Flex Circuit

What is Flex Circuit?

It is possible to bend a flexible PCB, sometimes referred to as flex printed circuit or flex circuits, into the desired shape. They are frequently employed in high-temperature and high-density applications. The substrate material used in flex designs is polyimide or a transparent polyester film, both of which have good heat resistance, making them ideal for solder mounting components.

How is a flex circuit made?

Flexible PCBs are made using polyimide as the basic substrate. Given that this material is more expensive than FR-4, it must be utilized with caution. Circuit boards are kept close to one another using the nesting technique to make proper use of the polyimide material.

Here it is 5 Steps of manufacturing flexible circuit boards

Step1. Looping

The servicing length and circuit assembly, which is the amount of extra material you add over the designer’s restriction, are guaranteed by the service loop.

Step2. Sizing Conductor

On the board, conducting material is thin copper. The circuit’s flexibility and suitability for dynamic applications are due to the thin copper.

Step3. Etching

Any isotropic losses that may occur during the manufacturing process are made up for by the etching procedure. The line width loss in this method is halved by the thickness of the copper foil. Conductor, etch mask, and the various conductor types employed are some of the variables that affect line width.

Step4. Routing

It is straightforward to route. Routing guarantees less stress and enhances folding and bending.

Step5. Ground Planes

Ground plane construction will lighten the board and improve circuit flexibility. Before applying filleting, you must first make holes where you can expand the pad area to distribute stress. For applications involving dynamic flex circuits, add adhesive-backed films. Before applying photo-imaginable liquid and film polymers that serve as a solder mask and shield the circuitry from both internal and external harm, you must first apply screen-printable liquid overcoats.


What are flexible circuits used for?

Although flexible boards are useful in a variety of applications, rigid circuit boards must still be used in some cases. due to the low cost and versatility of rigid boards in high-volume automated fabrication applications.

Applications that call for greater performance, high accuracy, precision, and frequent flexing are a good fit for flexible circuit boards. Below devices usually contain flexible circuits board:

  • Bar code equipment
  • Airbag systems
  • Manufacturing devices
  • Battery packs
  • Avionics
  • Satellites
  • Motion systems
  • Medical devices
  • Semiconductor test
  • Ultrasound probes
  • Fuel pumps
  • Antilock brakes
  • Cameras
  • Solar cells
  • Printers
  • Automotive
  • Flexible batteries
  • OLED displays
  • LCD displays
  • Mobile phones

There are 4 common types of flex circuits

1. Single Layer Flexible PCB

As its name suggests, the single-layer flexible PCB has just one electrical layer, which is attached to the flexible dielectric membrane. On one side of the PCB alone, the electric components are supported.

2. Double Layer Flexible PCB

You can connect electrical components on either side of the conductive layer on the double-layer flexible PCB since it has conductive layers on both sides.

3. Multiple Layer Flexible PCB

Three or more conductive layers, separated by a dielectric substance, make up the multi-layer flexible PCB. High board flexibility is ensured by the uneven lamination, and the bonding area’s lamination thickness is typically lower.

4. Rigid-Flex PCB

In comparison to conventional circuit boards, the rigid-flex PCB offers a higher component density since it combines stiff and flexible circuit boards.

Why flex circuits are popular?

There are several benifits using flex circuits board below:

  1. Additionally, it has been demonstrated that rigid flex circuits are denser and use lighter components, freeing up more space for extra features.
  2. Less pieces and interconnections are required for rigid circuit boards. Additionally, rigid circuits can be constructed on intricate designs with fewer interconnections.
  3. The use of mechanical connectors is quite low. The system is shown to be more dependable because connections points are used less frequently.
  4. They can be used in hostile circumstances. Increased heat dissipation is also made possible by the thinner flex circuits. Similar to this, the streamline flow permits the movement of cooling air, improving airflow.
  5. Additionally, the flexibility helps to lessen and absorb the effects of any vibration.
  6. They are lighter and take up less room. The thinnest substrate materials are found in flex circuit boards. They may just be 0.004 inches thick. It also results in a smaller package.
  7. Flex circuits can be flexibly constructed to fit all intricate layouts. Its versatility is the reason behind this. Placement is also possible around folds and edges thanks to the elastic nature.
  8. They decrease production errors and demand less manpower. The cost and time of assembly are also reduced.
  9. Due to the precise design and fully automated manufacture, there is a significant reduction in assembly errors.


Why are flex circuit board so expensive?

Due to the additional raw materials needed and generally lower yields, rigid flex PCBs cost about seven times as much as identical rigid PCBs. In the future, if the flex circuit consume volume more the the Rigid PCBs, its price may be can come down a lot. But at present, the flex circuit cost expensive than rigid PCB cost can’t be avoided

Why choose us?

At INTOPCB, flex circuits solutions are in abundance. We are happy to design and construct various types of flexible circuit boards as a MIL-P-50884 and IPC-6013 manufacturer. Each product is rigorously tested to ensure that it satisfies our high performance criteria as well as the assembly standards established by J-STD-001 and IPC-610. The Raytheon Supplier Excellence Gold Award was given to FCI because we have consistently maintained high quality standards, making us one of the top OEM suppliers to the aerospace and defense sectors.

We produce flexible printed circuit with great dependability to meet any application’s performance needs. Select from stiff flex circuits, multi-layered circuits, double-sided circuits, and single-sided circuits. Additionally, we can create specialized flexible printed circuit boards!

At our cutting-edge manufacturing plant, each component is developed and put together. To give you industry-leading solutions, we only employ the best materials and tools during production.