| Thermal Conductivity | Select a grade according to the application: approximately 1–3 W/m·K for general heat transfer, 3–8 W/m·K for higher-performance assemblies, and above 8 W/m·K for specialty applications. | Higher conductivity can improve heat spreading, but the final result also depends on bond-line thickness, contact pressure, and surface flatness. | Recent test report stating the test method, specimen preparation, temperature, and uncertainty. ASTM D5470 or ISO 22007-2 methods may be relevant. | 20% |
| Thermal Impedance at Actual Thickness | Require thermal resistance data at the intended application thickness, such as 0.5 mm, 1.0 mm, or 2.0 mm, rather than relying only on conductivity. | Thermal impedance directly reflects heat-transfer performance in the assembled product and can expose differences between laboratory and production conditions. | Application-specific thermal resistance curves, test conditions, and results at the expected compression or mounting pressure. | 15% |
| Dispensing and Processability | Material should dispense consistently through the selected manual, pneumatic, or automated equipment without excessive stringing, clogging, settling, or air entrapment. | Stable processing reduces material waste, assembly defects, operator variation, and downtime. | Viscosity or rheology curve, recommended nozzle size, pressure range, dispensing speed, and practical line-trial results. | 12% |
| Compression and Gap-Filling Capability | Material should fill the specified gap range while maintaining contact with uneven surfaces and avoiding excessive squeeze-out during assembly. | Thermal putty is commonly selected for irregular gaps, component-height variation, and applications where conventional pads are difficult to fit. | Recommended minimum and maximum gap, compression-force data, dispense pattern, and assembly trial results. | 10% |
| Reliability and Aging Stability | Require evidence of thermal cycling, high-temperature storage, humidity exposure, and pump-out or dry-out resistance appropriate to the product environment. | A material that performs well initially may fail if it migrates, dries, cracks, or loses contact during long-term operation. | Reliability test plans, before-and-after thermal data, photographs of the interface, and defined acceptance criteria. | 12% |
| Electrical and Regulatory Compliance | Confirm whether the product is electrically insulating or electrically conductive, then match the requirement to the design. Compliance documentation should address applicable RoHS and REACH obligations. | Electrical behavior and restricted-substance status can affect product safety, certification, export, and material approval. | Volume or surface resistivity data where applicable, safety documentation, RoHS declaration, REACH statement, and relevant flammability information. | 10% |
| Batch-to-Batch Consistency | Key characteristics such as conductivity, viscosity, density, color, and work life should remain within documented production limits. | Consistent batches make process qualification, inventory control, and mass production more predictable. | Certificate of analysis for multiple batches, control limits, lot traceability, and quality-management certification such as ISO 9001 where available. | 8% |
| Customization and Engineering Support | Supplier should be able to adjust conductivity, softness, rheology, electrical properties, packaging, and dispensing format when the standard grade is unsuitable. | A technically capable supplier can shorten development cycles and improve compatibility with the customer’s assembly process. | Technical data sheets, sample-development procedure, design-of-experiment support, and documented change-control process. | 5% |
| Packaging, Shelf Life, and Storage | Typical shelf-life claims often fall around 12–24 months, but the approved value must come from the supplier’s product specification and storage conditions. | Correct packaging and storage control help prevent premature curing, contamination, moisture exposure, and material waste. | Shelf-life statement, storage-temperature range, packaging options, lot/date coding, and transport-condition guidance. | 4% |
| Lead Time, Capacity, and Technical Response | Supplier should provide a documented sample-to-mass-production process, realistic lead-time commitments, production-capacity information, and defined response times for quality issues. | Reliable delivery and fast technical communication reduce launch risk and protect production continuity. | Sample lead time, production lead time, minimum order quantity, capacity statement, escalation contact, and corrective-action records. | 4% |