In this article, we’ll discuss nine common types of rigid-flex PCB stackup, ranging from simple single-layer constructions to more complex multi-layer designs.
We’ll explore the advantages and disadvantages of each type, as well as their typical applications.
By the end of this guide, you’ll have a clear understanding of the various rigid-flex PCB stackup options available, making it easier to choose the right one for your specific project needs.
What is Rigid-Flex PCB Stackup?
Rigid-Flex PCB Stackup is a type of printed circuit board that combines both rigid and flexible materials to create a single board.
This innovative design offers several benefits, including improved durability, reduced space requirements, and enhanced functionality.
Rigid-flex PCB stackup is becoming increasingly popular in the electronics industry due to its ability to provide reliable performance in a variety of applications, from aerospace to medical devices.
Understanding the basics of rigid-flex PCB stackup can help you make informed decisions about incorporating this technology into your projects.
Rigid-Flex PCB Stackup
What the Rigid-Flex PCB Stackup Includes: Unique Features
Rigid-Flex PCB Stackup includes several unique features that distinguish it from other types of printed circuit boards.
These features include a combination of rigid and flexible materials, which allows for greater design flexibility and reduced space requirements.
Additionally, rigid-flex PCB stackup typically includes plated through-holes, which provide enhanced connectivity and signal transmission.
The use of flexible materials in the design also allows for the creation of unique shapes and forms, making it ideal for applications where space is limited.
Overall, the unique features of rigid-flex PCB stackup make it a popular choice for a variety of electronic applications.
Rigid Flex PCB vs Traditional Rigid PCB
Rigid Flex PCB and traditional rigid PCB are two types of printed circuit boards that have distinct differences.
Rigid Flex PCB combines the use of both rigid and flexible materials, while traditional rigid PCB only uses rigid materials.
This design allows for greater design flexibility and reduced space requirements, making it ideal for applications where space is limited.
Additionally, rigid-flex PCB has improved durability and reliability compared to traditional rigid PCB, due to the reduced need for connectors and cables.
However, traditional rigid PCB may be more cost-effective for simpler designs or larger-scale production.
Understanding the differences between the two types of PCB can help you choose the best option for your specific project needs.
Rigid Flex PCB vs Traditional Rigid PCB
Why is Rigid-Flex PCB Stackup Important: Functionalities
The combination of rigid and flexible materials in the design provides greater design flexibility, allowing for unique shapes and configurations that may not be possible with traditional rigid PCB.
Additionally, the use of flexible materials reduces the need for connectors and cables, improving durability and reliability.
Rigid Flex PCB Stackup also provides improved signal integrity, due to the use of plated through-holes that allow for better signal transmission between layers.
This results in a reduction of electromagnetic interference (EMI), which can cause signal distortion and affect performance.
Furthermore, Rigid Flex PCB Stackup can reduce the size and weight of the overall circuit board, making it ideal for applications where space is limited.
This can be particularly important in applications such as aerospace or medical devices, where weight and space requirements are critical.
Benefits of Rigid-Flex PCB
Rigid-Flex PCB offers several benefits that make it a popular choice in the electronics industry.
This stack-up is cost-effective for handling & transport.
One of the major benefits of Rigid-Flex PCB is its cost-effectiveness in terms of handling and transport.
The combination of rigid and flexible materials in the design allows for more efficient handling and transport, as it reduces the need for additional connectors and cables.
This means that Rigid-Flex PCB is less likely to suffer damage during handling or transport, resulting in a reduction in assembly time and overall cost.
PCB Packaging
Weighing advantages of both rigid and flexible PCB.
Another major benefit of Rigid-Flex PCB is that it combines the advantages of both rigid and flexible PCBs.
The rigid part of the board provides a solid foundation for components, while the flexible part allows for greater design flexibility and reduced space requirements.
The use of flexible materials in Rigid-Flex PCB also offers several advantages. Flexible materials are more resistant to vibration and shock, making them ideal for applications that require durability and reliability.
They also offer improved thermal performance, as they can dissipate heat more efficiently than rigid materials.
This can be particularly important in applications where temperature management is critical.
Less number of electronic components
By combining both rigid and flexible materials in the design, Rigid-Flex PCB eliminates the need for additional connectors and cables, which can take up significant space and add to the overall cost of the circuit board.
