Why Your Thermal Grease is Failing: Understanding Pump-Out and How Phase Change Materials Prevent It
Are you seeing a gradual rise in operating temperatures or unexpected shutdowns in your fielded products? The culprit might not be your heatsink or fan, but the thermal grease itself. A common and often overlooked failure mode is “pump-out” – where thermal compound is physically pumped away from the interface during repeated power cycling.
Why does pump-out happen? As components heat up and cool down, materials expand and contract at different rates. This microscopic motion can slowly push viscous greases to the edges, leaving the central hotspot with inadequate coverage. Combined with dry-out from high-temperature exposure, this leads to increased thermal resistance and, ultimately, overheating.
So, what’s the alternative for mission-critical or long-lifecycle designs? Enter Phase Change Thermal Interface Materials.
Unlike grease, a phase change thermal pad like the SP180 is solid at room temperature during assembly. When it reaches its designed activation temperature, it softens to perfectly fill gaps. Crucially, upon cooling, it resolidifies in place. This eliminates the pump-out mechanism entirely, locking the material exactly where it’s needed.
Key advantages for reliability-focused designs:
- Consistent Performance: Maintains low thermal resistance over thousands of temperature cycles.
- Process Control: Solid pre-form ensures the correct amount of material is applied every time, unlike manual grease dispensing.
- Cleanliness: No risk of grease contamination on sensitive components or connectors.
If you’re troubleshooting thermal interface degradation or designing a product where maintenance is impossible, switching to a non-pump-out solution is a wise engineering decision. Explore the reliability data of our non-pump-out thermal interface solution, the SP180 Phase Change Pad, to secure your design’s thermal performance for its entire lifespan.
