Flex and Rigid-Flex boards
Please keep in mind the following Design-Rules for your Flex- or Rigid-Flex circuit boards.
For designers of flexible circuit boards we recommend the IPC-2223 Guideline / Design guidelines for flexible circuit boards, which is available from the IPC online store or in German, from the FED website.
Calculation of the bending radius
The minimum bending radius r results from the factor 6 to 25 (depending on the number of layers or application) multiplied by h, the overall height of the flexible part.
2 layers flexible PCB; overall height of flexible part: 300µm
minimum bending radius r = 10 x 300µm = 3000µm = 3mm
Flexible PCB for dynamic installation; overall height of flexible part: 400µm
minimum bending radius r = 25 x 400µm = 10000µm = 10mm
Design of bending areas
Design of bending areasDivide wide conductor traces into narrower conductor traces in the bending area.
Fill open regions in the bending area with blind conductors.
Ensure a perpendicular path of the conductor traces to the bending axis. Avoid pads plated-through holes in the bending area.
The bending area may be optimized depending on the application.
For 2 or more flex layers, please ensure an alternating arrangement of the conductor traces on the front and back sides of the flexible portion.
Use curves instead of corners in the conductor trace path.