Tag Archives: thermal interface material

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

The Monthly Qpedia is Out!

Qpedia_Aug13_coverThe monthly issue of Qpedia has just been released and can be downloaded at: http://www.qats.com/Qpedia-Thermal-eMagazine/Back-Issues.

This month’s featured articles include:

Application of TECs to Thermal Management of 3D ICs

From the thermal perspective, 3D stacked chips pose different challenges than what has been experienced in 2D packaging. For example, the heat dissipation of 3D ICs is highly non-uniform and multidirectional, due to the intrinsic chip architecture and the available real estate. When cooling at sub-ambient temperatures is necessary, the small footprint of a 3D chip becomes an impediment to deploying a cooling solution. Additionally, precision temperature control becomes difficult, since the surface to be controlled may be buried deep in the 3D stack. In response to cooling concerns about 3D ICs, this article presents a review of methods available for cooling 3D ICs to sub ambient temperatures using TECs.

Challenges in Testing Thermal Interface Materials

When choosing a thermal interface material (TIM), most of the time we look at the datasheet and find the thermal impedance if it is a solid material or the thermal conductivity if it is grease. Then, we calculate the thermal resistance and temperature rise with those numbers. But, how do we know that a TIM is performing as advertised? Can we really tell if one TIM will perform better than another, based on their specs? Additionally, the material presented in this article suggests that the data printed in TIM datasheets should be evaluated carefully to ensure that the testing procedures are similar to the actual application. Furthermore, even with the existing standards, many variables still exist.

Industry Developments: Portable Cooling Systems

Buildings and rooms constructed to house data centers are getting larger, more congested and warmer. Many of these structures have sophisticated thermal management systems featuring high-powered coolers or harnessing cold local water or air. For some needs, however, a portable cooling system can provide a much simpler and less costly solution. These systems can deliver direct cooling relief to equipment hot spots, and some can lower a room’s temperature when a central cooling system is inadequate or nonexistent.

Technology Review: Enhancing Heat Transfer on Surfaces

In this issue our spotlight is on enhancing heat transfer on surfaces. There is much discussion about its deployment in the electronics industry, and these patents show some of the salient features that are the focus of different inventors.

Cooling News featuring the latest product releases and buzz from around the electronics cooling industry.

Download the issue now and see why over 18,000 engineer’s subscribe to Qpedia. Click here to subscribe Subscribe to ATS

Don’t forget the Qpedia Book Series Promotion that coolingZONE is currently running! Save 25% off the hardcover books that are a must have in every engineer’s library!

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.

How To Video shows Best Ways to Remove Thermal Tape from Heat Sinks

In this Advanced Thermal Solutions “how to” video, we teach you how to remove three kinds of thermal interface material from a heat sink. Thermal Tape, Phase Change Material and Thermal Grease.

Should Engineers be Concerned with Thermal Grease Reliability in Electronics Cooling?

In our Qpedia Thermal eMagazine we reported on whether or not thermal grease is a reliable thermal interface material. When thermal greases are operated for an extended length of time the thermal interface resistance can actually increase. The degradation mechanisms of greases are considerably different and more complicated to characterize than other thermal interface solutions. In this article we explore the failure mechanisms of grease interface layers as well as reliability testing and results.

To read this Qpedia Thermal eJournal article in full, just click to this link: Long Term Thermal Grease Reliability

To learn more about thermal interface material, join our free webinar on “Understanding and Choosing the Best Thermal Interface Materials to Improve Heat Sink Thermal Performance“, Thursday, November 17th, 2PM