2 Layer Flex PCB: The Future of Innovative Electrical Devices

In our increasingly technological world, there is always a need for new and innovative electrical devices. Rigid Flex PCBs are one of the latest innovations in this field, and they offer a number of advantages over traditional PCBs. A Rigid Flex PCB with low quality will often be subject to overheating and might not function as well.

It will also ruin your product and makes you lose your investment. With rigid flex PCB, though, these limitations can be overcome for more innovative and efficient devices. In this blog post, we’ll explore the benefits, material, design, manufacturing, cost, and applications of rigid flex PCBs. Stay tuned!

What Is 2 Layer Rigid Flex Circuits?

A rigid flex PCB refers to the class of flex circuits that consists of two conducting layers (copper layers) along with insulation layer. The insulation layer is present just in the center of conducting layers in rigid flex circuits. This rigid flex circuits are perfect for products having high requirement of circuit density.

Components Used in Manufacturing of 2 Layer Rigid Flex Circuits

Different types of components make up rigid flex ciruits. Common components among flexible circuits include:

  • Laminate
  • Prepreg
  • Soldermask
  • Copper foil

In rigid flex circuits another name of laminate is copper clad laminate. You can use heat and pressure in rigid flex circuit to join multiple sheets of prepreg making up copper clad laminate.

The prepreg refers to the glass fabric in rigid flex circuits. Flexible printed circuit boards contain coating of resin which then later dried in a flow prepreg treater. The prepreg in flexible printed circuit board act as a resin holder.

On the outer side of board a coating present which is refer to a Solder mask in flexible circuits. The external side of flexible layers in multi layer flex circuits requires special protection becuase if left unprotected they face corrosion.

Etiching carried out on conductive rolled annealed copper layers to convert them into circuit form and make them a better conductor. After this you can use prepreg to laminate them as discussed earlier in multi layer flex circuits.

Materials Used in Making Multi Layer Circuits

Different materials play their part in making up flexible printed circuits. Each material have many benefits. Some of the key layer flex circuit materials include:


These materials are popular becuase of their electrical insulation. They have low dielectric constant and have very high temperatures reliability. They features plane surface and have self extinguishing properties on catching fire in layer flex circuit/ rigid flex pcb assembly.


Another name for polyester material is PET (Polyethylene Terephthalate). These materials offers unmatchable tolerance when it comes to moisutre and chemicals in flex circuits/ flexible PCBs assembly. It offers low heat resistance in rigid boards. Thus, reducing soldering or assembly affect.


Polyimide serve as a key element in PCB. In flex circuit these materials refer to the polymeric film/ polyimide. Polyimide plays its role as flexible PCB substrate. The polyimide offers sufficient heat resistance in rigid boards assembly or either in flex circuit. Polyimide also has stability to high temperatures compared to counterparts. In rigid boards flex circuit polyimide offers high flexibility and resistacnce to tear. Polyimide does not break when you bend it.

Polyether Ether Ketone

This material in rigid PCBs/ rigid board features higher radiation sustainability and chemical resistance. It also has the ability to resist melting even at higher temperatures in flexible PCB. They have not remarkable tear strength but have remarkable resilience and elasticity in flex circuit or flexible pcbs.

2 Layer Flexible Circuit/ Flex PCB Stackup

The stacking of flex pcbs consist of following:

  • A substrate or laminate also known as a base film in flexible circuit/ flex pcb.
  • Two Rolled Annealed Copper Layers
  • Four Adhesive Layers
  • Two Protective/ Covering layers

Base film features through holes. You can use these holes to connect copper layers (base material) in flex pcbs/ flexible circuit. Later you can attach conductive copper layers using adhesive to base film. Adhesive plays a great role in PCB. The adhesive connect ensuring durability and reliability of layers. It offers almost zero bend and less thickness. In the end you attach protection coating on either ends of flex pcbs. It act as organic solderability preservative. You can also use white tin as protective coating for copper layers.

Design Considerations of Low Thickness Flex Board

Design capabilities typically matters when you are manufacturing typically low thickness flex board. Some of the main considerations are as follows:

  • When a single layer serve the purpose avoid utilizing extra layer
  • The price depends on the circuit complexity, material utilization, flexibility and timeline
  • Always use light weight copper, using 1/3oz copper is beneficial
  • You should use 0.25 mil size of hole, it leads to less cost association
  • In applications using higher frequency hard stiffner is appropriate
  • Golg finish immersion is more profitable
  • Higher material use leads to low overall cost association

Applications of Dual Layer Flex Circuit PCBs

There are wide applications of dual layer flex circuit PCBs. The main applications of flex/ flexible PCB technology include:

  • The digital camera employ flex/ flexible boards. The flex boards of PCB have capability to serve as heat, temperature, humidity, chemical, radiation, and light detectors. They do not break while bend. This represents high strength of flex/ flexible boards.
  • In RFID systems you can use them during patients implantation process. High volume of thin flex widely used in calculators, cell phones, mobiles, robotics, or human machine interface. Thin flex board widely used in excercise devices, pace makers, and hearing aids specially in healthcare industry.
  • For example engineers use low thickness flex board in PCB process to manufacture solar cells. Engineers also use PCB in performance testing and service of solar circuits. Shielding capabilities combining with low weight and thickness typically suitable for computers, vehicles, and power applications. For example in space routing and shielding applications the low thickness/ lighter flex PCB serve best when it comes to performance. The laminated layer in PCB is perfect mix when you need your device routed.
  • Dual layer flex PCB has well suited applications specially in USA market. Various combination of specifications serve purpose in this regard.


The future looks bright for 2 layer flex PCBs specially in USA. They are versatile, efficient, and have a wealth of potential applications. Manufacturers who invest in this technology now will be well-positioned to take advantage of the growing demand for these innovative electrical devices. If you’re looking for a way to stay ahead of the curve, consider investing in 2 layer flex PCBs today.

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