In a recent survey, we asked the following question: What are your biggest problems related to flex design? Here are just a few of the answers, edited slightly for clarity.
1. The signal integrity of signal paths through both flex and rigid parts of rigid-flex PCBs.
2. Understanding how to design a flexible PCB that is easily manufacturable and robust.
3. None. We design them correctly!
4. Mechanical dimensioning and sizing to fit the required application.
5. Our designers need to learn more about the FPC fab process.