Today’s electronics continue to get smaller in size but with increasing design complexity. More and more, PCB designers are using rigid-flex PCBs to carry-out these high complexity design requirements.

When working on the Rigid-Flex PCB Layer stack-up, an essential factor to consider is the stresses that flex board experiences due to bends and curves of the PCB.

So, use these 4 tips to help you create a stack-up for a robust rigid-flex PCB:

1. Keep the flexible section symmetrically in the center of the rigid PCB layers.

Rigid Flex PCB layer stack-up

2. When routing traces on flexible sections of the PCB, make sure that the traces are running perpendicular to any bending lines. This ensures that the copper does not fatigue and wear out early.

Rigid Flex PCB trace routing

3. Use curved traces to get around corners instead of the 45 or 90 degrees straight traces, which are usually used on a rigid PCBs. With flex PCBs bend the copper need to bend in an arc formation so that it doesn’t fatigue.
4. For a two-layer flex portion, the traces should be staggered so that they don’t end up one on top of the other. This way avoids a thickness build-up for traces where the copper from one layer is directly on top of another.
Using rigid-flex PCBs lets you achieve the form factor and weight requirements for today’s complex electronic products. When properly designed, you can ensure the durability and reliability of the device.