Rigid-Flex circuit boards are composed of a combination of rigid and flexible circuit boards that are permanently connected to one another.
The proper application of Rigid-Flex circuit boards offers optimum solutions for difficult, limited space conditions. This technology offers the possibility of a secure connection of device components with the assurance of polarity and contact stability, as well as a reduction in plug and connector components.
Additional advantages of Rigid-Flex boards are dynamic and mechanical stability, the resulting 3-dimensional freedom of design, simplified installation, space savings, and maintenance of uniform electrical characteristics.
Use of Rigid-Flex circuit boards can reduce the total cost of the final product.
A standardized manufacturing process following IPC guidelines guarantees a reliable and simultaneously an economical product, which is UL certified (UL94 / V-0); application of the UL logo is available at no extra cost.
Depending on the application, the complete Rigid-Flex board may be manufactured either symmetrically with inward flexible layers, or asymmetrically with outward flexible layers (see Layer buildup for Rigid-Flex circuit boards).
We recommend the IPC-2223 Guidelines to circuit board designers for flexible circuit boards. This is available (at cost) from the website of the IPC (www.ipc.org), or in German from the FED website (Fachverband Elektronik-Design e.V., a German trade association for electronic design), and can there be found there under Normen/Dokumente - FED-Shop.
Technical options for Rigid-Flex
| Options | Notes | |
|---|---|---|
| Layers | 2 to 24 layers, incl. "flying tails" | Layer buildup |
| Conductor width min. | 75µm | |
| Annular ring min. | 100µm | |
| Via min. Ø | 0.15mm | |
| Surfaces | Chemical gold (recommended), immersion tin, HAL lead-free | Surfaces |
| Materials | Polyimide, high Tg polyimide, FR4, FR4 high Tg | Materials |
| Material thickness | Polyimide starting at 62µm doublesided, FR4 starting at 100µm | |
| Max. size | 250mm x 450mm | larger on request |
| IPC class 3 | yes | |
| Solder-stop | Coverlay, flexible solder-stop | |
| Solder-stop colors | green, white, red, blue, black | |
| Peelable Solder-stop | yes | |
| Marking print colors | white, black |
Please also refer to our Design-Aid for flex and rigid-flex PCBs.
RIGID-FLEX PCBs, 2 - 24 LAYERS
Inclusive
- 0.1mm tracks, annular ring
- 0.2mm drills, unlimited
- 0.4mm via pad
- Tooling costs
- Surface chem. Gold
- Polyimid 25µm / 50µm
- Copper 18µm / 35µm
- 2x solder-stop green
- Coverlay, flex area
- 1x Stiffener
- E-Test, Design-Rule-Check
Optional: Impedance control, blind & buried vias, SBU, legend print, …
| e.g. 80mm x 100mm | U-1F2R 2 layers | WD | S-2F4R 4 layers | WD |
|---|---|---|---|---|
| 5 pcs. each | 97.13 € | 15WD | 132.74 € | 16WD |
| 10 pcs. each | 52.05 € | 15WD | 71.03 € | 16WD |
| 25 pcs. each | 27.52 € | 16WD | 37.67 € | 17WD |
| 50 pcs. each | 19.16 € | 16WD | 26.40 € | 17WD |
UL certification for Rigid-Flex
At Multi-CB, you also get Rigid-Flex circuit boards with UL certification.
Multi-CB’s UL identification number for flex and Rigid-Flex circuit boards is: E489719.
Rigid-flex printed circuit boards FAQ
Rigid-flex is always suitable if you want to save on connectors and cables, have to bridge several levels in very confined housings or if there is a dynamic load on the connection between rigid assemblies - e.g. in folding devices, vehicles or medical devices.
Yes, the rigid FR4 areas are suitable for SMD assembly like conventional PCBs. The flexible areas can also be assembled - with appropriate design rules - usually with small components. We support you with the design.
Above all, the following is crucial: transitions between rigid and flexible areas must be mechanically relieved (no sharp edges). The bending radii of the flexible areas should be generously dimensioned. Here you can find our: Design-Aid for flex and rigid-flex printed circuit boards.
The flexible ends can be inserted into the mating part using ZIF connectors, hot-bar processes, soldering or directly as flexible cables. The contact surfaces are usually plated with chemical gold and designed for multiple mating cycles.
You can directly use our circuit board calculatoror send us an enquiry by email. We will be happy to provide you with a customised quote. Our CAM team will advise you as early as the design phase.