Thermal grease, also known as thermal conductive grease, thermal paste, or thermal compound, etc., is used to create a thermally conductive layer between the processor and the heat sink. Thermal grease is the link between the cpu and the radiator for heat transfer. It also acts as a heat transfer medium, increases the contact area, buffers vibration and pressure, and fills the pits between the radiator and the cpu. Since thermal grease conducts heat better than air, applying thermal grease between the processor and the heat sink can enhance heat transfer from the processor to the heat sink.
After the influence of the thickness of silicone grease on heat dissipation, the CPU temperature fluctuates between 61-62°C when applying an appropriate amount of silicone grease, and the CPU temperature fluctuates between 63-64°C when a large amount of silicone grease is applied. It can be found that the thickness of the silicone grease layer has an obvious effect on heat dissipation. From this test, there is a 2°C gap between the two.
Therefore, the correct application of thermal grease has a multiplier effect on the heat dissipation of the cpu. Too much or too thick thermal grease is equivalent to adding a heat-conducting medium, which affects the heat transfer of the cpu to the radiator (the heat of the thermal grease the resistance is larger than the thermal resistance of metal), and excess heat dissipation silicone grease will even flow into the CPU socket. Although the current silicone grease is generally insulating and will not cause a short circuit, it flows to the metal contacts of the CPU and the socket. It is easy to cause a short circuit between the cpu pins. In the light of the computer can not be started, in severe cases, it will cause damage to the cpu or other peripheral hardware; too little or uneven application of thermal grease will cause no gap between the cpu and the radiator. The medium of buffering and heat conduction reduces the contact area between the CPU and the heat sink in disguised form, resulting in a decrease in heat dissipation efficiency.
Process plan for applying thermal grease
- First clean the surface of the CPU core and the bottom of the heat sink with a high-purity solvent (such as high-purity isoamyl alcohol or acetone) and a lint-free cloth (such as a camera lens cloth), taking care not to let your fingers touch the surface of the core and heat sink.
- Determine the area on the heat sink that is in contact with the CPU, and apply an appropriate amount of thermal grease on the CPU. At this time, you can ignore its uniformity, coverage and thickness.
- Prepare a moderately soft and hard plastic scraper (or cardboard), spread the thermal grease, and use the scraper to scrape in one direction at an angle of about 45 degrees, so that the thermal grease is evenly formed on the entire surface of the CPU. thin layer.
- Apply a small amount of thermal grease to the bottom of the radiator. Similarly, using the method we just applied to the CPU, apply the thermal grease to an area as large as the CPU shell. The purpose of this step is to make the particles in the thermal grease fully Fill the uneven grooves on the bottom of the radiator to make sure that there are no foreign objects on the surface of the radiator base and the CPU core, then install the radiator on the cpu, and fasten the fasteners.
Matters needing attention after applying thermal grease
- The heat-dissipating silicone grease will never be cured after being applied. It should be noted that if the heat-dissipating silicone grease is cured, this heat-dissipating silicone grease is unqualified and cannot be used in industrial manufacturing in large quantities. When buying, you need to pay attention. In order to avoid this situation, users can buy products with word-of-mouth guarantee, which can reduce the chance of this situation. For example, Nuofeng Electronics nfion, which focuses on the R&D and customized production of heat-dissipating silicone grease, can provide different customized solutions.
- Apply evenly: For the bottom surface of an ordinary radiator, the thickness of thermal grease applied is about the thickness of a piece of paper. After the thermal grease is applied, place the heat sink on the CPU. At this time, it can only be pressed lightly, and the heat sink cannot be rotated or translated. Otherwise, the thickness of the thermal grease between the heat sink and the CPU may be uneven.
- It is necessary to observe whether there are air bubbles after applying the heat-dissipating silicone grease. If there are air bubbles, they can be punctured with a toothpick. Otherwise, these air bubbles will cause uneven application. In addition, there will be air in the air bubbles, which will also increase the thermal resistance and affect heat dissipation. Effect.
- The remaining heat dissipation silicone grease needs to be sealed and can be placed in a cool place, so that it can be used up within 12 months. After more than 12 months, the thermal conductivity will decrease and cannot be used again.
Thermal grease is a thermally conductive material with good heat dissipation performance. Thermal grease can be used in various electrical appliances or electronics. There is no change in performance before and after use, and it is always in the state of grease. Thermal grease can only be smeared in the middle of the heating element of the electrical appliance and the heat dissipation facility. Only by mastering the correct operation method when smearing can achieve the purpose of heat dissipation.