Introduction
Standard PCB thickness is a critical factor in electronic design and manufacturing, influencing component compatibility, mechanical durability, heat dissipation, manufacturing processes, and electrical characteristics. PCBs are typically available in standard thicknesses like 1.6mm and 0.8mm, chosen to ensure that electronic components fit properly, maintain structural integrity, dissipate heat efficiently, facilitate manufacturing, and meet desired electrical properties.
This standardization is essential for the reliable and cost-effective production of electronic devices across various industries. Standard PCB thicknesses vary to meet the diverse needs of electronic design and manufacturing.
Common choices include 1.6mm (approximately 0.063 inches), which offers a balance of mechanical strength and component compatibility.
And 0.8mm (approximately 0.031 inches), which is preferred for applications with space constraints.
Thinner options like 0.6mm (approximately 0.024 inches) or 0.4mm (approximately 0.016 inches) are suitable for lightweight, compact devices.
While thicker PCBs like 2.0mm (approximately 0.079 inches) excel at dissipating heat in high-power applications.
The availability of these standard thicknesses caters to a wide range of electronic needs, ensuring the versatility and adaptability of PCBs across industries.
Selecting the right PCB thickness is paramount for electronic devices, as it directly impacts their performance, reliability, and manufacturability. The chosen thickness influences the mechanical integrity of the device, ensuring it can withstand physical stresses and maintain structural stability. It also affects heat dissipation, which is crucial for preventing component overheating and ensuring prolonged operation.
Furthermore, PCB thickness plays a pivotal role in accommodating various electronic components, preventing height mismatches and interference. Electrical characteristics like impedance and signal integrity are influenced as well, impacting the device’s functionality. Finally, adhering to standard PCB thicknesses facilitates cost-effective manufacturing processes, making it vital to make informed decisions about thickness to meet the specific requirements of the intended application and optimize the overall performance of electronic devices.
Common standard PCB thickness options
Standard PCB thickness options serve as a foundation for electronic design, allowing engineers to tailor their choices to specific project requirements. By understanding the unique characteristics of each thickness, designers can make informed decisions that ensure compatibility, durability, and cost-efficiency in electronic manufacturing while aligning with the constraints and objectives of their projects.
1.6mm (0.063 inches)
The 1.6mm PCB thickness is the most prevalent choice in electronic design due to its versatility. It strikes a balance between mechanical stability and component compatibility, making it suitable for a wide range of applications. This thickness offers ample rigidity, preventing the bending or warping of the board during handling and assembly. It accommodates various electronic components, including ICs, connectors, and passive components, making it a go-to option for both consumer and industrial electronics. Its widespread availability also contributes to its popularity, ensuring cost-effective manufacturing processes.
0.8mm (0.031 inches)
The 0.8mm PCB thickness is preferred in applications where space constraints are critical. It is thinner and lighter compared to the 1.6mm option, making it ideal for compact and portable devices such as smartphones, tablets, and wearables. Its reduced weight can be a significant advantage in applications where weight savings are essential, such as drones or aerospace systems. However, designers must be mindful of its decreased mechanical rigidity and plan for additional support or reinforcement if necessary.
1.0mm (0.039 inches)
1.0mm PCB thickness is less common but still available for specific design needs. It provides a compromise between the mechanical stability of 1.6-mm boards and the space-saving advantages of 0.8-mm boards. This thickness offers moderate flexibility while maintaining some level of mechanical robustness, making it suitable for devices that require both compactness and durability. Designers might opt for 1.0mm thickness when seeking a middle ground between the other two standard options, although availability and manufacturing considerations may vary.
Factors to consider when choosing PCB thickness
The impact of PCB (printed circuit board) thickness on the overall performance and functionality of an electronic device is substantial and multifaceted.
Mechanical Integrity
PCB thickness affects the mechanical durability of the device. Thicker PCBs provide greater rigidity and resistance to bending or warping, ensuring the device can withstand physical stresses, vibration, and mechanical shocks. This is especially crucial in applications subject to harsh environmental conditions.
Component Compatibility
The thickness of the PCB must match the height requirements of electronic components like integrated circuits (ICs), connectors, and heatsinks. Selecting the wrong thickness can lead to issues like components not fitting properly or protruding beyond the intended enclosure, causing assembly and functionality problems.
Electrical Characteristics
PCB thickness affects electrical characteristics, including impedance and signal integrity. The thickness has an impact on the trace widths, spacing, and dielectric properties, which can affect the electrical performance of the circuit. Designers must select a thickness that aligns with the desired electrical properties of the device.
