CPU Cooler’s main Part-the Heatsink

Materials for air-cooled radiators

In fact, silver is the best conductive medium, but its metal is very soft, which is not conducive to the manufacture of high-density metal objects such as radiators. The precious metal gold also has a good conductivity coefficient, but its expensive “price” is not one of the metals considered by radiator manufacturers. Of course, soft silver can be made into high-end thermal grease (for example: Arctic Silver series is this type of thermal grease, but the value is also not cheap). Therefore, the manufacturing materials of air-cooled radiators are only copper, aluminum and aluminum alloy are the materials of choice for mainstream radiators today. Manufacturing


process of air-cooled radiators



The current manufacturing process of CPU radiators has always been a must-consider for consumers when purchasing CPU radiators. Because the better the manufacturing process, the higher the performance of the CPU radiator, which is impeccable. With the increase of CPU frequency, many manufacturing processes have gradually left our sight. At present, our domestic heat sinks mostly use extrusion technology, folding technology, reflow soldering technology and heat pipe technology.

Extrusion process (aluminum profile process)


Extrusion process (aluminum profile process), since the history of extrusion process of CPU heat sink is very long (the first CPU heat sink also adopts extrusion process), it has been developed for 10 years. And now more than half of the heat sinks (including heat sinks in all industries) adopt extrusion process, so the extrusion process seems to be quite mature. Moreover, the processing requirements of aluminum are relatively simple, and the density of aluminum is relatively low. Its unit weight is relatively light, which is very suitable for making some mainstream heat sink devices, and it is also widely used in a wide range of industries. The

advantage of extrusion technology is that the molding is relatively mature and the cost is relatively low. However, its shortcomings are gradually exposed as the CPU frequency continues to increase. Because the density of aluminum sheets is relatively low, when the heat is too high, the air volume and the heat dissipation area need to be increased, which is undoubtedly a challenge to noise and area. Therefore, in the future mainstream heat sinks, perhaps after a period of time, the CPU heat sink using extrusion process will become history.

Folding leaf process


The folding leaf process is based on the use of metal folding. This process is actually very similar to the sunflower type. This process allows the effective heat dissipation area to increase with the leaves. The more leaves and the denser the process, the higher the heat dissipation area. The folding leaf process is more complicated than the previous extrusion technology, because many manufacturers do not do a good job of making the metal folding leaf and the bottom contact tightly. There is also a pressing problem involved. If the pressing technology cannot be successfully supported, the performance of the radiator will not pass the test, so general manufacturers will not be able to manufacture it, and the weight cannot be controlled. Therefore, the folding leaf process is generally used on high-end radiators.

Reflow Soldering Process


The reflow soldering process is generally used on heat sinks made of copper. The principle is to make thin copper sheets into fins and connect them well to the base. This principle is the welding technology. However, welding technology can no longer meet the needs of today’s fine all-copper heat sinks. Therefore, a novel reflow soldering technology has become a necessary process for manufacturing precision heat sinks today. In summary, reflow soldering is to accurately set the temperature and time parameters of soldering through a computer so that the solder paste and the metal being soldered are in full contact. The application of this technology ensures the excellent heat dissipation performance of pure copper heat sinks.

Heat pipe technology


Heat pipe technology, heat pipes are generally hollow cylindrical tubes, part of which is filled with liquid that is easy to evaporate. The tube is always kept in a vacuum state, and the evaporation temperature of the liquid in it is close to the ambient temperature. When the heat is absorbed by the volatile layer, the liquid is quickly heated to the boiling point, and then begins to boil, producing steam, which rises to the cooling layer. When the heat is released, the steam condenses into droplets again. Due to gravity or other internal effects, the droplets return to the volatile layer, continue to evaporate, and then are cooled, forming a repetitive cycle. The heat source is what drives this cycle, which is the principle of the heat pipe technology.

