Printed circuit boards, in short, PCBs, are used across various industries worldwide. From automotive, medical, mechanical, and digital sectors to consumer goods and devices we use daily. However, not all PCBs are born the same. Different designs require different applications and scenarios. While previously we posted about multilayer PCBs, Today's article will discuss different types of Flex PCBs.

Flex PCB is used in multiple industries and applications and is significant in consumer and industrial goods. This article will cover the importance of flex PCB in the modern world and how Flex PCB is applied in different applications and use cases across multiple industries.

What is flex PCB?

Flex PCB, as its name state, is a type of flexible PCB that can be folded or bent in different directions without causing damage. The flex PCB is produced mainly from copper foil, copper materials, and other metals.

During the production process of flexible PCB, other materials are involved, such as gold, silver, aluminum, nickel, etc. The central concept that the flexible PCB is based on is good conduction flex-resistant. This means a layer that can be bent and flexed in multiple scenarios without damaging the copper material.

Multilayer flex PCB designs

Flex PCBs, similar to standard PCBs come with different layers capabilities. Flex PCB can be designed in double sides and multilayer designs to accomplish particular application needs for various industries. In today's industry, multilayer flex PCBs are often used to serve different electronic application scenarios and requirements. Applications such as high-speed data transfer and high performance and long-term functionality are most commonly used.

Unlike standard PCBs, Flex PCBs can be designed with unique, complex, and sophisticated layout designs. Due to their flexibility, better thermal control, and heat dispensing ability. Similar to standard PCBs, flex PCBs can also contain blinds, vias, and through holes, giving them more excellent flexibility benefits.

Advantages of Flex PCB

Designing an FPCs has a lot of advantages, such as the ability to be flexed and bent in different scenarios. Depending on the application, this is handy in multiple product designs and industries.

Another significant advantage is the small size that can fit in different places and shapes that standard PCB designs cannot.

For example, standard PCBs have a rigid design that can't be flexed and must be allocated in a particular order within a space.

This kind of advantage of the flexible, small size factor, and durability in different conditions and environments give the flex PCB better thermal management capabilities, which can eventually reduce the heat produced by the circuit and the way it's dissipated across the board.

A list of the most essential advantage points of flex PCB includes:

• 1. The ability to reduce wiring errors due to flexible layout design abilities.
• 2. Removing the need for mechanical connectors, which aren't normally used in flex PCB designs.
• 3. Design flexibility like no other PCB board could ever offer.
• 4. Better density support and unique layout abilities at a small form factor.
• 5. Robust temperature dispensing and thermal management capabilities.
• 6. Strong and stable signal quality.
• 7. Reduced Footprint and weight compared to traditional PCB designs.

Disadvantages of flex PCB

Although the advantages of flex PCB overcome the disadvantages, it's important to note the limitations of such a design. Flex PCB's most significant disadvantage is probably the cost, which is much higher than rigid PCBs. The increased production cost is due to the complexity and the unique material combination of the flex PCB compared to rigid PCB designs.

The second most significant disadvantage would be the logistics behind handling flex PCBs. There is a high probability of damaging the flex PCB circuit if mishandled.

Finally, the disadvantage also comes from the PCBA (PCB Assembly) process. Flex PCBs are difficult to assemble and, if done incorrectly, have a high possibility of sustaining damage without the ability to repair.

A list of the most significant disadvantages that flex PCB design comes with:

• 1. Higher cost compared to rigid PCB and different offerings of PCB designs.
• 2. Flex PCBs require specific storage conditions that other PCBs don't. Although the temperature dispensing works well, flex PCBs Can't sustain high temperatures in circuits.
• 3. Complex assembly requires special care in the PCBA process.
• 4. They are easily damaged if handled inappropriately.
• 5. Easily scratched if handled with bare hands or assembled next to non-flexible materials.
• 6. I was once broken, challenging to manually repair and requires a new flex PCBA.