Weight and Size
Thicker PCBs are heavier and can increase the overall weight of the device, which may be a concern in applications where weight is a critical factor, such as aerospace or portable electronics. Thinner PCBs are preferred when minimizing the device’s size and weight is essential.
Thermal management considerations
Heat Dissipation Capability
PCB thickness directly affects the board’s ability to dissipate heat. Thicker PCBs have a larger thermal mass, allowing them to absorb and distribute heat more effectively. This is advantageous in applications where heat generation is high, as it helps prevent localized overheating and ensures even heat distribution across the board.
Thermal Resistance
Thicker PCBs typically have lower thermal resistance. Thermal resistance measures how effectively a material conducts heat. A lower thermal resistance means that heat can flow more easily through the PCB, reducing the risk of components overheating. This parameter is crucial for ensuring that critical components remain within their safe operating temperature range.
Component Placement and Layout
PCB thickness impacts the placement and layout of heat-generating components. Thicker PCBs offer more space for heat sinks and heat spreaders, allowing for efficient heat dissipation from power components or processors. Designers must consider the available space and thickness constraints when determining the optimal location for components to ensure proper thermal management.
Layer Stack-up
The layer stack-up is a critical aspect of PCB design that directly affects the board’s thickness. Designers must carefully think about the number of layers, the thickness of the dielectric material, the thickness of the copper, and the use of vias to get the right electrical and mechanical properties while staying within the thickness limits set by the application and the available space. The layer stack-up configuration is an integral part of optimizing PCB design for a wide range of electronic applications.
Number of layers
The most apparent impact is the number of layers in the stack-up. PCBs can be single-layer, double-layer (also known as two-layer or 2-layer), or multilayer. Each additional layer contributes to an increase in thickness. For instance, a multilayer PCB can have several copper and dielectric layers stacked together, whereas a double-layer PCB typically consists of two copper layers separated by a core layer of dielectric material.
Dielectric Material Thickness
The core and prepreg layers in the stack-up consist of dielectric material. The thickness of these dielectric layers can vary based on the desired electrical characteristics and the manufacturer’s capabilities. Thicker dielectric layers increase the overall PCB thickness. Designers can select specific core and prepreg thicknesses to achieve the desired electrical properties and mechanical characteristics.
Copper Thickness
The thickness of the copper layers, which is typically measured in ounces (oz), contributes to the overall thickness of the PCB. Copper layers that are thicker can handle larger currents and provide better heat dissipation but at the expense of increasing the thickness of the board. Copper is often measured in thicknesses of 1 ounce, which corresponds to around 1.4 mils (or 0.035 mm), and 2 ounces, which measures approximately 2.8 mils (or 0.071 mm).
| Layer Stack-up | Layer | Thickness |
| Top Mask | 0.01 | |
| Top Copper | 0.035 | |
| Dielectric | 1.5 | |
| Bottom Copper | 0.035 | |
| Bottom Paste | 0.01 |
Layer Stack-up 2 Layers 1.6mm Thickness 1Oz Copper
Layer Stackup Design
The particular arrangement of the copper layers and dielectric materials that make up the stack-up affects the overall thickness. PCB designers have the flexibility to determine the layer order, core thickness, and prepreg thickness of the board in order to suit the design’s electrical and mechanical requirements. In order to obtain the necessary impedance, signal integrity, and mechanical qualities while simultaneously balancing the thickness limits, the layer stackup is customized.
Manufacturability
PCB fabrication processes, such as etching, drilling, and soldering, are optimized for specific thicknesses. Choosing non-standard thicknesses can complicate the manufacturing process, increase costs, and lead to production challenges.
PCB thickness is a crucial design parameter that impacts the mechanical, thermal, electrical, and manufacturability aspects of electronic devices. Careful consideration of the specific requirements of the application is essential when selecting the right PCB thickness to ensure optimal performance, reliability, and functionality of the device.
The following manufacturing processes are to be kept in mind and finalized before the selection of PCB thickness.
Depanelizing Methods
Manufacturers make PCBs in large panels containing numerous boards, which are subsequently divided into individual boards. The thickness of the board influences which depanelization processes can be used. Thicker boards may require careful scoring and depanelization, while thinner boards may be routed to generate breakaway tabs. Before PCB manufacturing can begin, depanelization procedures and specifications must be carefully established.
