People know that thermal conductivity and thermal impedance are vital factors to thermal performance of thermal gap pad, but they ignor another significant factor which has great impact on thermal performance—hardness.

For silicone based thermal gap pad, we usually use Shore00 test standard, tolerance is +/-5. Maybe readers don’t have a concept how it affects thermal performance if they are not in thermal management field. For example, if the hardness is lower, the thermal pad is softer. It will offers more excellent compliancy, making thermal pad expelling air gap and optimizing thermal transfer.

Theoretically, for thermal gap pad, the softer the better. But we need to consider something else, such as transport, handle and assembly. If thermal pad is too soft, it is easily destroyed when workers assemble them. GLPOLY study lots of applications and find that hardness shore00 35-55 is suitable for most of electronics thermal solution, except thermal transfer, it can works as a vibration dampening cushion and protect the components.