Improved controlled impedance signal characteristics.Improved flexibility due to reduced flex thickness.Reduced flex thickness due to the elimination of the adhesive layers.To address the use of adhesives in copper-clad flex laminate, adhesiveless construction was introduced.įollowing are the features of adhesiveless materials: The typical layer thickness ranges from 0.5 to 4mils. Polyimide is also extremely uniform in its thickness due to its “cast” manufacturing process. The lack of woven glass reinforcement eliminates variations in Dk. The thickness of flex materials is uniform with an improved Dk value ranging between 3.2 and 3.4. Flex materials offer better material properties when compared to rigid PCBs. Polyimide is the primary material used for both flex core layers and coverlay layers.
![flex pcb flex pcb](https://www.protoexpress.com/blog/wp-content/uploads/2020/02/Flex-PCB-3-Copy.jpg)
Another option is removing sections of the flex where there is no circuitry, although this must be removed lengthwise and will require routing afterward.
![flex pcb flex pcb](https://www.mokotechnology.com/wp-content/uploads/2019/10/flexible-pcb.jpg)
Using cutouts will reduce the amount of material required to bend. If there are no traces in the bend region, the bend radius can be minimized through the insertion of cutouts, or slots.
![flex pcb flex pcb](https://www.flexiblecircuit.com/wp-content/uploads/2015/08/Rigid-Flex-Large.png)
However, heat-forming is used primarily for ease-of-installation tighter bend radius just happens to be one of the additional capabilities it provides. One of the benefits of heat-forming is the tighter bend radius it provides. The steel jig is then inserted into an oven. Heat-forming requires a steel jig, as it forces the board to lie a certain way. Flexibility is an important feature of the flex PCBs that enables the PCB designers to use them in tiny packages. Plated through-holes should be avoided in the bend area, conductors should be staggered in multilayered circuits (for greater effectiveness), and conductors smaller than 10 mils should be placed within the neutral bend axis where there is no tension or compression during flexing. To know more about flex PCB applications read our article Why Are Flex PCBs Used in Medical Devices and Wearables? When laying out the bend areas, avoid 90-degree bends that cause high strain. Calculating bend radius can be done based on how many layers are in the flex PCB, as explained in our Flex Design Guide. The figure below will help determine how thick you can make your circuit. This ensures your design can allow for the necessary number of bends without damaging the copper. To know more about military-grade PCB specifications, read our article: Military-Grade PCB Design Rules and Considerations.īend radius-the minimum amount of bendiness for the flex area-must be properly identified early in the design. These PCBs are used in very harsh conditions such as spacecraft and military applications. A dynamic board’s design needs to be more robust in nature, as flexing will be done on a regular basis-and will need to withstand tens of thousands of bends. A static board is considered bend-to-install and will flex less than 100 times in its lifetime. The amount of times it can bend, or application, determines whether the board will be a static or dynamic board. It is vital to know two things about flexibility: how many times the PCB will be flexing, and to what extent the PCB will flex. Let’s look at five things you should know going into your first attempt at flex PCB: Understand the bendability/flexibility of your flex PCB. There are plenty of ways to ensure a high-quality flex PCB design.