Drill Hole Equipment
While drill hole size and spacing are frequently emphasized for performance objectives, drill hole production procedures include some complexity that cannot be overlooked. Fabricators are limited when drilling any form of drill hole by the thickness of the board as well as the diameter and depth capabilities of milling machines and lasers.
An aspect ratio, which is the proportion of the drill hole’s diameter to depth, serves as a signal for this restriction. All manufacturers should strive for a 7:1 aspect ratio when drilling standard holes. Some manufacturers can achieve a higher aspect ratio; however, this must be specified prior to finalizing the board design and usually comes at an additional expense. This means that small-diameter holes are less likely to be fabricated on thicker boards.
Mechanical stability and durability
PCB thickness is intricately connected to its mechanical stability and endurance, which are critical considerations in the design of electrical devices. Thicker printed circuit boards (PCBs) provide enhanced rigidity, rendering them more proficient in scenarios where preserving structural integrity and withstanding bending or flexing are of utmost importance. This is particularly evident in the context of large-scale industrial systems. Additionally, these materials possess enhanced impact resistance properties, thereby reducing the potential for damage resulting from physical shocks or handling stressors. As a result, they are particularly well-suited for use in demanding or harsh situations. Nevertheless, the increased weight of these objects requires meticulous attention to the process of mounting and fastening. Moreover, PCBs with increased thickness exhibit improved resilience against thermal expansion and contraction, rendering them well-suited for use in scenarios characterized by significant temperature variations. Furthermore, these thicker PCBs have the ability to enhance resistance to moisture penetration when appropriately sealed and coated. However, designers are required to strike a delicate balance between these aforementioned benefits and the limitations imposed by weight restrictions. This is necessary in order to fulfill precise mechanical criteria, thereby ensuring the overall dependability and durability of the electronic apparatus.
Cost Considerations
The analysis of costs is a pivotal factor in establishing the most advantageous thickness of a printed circuit board (PCB) for the purpose of electrical gadget design. Thicker printed circuit boards (PCBs) are often linked to elevated manufacturing costs due to many contributing variables. These factors encompass the utilization of increased quantities of resources, the requirement for supplementary processing stages such as drilling and plating, and the potential for extended production durations. As a result, designers who place a great deal of importance on economic factors often opt for the use of thinner printed circuit boards (PCBs) as a means of reducing manufacturing costs. However, it is crucial to attain a balanced equilibrium between cost reduction and meeting the requirements of the application. In scenarios where mechanical stability, heat dissipation, or component compatibility are the major factors to be taken into account, it may be crucial to commit resources towards the acquisition of a thicker printed circuit board (PCB), regardless of the associated budgetary repercussions. In contrast, within the consumer electronics industry, where cost considerations are paramount and maintaining price competitiveness is crucial, the adoption of thinner printed circuit boards (PCBs) can offer a feasible and economically advantageous strategy. This technique enables the satisfaction of crucial functional requirements and geographical constraints.
| Material | Dielectric Constant (Dk) | Dielectric Loss (Df) | Thermal Properties | Cost |
| FR-4 | 4.3 – 4.5 | Moderate | Good thermal stability | Economical |
| FR-1 and FR-2 | Similar to FR-4 | Similar to FR-4 | Lower thermal stability | More affordable than FR-4 |
| Rogers 4000 Series | Lower Dk values available | Low | Excellent thermal stability | Higher cost compared to FR-4 |
| Polyimide (PI) | Moderate to low | Low | Exceptional thermal resistance | More expensive than FR-4 |
| PTFE (Teflon) | Very low | Extremely low | Excellent thermal stability | Among the most expensive |
| CEM (Composite Epoxy) | Varies | Moderate | Moderate thermal stability | Generally economical |
Comparison between different Dielectric Materials
The determination of the thickness of the printed circuit board (PCB) relies on a thorough assessment of cost-effectiveness and advantages, aligning with the project’s financial capabilities and economic objectives while ensuring the satisfaction of essential performance and reliability criteria.
