勛圖tv 繚 ENGINEERING GUIDE
Kapton FN: FEP-Coated Film and Composite Thickness
DuPont Kapton FN combines polyimide film with FEP coating on one or both faces. Its selection centers on the coated interface and complete thickness, rather than treating FN as another name for uncoated HN. The online stack worksheet helps organize these layers without assuming a production sealing recipe.
Read the complete film code
FN constructions differ in the polyimide and coating gauges and in the coated faces. Ask for the complete grade and current drawing convention. A nominal overall thickness does not tell the assembler which side can form the intended bond. Preserve orientation through cutting, labeling and assembly when the two faces differ.
Construction and decision boundaries
| Review item | What this page establishes | What remains project-specific |
|---|---|---|
| Base | Polyimide film | Full gauge code required. |
| Coating | FEP on one or both faces | Preserve face orientation. |
| Stack tool | Sum of specified physical layers | No heat-sealing recipe is inferred. |
Stackup thickness interval sum
Stackup thickness interval sum
Use the current inputs and keep the assumptions
Start with the example only to inspect the units and the calculation boundary. Replace every assumption with a value tied to your own document or measurement. An empty numeric field is not zero. The review-reference field is a local label; avoid entering customer names, confidential part numbers or other private information into a public worksheet.
After calculating, read the notes alongside the numerical result. Changing any input invalidates the displayed result and disables its download until you calculate again. For a comparison, keep the units, geometry, material condition and measurement boundary consistent. A long decimal result does not imply equally precise input data. The downloadable record stays on your device and can be attached manually to an inquiry. It is not automatically transferred into the Contact form.
If an input is unknown, identify the person or document needed to resolve it. Do not fill a gap with a favorable generic value simply to obtain a result. You can request a material or fabrication review without using the tool. The arithmetic illustrates a relationship; it does not accept a construction, certify a material, establish current pricing or replace a supplier process specification.
| Input | What to establish before using it |
|---|---|
| Review reference | Nonconfidential revision label. |
| Layer entries 繚 CSV | All dimensions in mm. Use each physical thickness once. Minus and Plus are positive absolute deviations, not percentages. |
Optional cost comparison from your own allowances
Use a quotation or a clearly labeled internal assumption for each input. Keep the quantity, construction and inspection scope the same when comparing alternatives. This uncalibrated planning model adds entered values; it contains no current market rates and does not issue a 勛圖tv quotation. You can contact the team without completing it.
Optional project allowance comparison
Describe the interface to be joined
Heat-sealable coating does not mean it will bond every surface under a generic temperature setting. Identify the mating material, surface condition, overlap and applied load. Establish the sealing process and acceptance method with the material supplier and the actual assembly route. Keep trial specimens representative of the surface finish and contamination controls used in production.
| Review item | What to establish |
|---|---|
| Layer identity | Polyimide gauge and every coating layer |
| Orientation | Coated face and mating surface |
| Acceptance | Joint and dimensional inspection method |
| Limit | Thickness sum does not establish sealing conditions |
Account for each layer once
Enter polyimide and every FEP layer separately in the thickness worksheet, with tolerances from the controlled requirement. As a hypothetical arithmetic example, 25 繕m film plus two 2.5 繕m coatings totals 30 繕m before other assembly layers. The tool sums nominal and limit values; it does not predict squeeze-out, shrinkage or a pressed bondline. Use measured finished values where the assembly fit depends on them.
Review thermal and electrical paths
A coated film is a composite. A bulk number from HN film cannot describe every direction and temperature of the FN stack. Where heat transfer is important, compare the full interface with MT thermal-film planning, including any added adhesive or air gaps. For insulation, edge coverage and the mating geometry remain relevant even if the base film has strong dielectric test results.
Separate coating from circuit protection
FN film is not a substitute instruction for conventional flex coverlay. A coverlay opening review considers registration and resin intrusion around circuit pads. If a coated insulating piece is used near circuitry, show its boundary and attachment method explicitly. Otherwise a fabricator may interpret a general film note as a different manufacturing operation.
Send the sealing and fit question together
Include the exact FN designation, face orientation, mating material, overall clearance and intended exposure. Ask what evidence supports the proposed joint and how that joint will be inspected. Compare costs on the converted assembly item, including cutting and attachment, rather than the price of an unspecified roll of film.
Make the coated face visible on the assembly drawing
| Review point | Input to record | Decision or verification |
|---|---|---|
| Orientation | Mark each FEP-coated face and the mating surface on a section drawing. | A mirrored part must not silently put the coating on the wrong interface. |
| Seal sample | Record overlap, surface preparation, applied pressure and the actual temperature history. | Judge the intended joint, including edge lift and peel mode; do not borrow a generic press cycle. |
| Thickness allowance | Include every coating once in the fit calculation. | Compare the sealed region with the unjoined region where the assembly has a local step. |
Use the review points above alongside the worked example on this page. Record the chosen inputs with the drawing revision and send unresolved items with the enquiry. A supplier response should identify the proposed construction and the evidence needed for release.
Standards, source context and limits
Use the edition, amendment and material-document revision named in the purchase agreement. A standards title, marketing label or supplier product family does not establish that a particular lot meets a requirement. Public summaries are useful for scope; the controlled specification and applicable test method govern acceptance.
The examples on this page are illustrative engineering scenarios. They are not 勛圖tv production records or guaranteed material values. Source links identify the organizations responsible for the referenced information. Confirm applicability to the exact grade, construction and test condition before carrying a number into a drawing or qualification report. For a flex board, distinguish the design requirements in IPC-2223, finished-board qualification and performance in IPC-6013, and the material scopes of IPC-4202, IPC-4203 and IPC-4204. These cover different deliverables; naming them does not certify the material or factory. State the contracted revision and applicable material sheet. Source review date: 3 October 2026. Legacy designation, present availability and an approved replacement are separate questions.
For fabrication scope and the agreed construction requirements, see PCB manufacturing.