Part of the rigid-flex circuit board resource.
Stackup builder
Map layer continuity across rigid and flex regions. This conceptual drawing is not a fabrication stackup.
Enter your requirements to begin. JavaScript is required for calculations.
A regional layer map for an early discussion
The builder shows which copper layers remain in the rigid region and which continue into the flexible span. It generates a simplified cross-section and a table that can be copied into a design note. It is intended for construction conversations, not direct fabrication. It does not generate drilling data, material purchase specifications, lamination instructions, controlled-impedance geometry, or manufacturing tolerances.
Count the flexible copper only once
Total rigid-region copper layers means the number of copper layers through the rigid portion of the finished board, including the flexible layers embedded there. If you choose six total layers and two flex layers, the drawing contains six copper layers, of which two continue through the flexible region. It does not create eight. This convention should be written next to any shorthand stack description you send to a supplier.
Understand the thickness allocation
The tool converts copper thickness from micrometers to millimeters by dividing by 1,000. Its conceptual flexible thickness equals flex-layer count times copper thickness, plus 0.025 mm for each dielectric interval between flex copper layers, plus the selected coverlay thickness on each side. Coverlay input includes its adhesive. The 0.025 mm interval is an explicit illustration assumption, not a prescribed laminate or fabricator capability.
Check the remaining rigid dielectric budget
The tool subtracts all rigid-region copper, the selected coverlay contribution, and the illustrative flex dielectric contribution from finished rigid thickness. The remainder is an allocation for rigid and bonding dielectrics; it is not an engineered core-and-prepreg schedule. Implausible inputs with inadequate remaining thickness are rejected. Plating, copper distribution, press behavior, material tolerances, and the actual coverlay termination can change the real result.
Air gaps require more information
Selecting an air gap marks the intention to leave selected flex sublayers unbonded. It does not assign a gap thickness or calculate individual bend paths. A released air-gap or bookbinder drawing must identify bonding boundaries, free lengths, relative movement, termination details, and the folding sequence. The fabricator needs that information to evaluate assembly and processing. A simple two-dimensional illustration cannot validate a folded structure.
Read the SVG as a concept
Color distinguishes copper, flexible dielectric, and rigid material. Vertical spacing is chosen for legibility rather than physical scale. The rigid edge marks where a different regional construction begins, not a universal registration tolerance. The exported SVG is labeled as a concept and carries the selected copper continuity. The copied table reports layer number, regional continuity, and copper thickness so the same interpretation can be shared in text.
Complete the stackup before routing critical signals
Replace the illustration assumptions with the fabricator’s material designations, pressed thicknesses, finished copper definition, coverlay construction, and approved tolerances. Agree reference-plane placement and impedance targets per region before finalizing trace geometry. Review transition keep-outs and any microvia architecture against the same revision. Use the RFQ button to transfer the planning inputs, then attach the authoritative drawing when it is available.
Related design decisions
Review the design guidelines, regional stackup guide, material-system requirements, and cost comparison guide alongside these results.
Questions about this tool
Is the SVG ready for fabrication?
No. It is a conceptual layer-continuity drawing with explicit thickness assumptions.
Does the total include the flexible copper?
Yes. A six-layer rigid region with two flex layers has six total copper layers in that region.
Does the builder calculate impedance?
No. Obtain a material-specific stack and impedance review from the fabricator.