Posted on 25 June 2012

Measurement of Thermal Paste

Wet Film Thickness Gauge for Measurement of Thermal Paste








How to correctly measure the thickness of thermal paste

Put the Wet Film Thickness Gauge vertically on the surface of the thermal paste without
moving it horizontally. Press slightly and remove.

Wet film thickness gauge is pressed into thermal paste

Visually inspect the marks on the thickness gauge. The thickness of the thermal paste is between the value at the highest visible mark and the next higher value on the gauge (where no mark is present).

In the left orange circle, there is a slight mark on the thickness gauge left by the thermal paste. In the right circle, there is no mark. Therefore, the measurement result is in between 0,050 – 0,075mm.

Inspect thermal paste marks on wet film thickness gauge

For Power Electronic Devices, the thickness layer usually lies between 0,05 – 0,2mm. Please consult the data sheets of your manufacturer for the exact measures.


For more information, please read:

Thermal Paste Application


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2 Responses

  1. avatar fail says:

    this is complete nonsence, the tool relies on the underlying surface being consistently flat across the whole measurement surface.

    Then the pase also has to be a unifim thickness across the surface.


    What a massive fail.....

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    • avatar PowerDahl says:

      Thermal paste thickness measurements are taken for quality control purposes. The reason is that there is an optimal thickness for the paste depending on the application.

      You are correct that the reliability of the measurement relies on the uniformity of the surface and the paste layer, which are other issues that must be addressed to achieve a suitable thermal interface. This certainly does not imply that a measurement of thermal paste thickness is "nonsense" as you suggest. For example, the interface surfaces and paste thickness could be extremely uniform, but this would not matter if the paste thickness was much too thin or much to thick.

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