Process of Designing a Flexible Circuit Board

In the first step of designing a flexible circuit board, it is necessary to determine the layout and choose the component placement. This is done by analyzing the components and their data sheets to make sure that they will work properly in your design. Once the final layout has been designed, the PCB/layout provider will provide a gerber file and a fabrication drawing for your approval. The flex-rigid or multi-layer circuits will then be built layer by layer, just like the typical rigid PCBs you are used to.

Once the design is approved by the customer, it will be sent to a fab house for production. Depending on the layout, it may be single-sided, double-sided or multi-layered. During this process, the flex-rigid or multi-layer will be laminated to the copper core with a choice of materials such as polyimide or FR4. It is important to use an IPC standard for the copper thickness and conductor width in order to maintain proper electrical performance.

Next, the flexible circuit board or multiple-layer will be etched to expose the copper. This will then be finished with a solder mask and silkscreen. This step will also include identifying the component locations and the pad/land terminations on both sides of the flex-rigid or multi-layer. Lastly, the flex-rigid or flexible circuit will be cut to length and terminated with connectors if not embedded in the rigid PCB.

The Process of Designing a Flexible Circuit Board

The extreme ends of a flex circuit can have mechanical stiffeners added to help protect them from bending at tight radii or in repeated flex cycles. These stiffeners can be made from a wide variety of materials, but most often they are a layer of polyimide with a layer of adhesive or FR-4. One of the key benefits of a flexible circuit board is that it can be bent and shaped to fit inside the device in which it will be installed. This can save space and weight, as well as reduce the overall size of the product.

There are a number of other benefits that come along with a flexible circuit board, such as the ability to create a product that fits into a specific enclosure or space, or that can be wrapped around the outside of a cylindrical device. These types of devices can be more difficult to design for with traditional rigid circuit boards. Using a flex or rigid-flex circuit board can help designers solve these challenges and develop better products.