The stackup is the design
A rigid-flex build is a flex core sandwiched between rigid sections, bonded with no-flow prepreg. Everything that matters — bend radius, impedance, thickness — follows from how many flex layers you use and where the stiffeners stop.
Options by layer count
- One flex layer — the simplest and cheapest, suited to a single bend that stays put after assembly.
- Two flex layers — allows crossing conductors and controlled impedance in the flex tail.
- Multiple flex layers with rigid sections — up to 12 layers in our build, for assemblies that fold into a housing.
Details that decide yield
- Keep the copper balanced around the neutral axis of the bend.
- Route conductors perpendicular to the bend line, never along it.
- Use teardrops at pad transitions and avoid via holes in the bend region.
- Specify the stiffener material and thickness where connectors mount.
What we need to quote
Send the layer stack, the bend location and radius, the stiffener drawing and the connector footprints. We laminate rigid-flex up to 12 layers, with 0.075 mm trace and spacing and board thickness from 0.1 mm to 6.0 mm, and we will flag any stackup that cannot survive the stated bend.