Application Requirements
The application requirements have a significant impact on the choice of the appropriate printed circuit board (PCB) thickness in electrical device design. The prioritization of the application’s unique requirements, encompassing thermal, mechanical, and electrical considerations, has the utmost significance within the context of this decision-making procedure. For example, electronic systems with high power requirements or those exposed to mechanical strain necessitate the use of thicker printed circuit boards (PCBs) in order to provide strong mechanical integrity and effective heat dissipation. Boards with increased thickness possess the capacity to efficiently distribute and disperse heat, thereby guaranteeing that components function within acceptable temperature thresholds. On the other hand, certain applications that have limited space requirements, such as wearable devices or miniature Internet of Things (IoT) devices, require printed circuit boards (PCBs) with reduced thickness in order to optimize the available space for accommodating other crucial components. Furthermore, considerations such as the necessary impedance, maintenance of signal integrity, and existence of high-frequency elements exert an influence on the selection of PCB thickness in situations where accurate electrical performance is of utmost importance. Fundamentally, the alignment of the printed circuit board (PCB) thickness with the specific requirements of the application is crucial for guaranteeing the reliable and efficient operation of the electronic device inside its designated environment.
PCB Standards
The standard thickness of a printed circuit board (PCB) pertains to the range of thicknesses that are deemed acceptable according to established industry norms. The purpose of establishing these standards is to ensure that the printed circuit board (PCB) is able to achieve the required performance criteria and adhere to the prescribed quality benchmarks. The IPC-6012 and MIL-PRF-55110 are widely acknowledged as the predominant standards for determining the thickness of printed circuit boards (PCBs).
The IPC-6012 is a collection of guidelines for making and checking PCBs. The thickness of each layer depends on the number of layers and the board’s material. The thickness of a single-sided board should be between 0.010 and 0.062 inches. A four-layer board should be 0.031 to 0.093 inches thick.
The MIL-PRF-55110 rule governs the production and inspection of military PCBs. It specifies board thickness, copper usage, and hole drilling. The smallest single-sided board is 0.015 inches thick, largest is 0.125 inches. The smallest multilayer board is 0.062 inches thick, largest is 0.187 inches.
Calculating PCB Thickness for Your Application
In general, there is a straightforward procedure for determining PCB thickness and layer thickness values in your new design:
- Determine your needed layer count by taking into account net count and anticipated net density.
- Assume a copper weight of 1 oz./sq. ft. for the time being, and calculate the total thickness to be allocated to the remaining layers.
- Request a list of possible dielectrics from the producer of your preferred materials and assign layer thicknesses as needed for your design.
- Send your recommended stack-up to your fabricator for approval.
If your fabricator uses a standard set of materials, they should be able to provide you with a stack-up of alternate materials based on IPC slash sheets. Some fabricators will combine their available materials to create a custom stackup that fulfills your impedance and loss criteria; however, they will not always force you to fit a specific stackup.
PCB thickness selection for specific applications
Consumer Electronics
In the realm of consumer electronics, where the emphasis is generally placed on sleek and lightweight designs, the recommendation of utilizing thinner printed circuit boards (PCBs) is frequently observed. The use of a commonly employed thickness of 1.6mm is common due to its ability to strike a harmonious equilibrium between mechanical stability and cost-effectiveness. Thinner alternatives, such as 1.0mm or even 0.8mm, are also viable for smartphones, tablets, and laptops, where spatial limitations are of utmost importance. Thinner boards are utilized to optimise the internal capacity for components, batteries, and user interfaces, thus satisfying the requirements of contemporary consumer electronics.
The selection of PCB thickness holds considerable significance within the smartphone sector, where emphasis is placed on sleek and lightweight designs. For example, corporations such as Apple have constantly pursued the objective of producing increasingly slender smartphones with each successive generation of the iPhone. The iPhone 6, as an illustration, incorporated a smaller printed circuit board (PCB), hence enhancing the device’s aesthetically pleasing design. Nevertheless, this methodology encountered obstacles when certain users raised concerns over bending problems. In future iterations, Apple made adjustments to the thickness of the printed circuit board (PCB) in order to improve the structural integrity and mitigate the potential for bending, all while preserving the intended form factor.
Automotive
The automotive sector necessitates durable and dependable electronic systems capable of enduring demanding environments. In automotive applications, there is a prevalent preference for thicker printed circuit boards (PCBs), often measuring 1.6mm or greater in thickness. These boards offer the essential mechanical stability required to withstand vibrations, temperature variations, and challenging environmental conditions. Increased thickness of printed circuit boards (PCBs) also plays a significant role in enhancing heat dissipation, which is of utmost importance for vehicle electronics that could potentially encounter elevated temperature environments. Reliability holds paramount significance in safety-critical systems such as engine control units (ECUs) and airbag systems, and the utilization of thicker printed circuit boards (PCBs) contributes to this objective.
