Arlon 35N PCB: Polyimide Cure and Thermal Review

Keep 35N identity and flame rating together

The official version 1.9 sheet describes 35N as pure polyimide, with a Tg statement at or above 250°C and UL V-1 recognition context. It also reports typical integrated Z expansion of 1.2% over 50–260°C. These are material properties and recognition statements, not qualifications of a RAYPCB facility or an end product.

If V-0 is a fixed requirement, examine the exact 33N or other approved material route. Do not relabel 35N as V-0 because both products belong to a high-temperature family or share a similar Tg headline.

Evidence and construction decision

Review the thermal sequence that the copper interconnect sees

List lamination, finishing, assembly and allowed rework. Identify the hole families and thicknesses that are most sensitive to that sequence. A high transition temperature can be relevant, but plated-hole reliability also depends on copper construction and the actual process.

The finished PCB is mechanically constrained, and its resin response changes with temperature and time. A source table should therefore be connected to a representative test or inspection plan. It should not be used to predict an unlimited number of reflow cycles.

Treat a faster cure as a qualified process opportunity

The supplier describes a reduced-temperature and reduced-time route relative to traditional polyimide processing. That is not a universal permission to shorten every press cycle. The actual book construction, heat transfer and product-temperature history need to be considered by the manufacturing team.

Record the approved guide and process revision. Keep equipment settings separate from measured product conditions. A press setpoint does not prove that the center of a thick assembly reached the required cure history.

Piecewise free thickness expansion

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 RAYPCB quotation. You can contact the team without completing it.

Use expansion arithmetic as a transparent comparison

The worksheet integrates entered coefficients below and above a selected transition. It helps expose how the assumed temperature interval affects free thickness movement. The loaded example is generic and should not be described as a 35N material profile.

The output excludes copper constraint, polymer relaxation and accumulated damage. It cannot establish fatigue life or a safe operating temperature. Use it to prepare questions, then obtain the material and construction evidence needed for the actual design.

Compare systems with the relevant difference visible

P96/P26 is another polyimide system with its own resin and flame context. 85NT changes the reinforcement architecture and in-plane expansion task. Those differences should remain visible in a comparison instead of being compressed into a single high-Tg category.

If package expansion is the controlling problem, a free-thickness model may not be the right decision tool. If the problem is hole reliability, an in-plane CTE headline is not enough. Define the failure mechanism before selecting the comparison.

Prepare a 35N manufacturing proposal with accountable inputs

Send the exact material requirement, stackup, copper, holes, assembly exposure, flame requirement and acceptance scope. State whether alternatives are allowed and what evidence is needed for approval. Include quantity and any required material or process records.

The optional allowance model contains no polyimide market rates. Compare supplied prices only on the same build and qualification scope. The next useful result is an agreed construction and verification plan, not a generic claim that polyimide automatically solves every thermal reliability problem.

Close the material and construction decision together

The finished board combines a dielectric, copper patterns, holes, surface coatings and a manufacturing history. Its behavior cannot be inferred from a family name alone. State the supplied grade, reinforcement, thickness, copper and processing conditions that matter to the intended application.

Keep handling and assembly requirements with the fabrication drawing. A thin panel, punched outline or unusual support condition can change the production route even when the electrical circuit is simple. Ask the fabricator to review the actual features and panel format rather than assuming a dimensional example represents a production capability.

For cost comparison, hold the drawing, quantity, test scope and acceptance requirements constant. Record one-time tooling separately from recurring work, and distinguish raw material utilization from accepted-board yield. Any calculator on this page uses supplied assumptions; an actual quotation requires the files and an agreed scope.

A source-qualified table should be read alongside the exclusions and footnotes, not separated from them. If the supplier limits an application, identify whether that limitation affects the current design before requesting a price. A familiar family classification does not override an explicit restriction, and a positive calculator result cannot remove it.

For a repeat build, compare the newly proposed supply with the previously approved material record. Exact grade, manufacturing site where relevant, foil treatment, reinforcement and dimensional basis can matter. Define which changes require notification and which need technical approval. This avoids turning a purchasing substitution into an unnoticed design change.

Receiving records should support the agreed identity and traceability requirement. A certificate for a raw material, a finished-board inspection report and an assembly test result cover different boundaries. Request the records that actually answer the project questions rather than collecting unrelated certificates.

When a source contains conflicting values, keep the discrepancy visible until a controlled revision or written supplier response resolves it. Do not create a new table by combining the most favorable entries from several sources. The released drawing, material list and quotation should all describe the same accepted construction.