This reduction in the number of components required also simplifies the assembly process, reducing assembly time and lowering the risk of errors during assembly.
Reduced Space and Weight
The reduction in size and weight also has benefits beyond just the physical aspects of the circuit board.
The smaller size and weight of Rigid-Flex PCB also make it easier to integrate into the final product, reducing the overall size and weight of the final product.
This can result in significant cost savings in terms of materials, shipping, and handling.
Lightweight Rigid-Flex PCB
High Aspect Ratio
Another important benefit of Rigid-Flex PCB is the ability to achieve a high aspect ratio, which is the ratio of the board thickness to the smallest hole diameter.
A high aspect ratio is particularly important in applications where high-density components are required, such as smartphones and other portable devices.
The use of Rigid-Flex PCB allows for the creation of small and densely packed circuit boards with high aspect ratios, which would be difficult or impossible to achieve with traditional rigid PCBs.
This is due to the flexibility of the board, which allows for the creation of smaller and more intricate designs.
High Thermal Strength
Rigid-Flex PCB provides high thermal strength due to the use of multiple layers of rigid and flexible materials in the design.
This design allows for the efficient dissipation of heat generated by the components, reducing the risk of overheating and damage.
3D Design Possibilities
Rigid-Flex PCB stackup offers the possibility of creating 3D designs, which is another significant advantage of this technology.
The combination of rigid and flexible materials allows for the creation of intricate and complex 3D shapes and designs, which would be difficult or impossible to achieve with traditional rigid PCBs.
Rigid Flex PCB 3D Design
Better electrical connection & improved reliability
The use of multiple layers of materials in Rigid-Flex PCB provides improved reliability compared to traditional rigid PCBs.
The additional layers of materials act as a cushion, reducing the stress and strain on the board during operation, and improving its overall durability.
Complete Testing Before Installation
Complete testing of the board is made possible by the flexible nature of the materials used in Rigid-Flex PCB.
The board can be bent and flexed during testing, ensuring that it can withstand the stresses and strains it will encounter during operation.
Testing the board before installation provides several benefits. It ensures that the board is functioning correctly and meets the required specifications, reducing the risk of failure and improving the reliability of the final product.
It also saves time and money by identifying and correcting any issues before the board is integrated into the product, reducing the need for costly and time-consuming repairs or replacements.
Eliminates Many Solder Joints and Wiring
Another benefit of Rigid-Flex PCB technology is that it eliminates the need for many solder joints and wiring.
This is because the flexible nature of the board allows for the integration of multiple circuits and components on a single board, reducing the need for additional wiring and connections.
Fewer Solder Joints and Connectors
The elimination of solder joints and wiring provides several benefits. Firstly, it reduces the risk of failures due to poor connections or wiring errors.
This improves the overall reliability of the circuit board and the final product.
Secondly, it reduces the overall size and weight of the final product, making it more compact and lightweight.
This is particularly important in applications where size and weight are critical, such as in portable electronics or aerospace applications.
Rigid Flex Solder Joints
Types of Rigid-Flex PCB Stackup
Rigid-Flex PCB technology offers a wide range of stackup options to meet the specific needs of various applications. Here are the types of Rigid-Flex PCB Stackup:
Combo 1: FR-4 Stiffener
This stackup type includes a rigid FR-4 layer and a flexible layer combined with a stiffener layer to add additional rigidity to the board. The FR-4 stiffener layer is bonded to the rigid layer, and the flexible layer is bonded to the other side of the stiffener layer.
With FR-4 Stiffener Stackup
Combo 2: ZIF Contacts
This stackup type includes a flexible layer with ZIF (Zero Insertion Force) contacts and a rigid layer with a matching connector. The ZIF contacts eliminate the need for soldering, making it easy to connect and disconnect the board.
With ZIF Contacts Stackup
Combo 3: PSA Adhesive
This stackup type includes a flexible layer with PSA (Pressure-Sensitive Adhesive) bonding and a rigid layer with a matching connector. The PSA adhesive provides a strong and reliable bond between the layers.
With PSA Adhesive Stackup
4 Layer Flex, 12 Layer Rigid
This stackup type includes four flexible layers and 12 rigid layers. The flexible layers are sandwiched between the rigid layers, providing a high level of stability and reliability.