Reliability holds utmost significance in the realm of automotive applications. Engine control units (ECUs) responsible for crucial tasks such as fuel injection and emissions control exhibit a preference for thicker printed circuit boards (PCBs). Boards with increased thickness provide enhanced mechanical stability and resilience to temperature variations and vibrations. As an illustration, Bosch, a prominent provider of automotive electronics, employs thicker printed circuit boards (PCBs) in its electronic control units (ECUs) to effectively address the stringent requirements of the automotive sector, thereby guaranteeing sustained dependability and safety.
Aerospace and Defence
The aerospace and defense sectors need the highest levels of reliability and durability. It is advisable to use thicker printed circuit boards (PCBs), often measuring 2.0mm or greater, in order to effectively endure substantial fluctuations in temperature, mechanical strains, and demanding performance criteria. The boards have been specifically engineered to function effectively in challenging conditions, such as settings characterized by elevated altitudes, radiation exposure, and severe temperature variations. The increased thickness of the material enhances its mechanical stability, making it more resistant to vibrations and facilitating efficient heat dissipation.
The aerospace sector heavily depends on resilient avionics systems that function under very demanding circumstances. The avionics systems of the Boeing 787 Dreamliner are equipped with printed circuit boards (PCBs) that possess increased thickness in order to endure the challenging conditions associated with high altitudes, temperature fluctuations, and electromagnetic disturbances. The printed circuit boards (PCBs) in question have been specifically engineered to possess outstanding levels of durability and dependability, particularly in the context of aircraft applications. This is of utmost importance due to the potentially disastrous ramifications associated with electrical malfunctions in such scenarios.
Industrial Electronics
The field of industrial electronics has a diverse array of applications, spanning from the automation of manufacturing processes to the implementation of control systems. The selection of printed circuit board (PCB) thickness is contingent upon particular environmental factors and spatial limitations. In industrial settings where reliability is of utmost importance, it is normal to use thicker boards, typically measuring 1.6mm. However, in conditions that do not impose stringent demands, thinner alternatives may be deemed appropriate. The selection frequently depends on variables such as the range of temperature, levels of vibration, and anticipated lifespan.
The optimal performance of industrial automation controllers necessitates achieving a delicate equilibrium between compactness and durability. Siemens, a prominent industrial automation corporation, employs diverse printed circuit board (PCB) thicknesses within its Simatic S7-1200 programmable logic controller (PLC) line. Thicker printed circuit boards (PCBs) are used in the central processing unit (CPU) core modules to boost their longevity. Conversely, thinner PCBs are employed in extension modules to optimize space utilisation within control cabinets.
Medical Devices
Medical devices often require compact yet reliable PCBs. Thinner PCBs, like 1.0mm or 0.8mm, are typically preferred for portable medical devices and wearables. However, medical equipment used in hospitals or clinics may benefit from a standard 1.6mm thickness to ensure robustness and longevity.
The use of wearable health monitors has become increasingly prevalent within the medical equipment business. Thinner printed circuit boards (PCBs) are frequently preferred for such gadgets in order to enhance both comfort and portability. As an illustration, Fitbit’s wearable devices include smaller printed circuit boards (PCBs) in order to preserve a slender physical form while offering essential health monitoring capabilities. The printed circuit boards (PCBs) have been specifically engineered to possess a lightweight and low-profile design, with the aim of optimizing the overall user experience.
Conclusion
In summary, the choice of printed circuit board (PCB) thickness holds significant importance in the realm of electronic device design, exerting influence on a wide range of industries and applications. The optimal thickness is contingent upon a nuanced equilibrium between factors such as mechanical stability, heat management, cost considerations, and space limitations. In the realm of consumer electronics, there is a prevalent inclination towards the utilization of thinner printed circuit boards (PCBs) in order to attain aesthetically pleasing and streamlined designs. Conversely, the automotive and aerospace sectors exhibit a contrasting preference for thicker PCBs, driven by their imperative need to adhere to rigorous standards of reliability and environmental durability. The selection of PCB thickness in the industrial and medical sectors is tailored to meet the specific requirements of their respective applications, taking into account elements like vibration levels and temperature ranges. The thickness of printed circuit boards (PCBs) plays a crucial role in determining the functionality, durability, and cost-efficiency of electronic devices in various industries. It ensures that these devices consistently and effectively carry out their intended functions under a range of conditions. The ability to select the most suitable thickness for printed circuit boards (PCBs) offers designers the flexibility to customize their solutions in order to address the specific issues associated with each application. This capability plays a crucial role in fostering ongoing progress and innovation within the realm of electronics.
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