The thickness of the board in PCB designing is a key factor which will influence the performance and durability of electronic devices. Technically, the standard PCB thickness refers to the default thickness of the PCB substrate. This is used in most of the applications only in the other case if any special design requirements demand another design. It is also very important to understand the PCB standard thicknesses used to enhance and optimize the performance and electrical as well as mechanical characteristics of the board. So what is the standard PCB thickness? Here is the explication of the standard PCB board thickness.
What is the Standard PCB Thickness?
The most common standard PCB thickness is around 1.6mm. This is measured around 0.063 inches and this measurement is the typical industrial standard for general-purpose PCB board. These PCB standard thicknesses are applied in most of the applications which involve consumer electronics, industrial devices and other applications.
Common Types of PCB Thickness
Standard PCB thickness 2 layer is 1.6mm. Other measurements are used in PCB designing other than the standard measurement based on the specific requirement of the design. Typically PCB thickness can range from 0.2mm to 3.2mm. The 0.2mm PCB standard thicknesses are utilized for thin and flexible PCBs to be made but on the other hand, the 3.2mm thickness is applicable for more heavy-duty boards which require high current carrying capacity. The websites of the PCB manufacturers have the standard PCB thickness charts and we can browse them online. Some of the basic standard PCB board thicknesses are given below.
- 0.8mm: This is generally used in compact devices or in applications where weight reduction is important.
- 1.0mm: This standard PCB thickness is used in handheld devices or electronics that require a moderate amount of thickness.
- 2.0mm: They are used in PCB boards which need good mechanical strength and durability to work on. They can be typically seen in the automobile and industrial sectors where heavy-duty works are held.
- 3.2mm: The general usage of PCB standard thicknesses can be seen in boards which carry and handle huge power levels. They are also utilized to provide additional durability to the board
Composition of PCB and Its Respective Impact
A PCB is generally made of multiple layers of conductive copper layer and insulating materials such as FR-4 or flame–retardant epoxy laminate etc. The final thickness of the PCB could be influenced by multiple factors.
- Copper Layer: The thickness of the copper layer is measured generally in ounces per square foot (oz/ft2). The typical value of the copper layer used will be 1oz/ft2 or 2oz/ft2. Each of the conductive copper layers adds thickness to the board. For boards that needs to carry high current or thermal loads, heavy copper layers are utilized.
- Substrate Material: FR-4, which is the core material of the PCB plays an important role in determining the overall thickness of the board. Thick core materials result in a sturdier board but also the weight will be increased for that as well.
- Prepreg Layers: Prepreg is a layer (an insulating layer) of fibreglass material which is composed of resin and they are used to bond the copper layers together. The thickness of the layers can vary depending on the design requirements.
Purpose of Standard PCB Thickness
The standard PCB thicknesses play an important role in finding the electrical, mechanical and thermal properties of the board. The primary purpose and reasons why the correct PCB standard thicknesses are essential for PCB performance are mentioned below.
- Mechanical Strength and Durability: The most obvious purpose of PCB standard thicknesses is to provide rigidity and mechanical strength to the board. When we use a thicker PCB, it will be more robust and resistant to bending and twisting or other mechanical stresses. Some applications might have harsh environments included in their operation, so they often require thicker PCBs to withstand physical stress and vibrations.
- Current Carrying Capacity: The thickness of the copper can influence the current carrying capacity of the PCB directly and therefore the usage of thicker copper traces will help in the flow of higher current without excessive heating or voltage drops. In power electronics like power supplies or motor control boards, thicker PCBs are utilized to handle higher currents and regulate thermal stability. This is one of the factors affecting the standard FR4 PCB thickness.
- Thermal Management: The thickness of the PCB is also important for dissipating heat effectively. Here, thicker boards with heavier copper layers will provide better thermal management by spreading heat more effectively all over the surface of the board. This is critical in high-power applications or devices that operate in high-temperature environments. Also, the thicker PCBs can facilitate more layers for better grounding and power distribution which helps in managing thermal issues more effectively.
