, and other factors. At Tapren, we utilize engineering precision and materials expertise. We are committed to providing boards tailored to your exact specifications, whether you require ultra-thin flex PCBs or rugged multi-layer boards optimized for high-impact industrial environments.
Collaborate with Tapren to have every layer of your PCB engineered for performance, dependability, and future expansion. Let's design smarter, stronger boards layer by layer.
FAQs
Why is 1.6mm considered the standard PCB thickness?
1.6mm grants the required trade-off between mechanical integrity, heat regulation, and manufacturability. It provides sufficient firmness for a higher number of components while also being cost-effective. This PCB thickness is also flexible, allowing for easy manufacturing processes in the global PCB market.
What are the implications of selecting the wrong PCB thickness?
Selecting the wrong PCB thickness can lead to mechanical stress on the PCB and signal integration issues. It can also lead to challenges in component assembly and loss of thermal management capacity.
How do you calculate PCB thickness for a high-frequency application?
Before choosing a PCB thickness, impedance is first calculated. Then, the thickness is calculated using the formula Z = (87/√εr) × ln(5.98h/(0.8w+t)), where h = dielectric thickness, w = trace width, and t = copper thickness.
Can the PCB thickness vary within the same board?
Yes, thickness varies within different areas of the PCB. Based on the requirements, processes such as rigid-flex construction and cavity milling allow for the PCB to be thinner in some regions and thicker in others, serving various purposes.
What are the issues in manufacturing very thin PCBs of 0.2-0.4mm?
Ultra-thin PCBs are prone to warping during soldering, exhibit increased handling susceptibility, and have reduced mechanical strength, all of which are constrained by their aspect ratio. They are also more susceptible to surface peeling and have layer-to-layer registration challenges, and manufacturing requires specialized equipment and processes.
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PCB CONNECTOR
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