To perfectly utilize the ability to fabricate and assemble a Flex PCB, we recommend using an authorized, experienced pcb assembly manufacturer. PCBasic has over 15 years of experience handling such processes in different applications and scenarios.

Whenever you design a Flex PCB or a combination of both Rigid and Flex PCBs, PCBasic high-quality PCBA manufacturer, can ensure that the advantage points will overcome the disadvantages in any case.

The flexible PCB manufacturing process

The manufacturing process of Flex PCB is not very different from rigid PCB design. The production of the flex PCB involves conductor material and polymer films in between, allowing current to flow between the layers.

Depending on the board design and the application it is used for, there will be different diameters of holes, just like traditional rigid PCB design. The holes vary in sides, but with advanced manufacturing and PCB fabrication capabilities, the holes can be as small as 25 μm. The holes support different mounting scenarios and the attachment of the flex PCB to the finished product.

Flex PCB design has a particular technique called "Filleting." Using this technique, the fabrication facility can ensure the board's integrity by reducing the stress on the pads and the termination points. By doing so, the plated through-holes in the design will ensure reliable solder joints.

The final stage in the flex PCB manufacturing process is called "button plating" this process ensures the fabrication facility will prepare the flex PCB with appropriate vias and through holes according to the original intention of the PCB designer. This process is done in rigid PCB as well.

There are different types of coating for flex PCBs, the most popular one being film polymer coating. Some of the features include:

• 1. The coating is similar to a solder mask in rigid PCBs, it will prevent circuiting traces during the PCBA soldering process.
• 2. Flex PCB protection for different types of damage (such as scratches).
• 3. Prevention of short circuits and electrification from external sources.

Coating the flex PCB is a crucial process that ensures integrity, protection, and long-life functionality of the Flex PCB design in multiple consumer and industrial applications.

Types of flexible PCBs

Not all PCBs are born the same. Flex PCBs are no different. some of the different types of flex PCB include:

• 1. a single layer (single-sided) Flex PCB.
• 2. Double-layer flex PCB.
• 3. Multilayer flex PCB.

The single-layer flex PCB is the most cost-effective, flexible, and easy to assemble, reducing the cost and risk of things going wrong. This kind of flex PCB has very high flexibility with a common concern of being over-bended and damaged in the assembly process. Those PCBs are often used to replace "wires," where flexible connectors are needed to attach multiple rigid PCBs.

Double-sided flex PCBs are an extension of the original signal layer flex PCB. This is probably the most common and popular design, offering both flexible and multi-sided features, Including the ability to put components on both sides of the flex PCB board. This type of design is easy to be manufactured in mass production. It is both lightweight, reproducible, and flexible to fit different design needs.

Multilayer PCB comes after the double-sided Flex PCBs for designs that require over two layers. This kind of design is ideal for applications that need high-density components assembly and connectors. With a multilayer PCB design, it's easy to provide a reliable solder joint during fabrication.

Importance of flex PCB in the modern world

When we talk about the importance of flex PCBs in the modern world, we want to know what industries the Flex PCBs are applied in.

Some of the industries and applications that you might find flex PCBs are:

• 1. Consumer electronics include laptops, mobile phones, calculators, cameras, printers, etc.
• 2. Manufacturing and fabrication equipment such as assembly robots, sensors, and processing and automation equipment.
• 3. Automotive vehicles such as GPS tracking systems, car computer modules, safety airbag dispensation mechanisms, and more…
• 4. Medical devices and equipment include monitoring, vitals collection devices, pacemakers, and EEG.

Flex or rigid – what design works best for me?

Different applications will have additional requirements. Before designing, it's crucial to understand the project's needs and specifications—flex PCB is best utilized in designs that require small space, density, and high flexibility.

If you are concerned whenever your design requires rigid or flex PCB design, worry no more! At PCBasic, we have professional engineers to evaluate, plan and execute Flex or wooden PCB designs according to customers' needs.

Do not hesitate to contact PCBasic to understand what design makes sense for your project specification and needs. Let's do online pcb design and manufacture together.