{"id":10050,"date":"2019-04-23T09:53:32","date_gmt":"2019-04-23T13:53:32","guid":{"rendered":"http:\/\/www.qats.com\/cms\/?p=10050"},"modified":"2019-04-23T09:53:36","modified_gmt":"2019-04-23T13:53:36","slug":"engineering-how-to-removing-thermal-interface-materials","status":"publish","type":"post","link":"https:\/\/www.qats.com\/cms\/2019\/04\/23\/engineering-how-to-removing-thermal-interface-materials\/","title":{"rendered":"Engineering How-To: Removing Thermal Interface Materials"},"content":{"rendered":"\n

By Norman Quesnel<\/strong>
Senior Member of Marketing Staff
Advanced Thermal Solutions, Inc. (ATS)<\/a><\/em><\/p>\n\n\n\n

As you may already know, TIMs \u2013 thermal interface materials \u2013 are not especially easy to remove from heat sinks. But the needs to do so are common: repositioning the sink, switching to a better performing TIM, replacing components, etc. <\/p>\n\n\n\n

Most of today\u2019s TIMs are bonded to\nheat sink surfaces with a pressure-sensitive adhesive layer. The rest of the\nTIM may be an elastomer filled with thermally conductive particles. Bonding\npressure, such as from clips and screws increase the thermal performance, but\nthe result can be a TIM that\u2019s hard to remove from the heat sink surface. <\/p>\n\n\n\n

Another kind of TIM is thermal grease,\nwhich is an excellent heat conductor but is inherently messy. This must be\naccounted for when removing thermal grease from a heat sink surface.<\/p>\n\n\n\n

With the right tools and some\npatience, a heat sink can have its TIM removed completely. The approaches are\nsimilar for removing different kinds of TIMs. <\/p>\n\n\n\n

Removing\nThermal Tapes<\/strong><\/p>\n\n\n\n

\"Removing<\/figure>\n\n\n\n

Double-sided thermal interface tapes\nprovide exceptional bonding properties between components and heat sinks. For\nmany applications they remove the need for mechanical fasteners to secure the\nsink to the component. <\/p>\n\n\n\n

Here we are showing the removal of\nParker Chomerics Thermattach T412 tape from a heat sink. The T412 tape has\naluminum mesh carrier which helps improve heat transfer. The aluminum also\nhelps keep the TIM together when it\u2019s removed.<\/p>\n\n\n\n

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Use a razor blade, but don\u2019t gouge the\naluminum because if it makes the surface uneven that will negatively impact\nheat transfer. Start at one corner, try to lift the TIM slightly the razor\nblade, be careful not to cut yourself. <\/p>\n\n\n\n

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Next, put the heat sink (upside down)\non a paper towel. This is mainly to protect the fins of the heat sink from getting\nscraped. Then, use a putty knife with a flexible blade, or a plastic scraper or\nsomething similar with a non-gouging edge to help remove the rest of the TIM. <\/p>\n\n\n\n

Push the scraping edge carefully\nforward under the TIM corner, while pulling the TIM slightly up. While you are\nstarting to lift the original TIM corner from the surface, you can start doing\nthe same on another corner. And if continue to work at it from different angles\neventually you can get the TIM off. <\/p>\n\n\n\n

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If there is TIM residue left over on\nthe heat sink surface, you can use a lint-free cloth and a solvent to wipe it\nclean. The solvent should be something that won\u2019t damage the finish on the heat\nsink. Here we used isopropyl alcohol. You may have to repeat this several times\nto get everything off and you have a clean surface.<\/p>\n\n\n\n

Removing Phase-Change Materials <\/strong><\/p>\n\n\n\n

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Phase-change materials (PCM) can be removed with similar steps as with thermal tapes. These images show the removal process using a maxiFLOW™ push pin heat sink from Advanced Thermal Solutions, Inc. (ATS).<\/p>\n\n\n\n

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Start with sharp, clean razor blade\nbecause a plastic scraper\u2019s edge isn\u2019t fine enough to penetrate cleanly under\nthe TIM. Be sure the razor blade is straight to minimize the risks of nicks to\nthe heat sink surface. The TIM manufacturer\u2019s data sheet recommends using a\nrazor blade to remove the phase change TIM. In this demo, the TIM is Chomerics\nT766 PCM. Slowly work the razor blade edge under the TIM, be careful of your\nfingers. <\/p>\n\n\n\n

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After a lot of use phase change\nmaterials can be hard to remove compared to new pieces. Use the razor under different\ncorners. Go slowly until you get all the material off. You will be left with some\nPCM residue on the heat sink surface. <\/p>\n\n\n\n

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You can put a small amount of\nisopropyl alcohol on the surface and use this as a lubricant and go back with\nthe razor blade to get a close shave on that surface to remove much of the remaining\nTIM residue. <\/p>\n\n\n\n

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When your sink\u2019s surface is nearly\nclean, get a lint free cloth or a wipe. With some alcohol and with a bit of\nrubbing you should be able to remove the rest of the phase change material.<\/p>\n\n\n\n

Removing\nThermal Grease<\/strong><\/p>\n\n\n\n

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Here we start with a heat sink with\nthermal grease on its mounting surface. <\/p>\n\n\n\n

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Start by removing as much grease as possible\nusing a dry cloth or paper towel. You should be able to get most of the grease\noff this way. <\/p>\n\n\n\n

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Then, for the leftover grease residue,\nuse a lint-free cloth or rag with some alcohol or another type of solvent that\nwon\u2019t eat away at the heat sink\u2019s anodized surface. With a little elbow grease,\nyou should be able to get the surface clean.<\/p>\n\n\n\n

Note that If you\u2019re going to be doing a lot of handling of thermal greases and solvents, it\u2019s advisable to wear protective gloves.<\/p>\n\n\n\n