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Aluminum Heat Sink & Profile Manufacturing

address:No. 51 Luming Road Heavy River Management District - Qing Town Dongguan City

Q Q:2131405854

Telephone:+86 13827205356

mailbox:cnc@cncstamping.com

Heat sink (radiator) manufacturing and molding technology

time:2021-01-13 15:22 author:Heat sink design click:

The mainstream forming technologies for heat sinks mostly fall into the following categories: aluminum extrusion technology, aluminum die-casting technology, combined heat sink manufacturing process, and forging process. The processing technology of the heat sink determines the final performance of the heat sink. It is also the most important embodiment of the manufacturer's technical strength.

Aluminum extrusion technology for heat sink
Aluminum extrusion technology (Extruded)
Simply put, the aluminum extrusion technology is to heat the aluminum ingot to a high temperature of about 520~540℃, and let the aluminum liquid flow through the grooved extrusion die under high pressure to make the preliminary heat sink. Then the original embryo of the heat sink is cut to form the fins we commonly see. Aluminum extrusion technology is easy to implement, and the equipment cost is relatively low, which has also made it widely used in the low-end market in the previous years. The commonly used aluminum extrusion material AA6063 has good thermal conductivity (about 160~180 W/m.K) and processability. However, due to the limitation of its own material, the ratio of the thickness to the length of the heat dissipation fins cannot exceed 1:18, so it is difficult to increase the heat dissipation area in a limited space. Therefore, the heat dissipation effect of the aluminum extruded heat sink is relatively poor, and it is difficult to be qualified for the high-frequency CPU that is rising today.

Aluminum die casting technology for heat sink
Aluminum die casting technology
In addition to aluminum extrusion technology, another process that is often used to make heat sinks is aluminum die casting. After the aluminum ingot is melted into a liquid state, it is filled into a metal mold, and directly die-casted by a die-casting machine to form a heat sink. The fins can be made into a variety of three-dimensional shapes by injection molding. The heat sink can be made into a complex shape according to requirements, and it can also be made into a heat sink with a guiding effect according to the fan and the airflow direction, and thin and dense fins can be made to increase the heat dissipation area. Because of its simple process, it is widely used. The commonly used die-cast aluminum alloy is ADC12, which is suitable for thin castings due to its good die-casting formability. However, due to the poor thermal conductivity (about 96 W/m.K), AA1070 aluminum is mostly used as die-casting material in China, and its thermal conductivity is as high as about 200 W/m.K, which has a good heat dissipation effect.
However, AA1070 aluminum alloy die-casting radiator has some inherent shortcomings that it cannot overcome by itself:
(1) Excessive surface flow lines and oxide slag during die casting will reduce the heat transfer effect.
(2) When cooling, the internal micro-shrinkage holes are higher, and the actual thermal conductivity is reduced (K<200 W/m.K).
(3) The mold is easily corroded, resulting in a short life.
(4) Poor formability, not suitable for thin castings.
(5) The material is soft and easily deformed.
With the continuous improvement of CPU frequency, in order to achieve better heat dissipation effect, the volume of aluminum radiators produced by die-casting technology has been increasing, which has brought many problems to the installation of radiators. In addition, the effective heat dissipation area of the heat sink produced by this process is limited. To achieve a better heat dissipation effect, the air volume of the fan must be increased, and increasing the air volume of the fan will produce greater noise.

Heat sink of aluminum street lamp die casting
Processing and forming technology of heat sink
Heat sink bonding process

This type of radiator is first made of aluminum or copper plates into fins, and then combined with a grooved heat sink base using thermal paste or solder. The characteristic of the combined radiator is that the fins break through the original ratio limit, the heat dissipation effect is good, and different materials can be used for the fins. The advantage of this process is that the heat sink Pin-Fin ratio can be as high as 60 or more, the heat dissipation effect is good, and the fins can be made of different materials.

The disadvantage is that there will be an interface impedance problem between the fin and the base that are combined with thermal paste and solder, which affects heat dissipation. In order to improve these shortcomings, two new technologies have been used in the field of radiators.

The first is the gear shaping technology, which uses more than 60 tons of pressure to combine the aluminum sheet with the copper sheet base, and no medium is used between the two. From a microscopic point of view, the two atoms are connected to each other to some extent, thus completely avoiding the drawbacks of the traditional interface thermal resistance caused by the combination of the two, and greatly improving the heat transfer ability of the product.