Engineering worksheet

THICKNESS WORKSHEET / µm → mm

Build your local stack.

Enter each physical layer once. The example values are editable nominal inputs, not a released construction.

NOMINAL FLEX REGION0.136 mm

With local stiffener: 0.261 mm

The flex-region total excludes the stiffener. Add all relevant plating, shielding and bondply. Final thickness depends on actual construction and process tolerances.

Choose a section before entering values

Name the region: free flex, exposed terminal, reinforced terminal, component island, or rigid section. Enter only layers physically present at that section, keeping all inputs in a consistent unit system. The stackup drawing guide helps define this section. A connector contact area may omit coverlay that exists immediately behind it.

Worksheet input audit

Stack featureSpecifyEngineering question
RegionExact section and bounding surfacesDoes every entered layer exist here?
UnitsConsistent thickness unitsAre conversions explicit?
CopperBase or finished definitionHas plating been omitted or counted twice?
BondingNominal or finished assumptionWhat needs process confirmation?
OutputNominal sumWhich tolerance remains unresolved?

Track what each number means

Label values as supplier nominal dimensions, proposed finished dimensions, or temporary assumptions. A blank should mean missing information, not zero thickness. Separate base copper from a completed copper requirement to avoid double counting plating. Use reinforced-thickness planning when the output must match a connector or enclosure interface, and request fabrication review of bondline assumptions.

Use the result to improve the brief

Compare the nominal total with the available mechanical envelope and list the remaining questions. If the total is incompatible, revise the architecture or proposed construction rather than merely deleting inconvenient layers. Have the fabricator confirm the completed thickness and tolerance at critical locations. Save the input list with the RFQ so the same total can be reproduced and reviewed after a material change.

Before you release the design

  • Select and name a region.
  • Include all protection and support layers.
  • Flag unknown inputs.
  • Check copper for double counting.
  • Request a finished-thickness review.

Watch points

  • Adding nominal material tolerances without an agreed method does not establish a finished acceptance limit.

Practical questions

Does the worksheet predict bending reliability?

No. The total can be an input to mechanical planning, but actual construction, geometry, motion, and qualification remain separate.

Can zero represent an absent layer?

If the interface supports omission, remove the layer from that region. Do not use zero to hide an unknown thickness for a layer that exists.

Technical references

References support the material or design context. Check the exact grade, part number, document revision and project conditions before release.

Updated 27 September 2026 · Technical content policy · Engineering guidance supports project review; the agreed drawing defines the build.