Tag Archives: TIM

Thermally Conductive Adhesive Tape

Top 3 questions customers ask when dealing with Thermally conductive adhesive tape for heat sinks.

The three most frequently asked questions about thermally conductive adhesive tape specifically made for heat sinks. This video covers how to apply the adhesive step-by-step for easy installation and removal.

Next, are the dimensions we carry for precise matching with your heat sinks. Finally, we go over the types and brands we carry. We only the best on the market from the companies who manufacture thermally conductive adhesive tape for heat sinks.

For more information on thermally conductive adhesive tape for heat sink please visit www.qats.com

Please don’t forget to watch our installation and removal video here: How to Remove Thermal Interface Material

Next Webinar: Thursday, July 18 @ 2pm ET

ATS Webinar

Don’t miss the next ATS webinar, “Using Thermal Interface Materials to Improve Heat Sink Thermal Performance”.

This is a free, pre-recorded webinar that will be held at 2pm ET on Thursday July 18th. Attendees will gain a much better understanding on what thermal interface materials are, how they function and how to best use them. The pros and cons of various thermal interface materials is also discussed. This class is from the perspective of the engineer who uses the material not one of the thermal interface material suppliers themselves.

There is no fee to attend, but virtual seating is limited so Register Now

Testing Thermal Interface Materials

Illustration: Parker Chomerics

Thermal interface materials, TIMs, provide the thermal pathway for transferring heat from components to heat sinks. At one time, most TIMs were simple, homogenous pads filled with thermally conductive fillers. But increasing power levels of processors and other components present a continuous need for improved thermal material performance. Today, a much wider range of TIMs is available, including phase change materials, compounds, and gap fillers.

When choosing a TIM, its essential to understand the testing methods to accurately determine the materials bulk thermal properties and in its performance.

The most common test is ASTM D5470: Linear Rod Method. This is the standard for measuring the thermal impedance of a TIM. Heat flow is carefully controlled through a test sample of a TIM. Typically, a heater is attached to an aluminum cylinder that has thermocouples arranged in series.

The thermocouples not only report temperature, but also the heat transfer through the known aluminum cylinder. Next, the interface material is compressed between the raised cylinder and an identical lower unit. Finally, a cold plate is attached to the bottom of the assembly to ensure the direction of heat transfer. The assembly can accommodate various material thicknesses and apply a range of pressure to the sample.

Another TIM test is laser flash diffusivity. Here, a small sample of interface material is subjected to a short pulse of laser energy. The temperature rise of the material is then recorded at a very high sample rate. Diffusivity is calculated using the equation shown below.

k = D/ρCp

Where:

k= thermal conductivity;

D = thermal diffusivity,

ρ = density of sample,

and Cp = specific heat.

The halftime of the sample is defined as the time between the start of the laser pulse to when the temperature of the back side of the sample has risen to half of its maximum value. The other variable in equation 1 is L, the thickness of the sample, which may be directly measured. Once diffusivity is known, it can be used in equation 2 to calculate thermal conductivity.

This laser flash method is very accurate as long as the density and specific heat are well known. However, it only measures thermal conductivity, as opposed to the ASTM standard which also measures thermal impedance. Thus, a key drawback to laser flash testing is that it doesn’t provide the contact resistance.

In comparisons of interface materials must be carried out by the user to provide meaningful results. Interface material testing procedures are different than heat sink testing methods. When testing several heat sinks it is possible to affix a thermocouple to the component’s case surface or to the heat sink itself and draw direct comparisons of performance. However, this approach will not work if the interface material is changed. To accurately compare interface materials, die-level temperature measurements must be taken, while the same heat sink is used in identical PCB and flow conditions.