Effects of hardness of thermal pad on thermal performance

Most people know that thermal conductivity and thermal impedance are vital factors to thermal performance, but they ignor another important factor which has great impact on thermal performance—hardness.

For Silicone thermal gap pad, we usually use Shore00 test standard, tolerance is +/-5. Maybe readers don’t have a concept how it effects thermal performance. If the hardness is lower, the thermal pad is more softer. It offers more excellent compliancy, this will make 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.