4 Layer Flex, 12 Layer Rigid
4 Layer Flex, 6 Layer Rigid
Six rigid layers and four flexible layers make up this stackup type. By sandwiching the flexible layers between the rigid ones, a nice balance is achieved between flexibility and rigidity.
4 Layer Flex, 6 Layer Rigid
3 Layer Flex, 5 Layer Rigid
In this type of stackup, there are five rigid layers and three flexible layers, with the flexible layers sandwiched between the rigid ones. This arrangement provides the PCB with both flexibility and durability.
3 Layer Flex, 5 Layer Rigid
2 Layer Flex, 4 Layer Rigid
In circuit board design, a commonly used stackup type is one that includes a total of six layers, comprising two flexible layers and four rigid layers.
The beauty of this stackup configuration lies in the fact that the flexible layers are perfectly sandwiched between the rigid layers, resulting in an optimum balance between flexibility and rigidity.
2 Layer Flex, 4 Layer Rigid
1 Layer Flex, 3 Layer Rigid
This configuration offers a balance between flexibility and strength, making it ideal for applications that require a high degree of durability and reliability.
The single flexible layer allows for some degree of movement, while the rigid layers provide structural support and protection to the PCB’s components.
1 Layer Flex, 3 Layer Rigid
1 Layer Flex, 2 Layer Rigid
The single flexible layer allows for some degree of movement, while the two rigid layers provide structural support and protection to the PCB’s components.
This stackup type is commonly used in a variety of industries, including consumer electronics, automotive, and industrial automation, where cost-effectiveness and space constraints are important considerations.
1 Layer Flex, 2 Layer Rigid
Some Rigid-Flex PCB Stackup Applications
Rigid-flex PCB stackup configurations have become increasingly popular in a wide range of applications due to their flexibility, durability, and reliability.
Here are some of the applications where they are commonly used:
Digital Camera
Rigid-flex PCB stackups are used in digital cameras to provide compact and flexible circuitry that can be easily integrated into the camera’s small form factor.
Digital Camera
Military Weapon
In the military sector, rigid-flex PCB stackups are utilized in weapons to provide robust and reliable circuitry that can withstand harsh environments and extreme conditions.
Mobile Phone
Mobile phones require compact and flexible circuitry to accommodate their small form factors. Rigid-flex PCB stackups are used in mobile phones to provide flexible and reliable circuitry while minimizing the amount of space required.
Mobile Phone
Automobile
In the automotive industry, rigid-flex PCB stackups are used to provide reliable circuitry for electronic control systems, sensors, and other critical components.
They can also provide flexibility for the circuitry in applications where vibration and shock are common.
Aerospace
Aerospace applications require highly reliable and durable circuitry that can withstand the extreme temperatures and conditions of space.
Rigid-flex PCB stackups are used to provide flexible and robust circuitry for satellites, space probes, and other aerospace equipment.
Pacemaker
Rigid-flex PCB stackups are used in pacemakers to provide flexible and durable circuitry that can withstand the constant movement and stress within the human body.
Pacemaker
Consumer Appliances
Rigid-flex PCB stackups are also commonly used in a variety of consumer appliances such as dishwashers, refrigerators, and washing machines.
They can provide flexible and durable circuitry that can withstand the constant vibration and temperature changes associated with these types of appliances.
Laptop and Computer
Laptops and computers use rigid-flex PCB stackups to save space, reduce weight, and increase durability. They can also provide flexibility for the motherboard, allowing for more versatile designs.
Laptop and Computer
Final Words
In conclusion, Rigid-flex PCB stackup configurations have become increasingly popular in a wide range of applications due to their flexibility, durability, and reliability.
These stackup configurations allow for the integration of both rigid and flexible circuitry into a single PCB, providing a balance between structural support and flexibility.
Rigid-flex PCBs are commonly used in various applications such as consumer electronics, automotive, aerospace, medical devices, and military equipment.
They offer numerous benefits such as space-saving, cost-effectiveness, and increased durability.
As technology advances and devices become more complex, the demand for rigid-flex PCBs will continue to grow, making them an essential component in many modern electronic devices.
