Shengyi S1000 PCB: Mid-Tg FR-4 Data and Stackup Review

Read S1000 thermal data as separate measurements

The cited official product page reports typical Tg of 155°C by DSC, Td of 335°C at a 5% mass-loss criterion, and integrated Z-axis expansion of 3.4% over 50–260°C. These measurements describe different responses. Tg concerns a transition in the polymer system; Td concerns decomposition under a specified test; integrated expansion describes dimensional change over a temperature interval.

None is a continuous operating-temperature limit. Do not use a favorable Tg to justify an arbitrary soldering profile or assume that it prevents component overheating. The board's copper, thermal paths, hole construction and assembly history still matter. Retain the original specimen and method notes when translating the data into project requirements.

Source-qualified material review

Establish the stackup before discussing replacement

A material order should identify the laminate, matching bonding material, cured core thicknesses, copper foil and intended pressed dielectric intervals. An overall 1.6 mm board can contain many different internal constructions. Two suppliers can quote the same nominal board thickness while proposing different glass styles and resin distributions.

Ask for the proposed stackup alongside the material identity. Mark controlled-impedance layers, heavy copper regions and significant thermal exposures. If the proposed change is to S1000-2, compare the complete construction and required evidence; a higher temperature headline alone does not establish a drop-in replacement.

Keep low-frequency Dk out of an unverified RF model

The official page's Dk 4.9 and Df 0.011 are associated with 1 MHz data. They should not be inserted into a GHz channel calculation simply because they are easy to find. Frequency, test fixture, conditioning and resin content can change the interpretation of electrical data.

For a digital board, ask which design value and construction the field solver uses. For a loss-sensitive route, compare complete line attenuation including copper and transitions. If no relevant electrical data is available, record that gap before fixing trace geometry. A calculation with precise decimals cannot repair an unsupported material input.

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 thickness expansion to frame the via discussion

The engineering worksheet integrates two entered CTE values around an idealized transition. Its default values are hypothetical and are not a built-in S1000 profile. With 1.6 mm thickness, a 25–200°C excursion, a 150°C transition, and 50/250 ppm/°C coefficients, the free thickness change is 30 µm. That example is useful for checking units, not predicting plated-hole life.

Copper barrels constrain the laminate, while actual transitions are distributed rather than perfectly sharp. Plating quality, hole aspect ratio, copper thickness and repeated exposure need their own review. Supply the full heating history and hole architecture when asking whether a construction is appropriate.

Make the cost comparison on equal terms

A lower laminate purchase price does not necessarily reduce the accepted-board cost. Panel utilization, layer structure, process allowances and agreed testing can change the comparison. Separate one-time tooling from recurring board and inspection allowances. Enter only values supported by your quote or clearly labeled internal assumptions in the optional budget tool.

If the comparison involves S1141 conventional FR-4, check its explicit application exclusions as well as cost. If halogen composition is a fixed customer requirement, examine a documented route such as S1150G rather than assuming lead-free compatibility proves halogen-free composition.

Prepare an answerable S1000 inquiry

Send the drawing revision, stackup, dimensions, quantity, finished copper, surface finish and relevant assembly exposures. State whether the exact grade is mandatory or whether alternatives can be reviewed. Include the electrical test conditions and required material records, especially for a repeat program.

A useful response should identify the proposed material and construction, open exceptions and the evidence needed before release. Keep the approved answer with the fabrication package. The source values on this page support screening; current availability, supplied-lot requirements and manufacturing suitability still need confirmation for the actual order.

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.