On a design we have in production, we have an Apalis iMX8 module assembled onto the board using the recommendations found in chapter 4 of the Apalis Carrier Board Design Guide. We use the Toradex heatsink for the Apalis iMX8 and have a thermal/mechanical standoff mounted at the center of the module as recommended.
We’ve found that the thermal standoff does not always make a good thermal connection to the module, resulting in widely varying operating temperatures of our final assemblies.
Do you have a recommendation for a thermal material that could be applied to the top of the standoff to improve the thermal conduction?
I asked our team internally if they have any good recommendations and, if they have, I will post the answer here.
Despite that, are you using an air cooler with the heat sink or only the heat sink?
Yes, we have a PWM fan mounted to the heatsink. We found that the assemblies required quite different fan PWMs in order to maintain a consistent operating temperature (eg, 40% for some modules, 80% for others).
In order to reduce the fan noise, we would like to operate in the 40% region. We tried using a cut-down gap filler on the standoff of one of the assemblies and saw a reduction from around 60% PWM to 40% PWM. We are hoping to find a standard or recommended solution to avoid hand-forming a custom solution for each assembly.