| Circuit function | Signal, power, sensor, keypad, LED, or other application; operating voltage and current. | List the electrical loads and required connections. Current capacity depends on conductor width, copper thickness, temperature rise, and heat dissipation. | Ask for design-rule review, current-carrying guidance, and any needed thermal or voltage-drop assessment. |
| PET film and thickness | PET grade, film thickness, color, surface finish, and any transparency requirement. | PET film thickness is commonly selected from material and application needs; approximately 0.05–0.25 mm is a useful early design range, not a universal limit. | Confirm available film grades, thickness tolerances, dielectric data, and suitability for the expected temperature and environment. |
| Conductor material and thickness | Copper, printed conductive ink, or another conductor; thickness or specified sheet resistance. | Copper thickness affects resistance, flexibility, and fabrication. Printed conductors may be suitable for some low-current designs but have different resistance and process characteristics. | Request the proposed conductor construction, resistance data, adhesion information, and process capability for the chosen material. |
| Trace and spacing rules | Minimum and nominal trace width, spacing, tolerances, and any controlled-impedance requirement. | Set rules from electrical needs and the selected manufacturing process. Fine-line capability varies by conductor type, thickness, and production method. | Have the supplier review the CAD data and confirm achievable line/space dimensions and relevant inspection methods before release. |
| Layer count and construction | Single-sided or double-sided circuit, insulation layers, coverlay or overcoat, and exposed contact areas. | A simpler construction can reduce process complexity. Double-sided designs may require additional alignment, insulation, and interconnection considerations. | Request a proposed layer stack-up, material specifications, and details of how vias or layer-to-layer connections are made, if required. |
| Bend and flex conditions | Static bend or repeated flexing, bend radius, direction, cycle count, and locations of bends relative to traces. | Repeated flexing generally requires more conservative material and layout choices than a one-time installation bend. Avoid placing sharp corners or stress points in bend zones. | Confirm that the proposed construction is suitable for the stated bend radius and cycle target; request test evidence when flex life is critical. |
| Connectors and contacts | Connector type, contact pitch, contact dimensions, insertion requirements, and contact finish. | Define the mating component and mechanical tolerances early. Contact finish and exposed-pad design should match the connection method and expected use. | Verify contact dimensions, finish, alignment tolerances, and compatibility with the intended connector or assembly process. |
| Environmental conditions | Operating and storage temperatures, humidity, UV exposure, chemicals, abrasion, and expected service life. | PET properties and adhesive or coating performance vary by grade and construction. Specify the actual exposure conditions rather than relying on a generic material label. | Request relevant material data and, where needed, qualification testing against the defined environment and acceptance criteria. |
| Outline and tolerances | Overall dimensions, cutout locations, edge tolerances, registration needs, and panelization requirements. | Include critical-to-fit dimensions and identify datums. Tolerances should reflect the actual assembly interface and manufacturing process. | Ask for a capability review of critical dimensions and confirm the measurement method and inspection sampling plan. |
| Quality and testing | Electrical continuity, isolation, visual criteria, dimensional inspection, adhesion, and any application-specific tests. | Define pass/fail limits and test coverage before quotation. Testing should correspond to the design risks and the product's intended use. | Confirm available test equipment, inspection records, traceability options, and how nonconforming parts are handled. |
| Volume and lifecycle | Prototype quantity, annual demand, batch size, forecast, and expected product lifecycle. | Tooling, panelization, and process choices can differ between prototypes and production. Provide realistic forecasts to support planning and cost estimates. | Request separate prototype and production quotations, lead-time assumptions, tooling details, and change-control expectations. |
| Design files and documentation | Gerber or other fabrication files, drill data if applicable, stack-up, outline, drawings, BOM, and revision level. | Keep file revisions aligned and include notes for critical features, test requirements, and assembly interfaces. A drawing can clarify requirements not captured in artwork. | Confirm the supplier's preferred file formats, data-check process, and approval workflow before manufacturing starts. |