- Impedance Control: In some PCBs, which are utilized in communication devices or computing systems, the operation will be at high speed and therefore, it is very hard to control the impedance of the signal traces in this case. PCB standard thickness influences the trace width and required spacing to achieve the desired impedance levels. A thicker board allows for better separation between layers which then eventually helps in reducing the chance of signal interference and improving overall signal integrity.
- Flexibility in Design: Compared to the common standard 2 layer PCB thickness, thinner PCBs like flexible or rigid-flex PCBs are often used in applications which require the board to bend or fit into tight spaces. This is achievable in smartphones, wearable devices or aerospace electronics. In all the mentioned cases, reducing the PCB standard thicknesses provides the necessary flexibility while maintaining the functionality of the circuit.
- Component Mounting and Assembly: Standard PCB board thickness also affects the components and how they are mounted as well as soldered to the board. A thicker PCB provides more support for heavy components like transformers, connectors or large capacitors. This will ensure that the solder joints are able to handle the weight without cracking or detaching. Also, the thicker boards tend to have more solid plated through-holes and they are an important and essential factor for mounting components that require mechanical stability like connectors for example.
- Signal Integrity and Crosstalk Reduction: For multilayer PCBs, The overall thickness will help to maintain the necessary separation between signal layers, power planes and ground planes. This separation is critical in preventing signal crosstalk in high-speed design PCBs. For better electromagnetic interference shielding, it is relevant to use thicker boards with additional layers which will also help to reduce the chances of signal degradation in the board.
- Cost Consideration: Thickness can directly impact the cost of manufacturing for a PCB. The thicker boards typically require more material and take longer to manufacture. Therefore, it will increase the production cost of the board. However, some applications might require mechanical strength and power handling for the board and in that case, the benefits of using a thicker PCB will outweigh the added cost for the manufacturing. However, many types of standard PCB thicknesses are used for mass production. Before we send our design to the fabrication house, we need to choose the right standard FR4 PCB thickness to get the ideal product.
Choosing the Right Thickness
What is the standard PCB thickness? This is the basic knowledge we must possess before designing a reasonable PCB. We can browse the websites of PCB manufacturers to obtain the standard PCB thickness chart and choose the right PCB thickness from it. Choosing the right PCB thickness is purely based on several factors including the applications, mechanical stress, electrical performance and cost consideration. Some guidelines are provided below to choose the appropriate thickness.
- Application Requirements: The standard PCB board thickness of 1.6 mm is sufficient enough for general-purpose electronics. Standard PCB thickness 2 layer is the most commonly used type. But for some specialized applications like medical devices, automotive electronics, aerospace systems etc., the requirement of the thickness may vary based on the environmental factors and durability required by the board.
- Multilayer PCBs: The overall thickness of the multilayer PCB must account for the number of layers on the multilayer PCB. This is because of the multiple layers of routing, power and ground planes present in the multilayer PCB. Standard PCB thickness 4 layer PCBs would be thicker according to the impedance requirement. As the number of layers increases in the PCB structure, the thickness will also increase especially in increments of 0.2 mm to 0.4 mm for all the additional layers adding up. Thicker multilayer PCBs (such as standard PCB thickness 4 layers and 6 layers) provide better EMI protection and more stable power distribution.
- Current and Power Requirements: For power distribution boards or motor controllers, the PCB must be thick enough to handle the necessary current without overheating. For this to take place, the overall board thickness must be large. Designers may also choose thicker PCBs to accommodate larger components or heavier copper to achieve better thermal performance.
- Signal and Thermal Considerations: Impedance control is a necessary factor to consider when we are building high-speed circuits. For better impedance control, the standard PCB thicknesses used have a major role in moulding the control. Thickness in this case also influences the thermal management and heat dissipation will be made efficiently for PCBs with higher thickness.