Ceramic Craft

The production process of ceramic technology is basically the same as that of kiln furniture. Thermal conductivity and anti-oxidation performance are the main application properties of the material. Its principle is to place the ceramic radiator in a place close to the flue outlet and at a higher temperature. It does not need to be mixed with cold air or high temperature protection. When the kiln temperature is 1250-1450℃, the temperature of the flue outlet should be 1000-1300℃. The ceramic heat exchanger can recover waste heat up to 450-750℃. The recovered hot air is sent into the kiln to form a mixed gas with the gas for combustion, which can reduce production costs and increase economic benefits.

Ceramic heat exchangers have been well developed under the limitations of metal heat exchangers because they have better solved the problems of corrosion resistance and high temperature resistance, and have become the best heat exchanger for recovering high-temperature waste heat. After years of production practice, the results show that ceramic heat exchangers are very effective. Its main advantages are: good thermal conductivity, high high-temperature strength, good oxidation resistance and thermal shock resistance, long life, low maintenance, reliable and stable performance, and easy operation. It is currently the best device for recovering high-temperature flue gas waste heat.

Manufacturing process of air-cooled radiator

Forging process (cold forging)

Forging process (cold forging), the forging process is to press the metal into a forging die with high pressure under a special physical state (yielded state), and pre-place a copper block on the die and insert it into the yielded aluminum. Due to the special properties of aluminum in the yielded state (non-liquid, soft, and easy to process), copper and aluminum can be perfectly combined to achieve no gap in the middle and very low interface thermal resistance. The forging process is difficult and costly, so the finished product is expensive and belongs to a non-mainstream product. Heat sinks using this process generally have many densely packed needle-shaped fins. The heat sinks manufactured by this process are rich in style and have a large design imagination space, but the cost is also relatively high.

Crimped Fin


Crimped Fin, the crimping process boldly improves the traditional copper-aluminum bonding technology. First, the copper plate is planed into fine grooves, and then the aluminum sheet is inserted. The aluminum sheet is combined with the base of the copper sheet using a pressure of more than 60 tons, and no medium is used between the aluminum and the copper. From a microscopic point of view, the atoms of the aluminum and copper are connected to each other to a certain extent, thus completely avoiding the disadvantage of the traditional copper-aluminum bonding that produces interface thermal resistance, greatly improving the thermal conductivity of the product, and can produce various process products such as copper sheet inserted into aluminum seat, copper sheet inserted into copper seat, etc., to meet different heat dissipation needs. This technology has significantly extended the life of some copper-aluminum bonding technologies.

In addition to the above, there are some other copper-aluminum bonding methods, but the process mainly ensures the bonding quality of the thermal contact surface of copper and aluminum, otherwise the heat dissipation effect is not as good as that of all-aluminum alloy heat sinks. The new process needs to be continuously verified and improved to achieve the expected effect. When choosing a copper-aluminum combined radiator, you must not only look at the appearance. Only by actual comparison can you buy a high-quality copper-aluminum combined radiator.

Compression process

The pressing process is to fix dozens of heat sink fins with exactly the same appearance together, and then drill holes in the bottom and thread them together with a bolt; then the screws are tightened by a machine. Since it is as tight as possible (the tighter the better the thermal conductivity and heat dissipation), there are also manufacturing machines such as the radiator universal pressing machine; and the last step is to polish the bottom surface, and the whole process is completed after it is polished and flat.

Core contact technology (heat pipe) is the contact management between the heat source and the heat sink. In terms of CPU cooling, initially it was simply to press the heat sink components and the CPU together. As the demand for CPU cooling continues to increase, the heat dissipation capacity of the heat sink components has been challenged. This core contact technology (heat pipe) realizes direct contact between the heat pipe and the CPU, so that the heat from the heat source can be directly transferred to the heat sink fins with the help of the extremely strong heat transfer capacity of the heat pipe, thereby maximizing the heat dissipation efficiency of the radiator.

In fact, there are more manufacturing processes for the heat sinks in CPU coolers, adding up to dozens of them, so I won’t list them in detail one by one. The main popular manufacturing processes that are currently used more frequently are extrusion (aluminum profile) process, pressing process, core contact technology (heat pipe), and heat pipe (reflow soldering) process.

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