From point of thermal performance, thermal gel provides excellent performance than thermal pad does. But some customers said performance of thermal gel failed to exceed that of thermal pad after testing. In practice, it may not happen like this. I deem that there are some points in application we missed. Take GLPOLY XK-GN30 for example, we analyse what is casusing the problem in application.

Firstly, applied thickness. Some customers didn’t notice the thickness applied, they just thought “more material we used, better performance we can get”. One of customers filled a 3mm gap with thermal gel, and found the performance is not as good as desired objective. From aspect of heat transfer, we recommend a thin bondline thickness as possible as we can desgin, thin and well distributed will expel air and fill small gaps, optimizing thermal performance.

Secondly, effective contact area. We should put some pressure when we assemble parts. Pressure will keep heat generator, thermal material and heat sink contact tightly, thermal gel is ultra conformable, it will fill gaps under low pressure, expelling air and decreasing contact thermal resistance. The effective contact area can be improved.

Thirdly, heat sink effectiveness. Most of people take notice of thermal interface materials, that’s good. Sometimes we need to pay attention to the heat sink. For example, one customer used 2.0W/mK of thermal material on power supply, it works good. But customer wanted to improve temperature rise and applied a thermal material with 5.0W/mK. All of us expect improved results, but in fact, it let us down. Two material provided a similar testing results. What’s the matter?  Thermal interface materials are verified by many customer, and flat and smooth interface makes contact effective,  there are no problem on these two factors.  The most likely possibility is heat sink, it reaches its limitation of effetiveness. It is verified our deduction by testing on a big heat sink.

We need to take all aspects into account and eliminate unfavorable factors, making thermal heat transfer effective.