Comparison of different heat sink production and processing technologies
Basic production process of heat sink:
Product requirements --- Drawing development --- Mold making --- Testing die (extruded aluminum profile) --- Cutting and CNC processing --- Confirmation of functional size samples ) --- Production Input --- Packaging (Inspection) --- Delivery.
2. plug copper heat sink current mainstream of the main material used for the fins is nothing less than two kinds of aluminum and copper. And plug copper process is the combination of aluminum and copper, the respective advantages of the product came into being. The copper plug process is completed by the principle of thermal expansion and contraction. After the aluminum extruded heat sink is heated, the copper core is inserted thereinto, and then the overall cooling is performed. Because no third-party dielectric is used, the copper plugging process can greatly reduce the thermal resistance between the contact surfaces. Not only does it ensure the tightness of the copper-aluminum bond, it also fully utilizes the characteristics of aluminum's fast heat dissipation and copper's fast heat absorption. This copper plugging process has a moderate cost and good heat dissipation effect, and is the mainstream type of heat sink on the market.
3. The compaction method is to stack a large number of copper or aluminum sheets, then press on both sides and polish the section. This section is in contact with the CPU core, and the other side is spread out to serve as a fin for the heat sink. The heat sink made by compaction method is characterized in that the number of fins can be made much. And does not require a high process to ensure that each fin can maintain good contact (or close) with the CPU core. The fins also have close contact by means of compression, and the heat conduction loss between them will be significantly reduced. It is precisely because the heat sink made by compaction method has many fins, the heat dissipation effect of this heat sink is often good, and the weight is much lighter than the traditional heat sink.
5. Bonding type heat sinks Because traditional aluminum extruded type heat sinks cannot break the limit of the thickness and length ratio of fins, they are combined heat sinks. This kind of heat sink is made of aluminum or copper plate first, and then it is combined on a heat sink with grooves by using thermal conductive paste or solder. The characteristics of the combined heat sink are that the fins break through the original proportional limit, and the heat dissipation effect is good, and different materials can be used as the fins. Of course, the shortcomings are also obvious, that is, the use of thermal paste and solder to connect the fin and the base will have an interface impedance problem. This affects heat dissipation. In order to improve these shortcomings, two new technologies have been used in the field of heat sinks. The first is the gear shaping technology. It uses a pressure of more than 60 tons to combine the aluminum sheet in the base of the copper sheet, and no medium is used between aluminum and copper. From a microscopic perspective, the atoms of aluminum and copper are connected to each other to a certain extent, thereby completely avoiding the disadvantages of thermal resistance caused by the traditional copper-aluminum combination and greatly improving the heat transfer ability of the product. The second is the reflow soldering technology. The biggest problem of the traditional bonding heat sink is the interface impedance problem, and the reflow soldering technology is an improvement on this problem. In fact, the process of reflow soldering is almost the same as the traditional bonding type heat sink, except that a special reflow furnace is used, which can accurately set the soldering temperature and time parameters. The solder uses lead-tin alloy to make the welding and the metal to be fully contacted, thereby avoiding missing soldering and empty soldering. Ensure that the connection between the fin and the base is as close as possible, minimize the interface thermal resistance, and control the melting time and temperature of the copper of each solder joint to ensure the uniformity of all solder joints. However, this special reflow furnace is very expensive. Motherboard manufacturers use more, but radiator manufacturers rarely use it.
6. Compared with aluminum extruded fins, the cutting process solves the limitation of the fin thickness-to-length ratio of the fins. The cutting process is to use special tools to cut the entire material into layers of fins. The heat sink fins can be as thin as 0.5mm. In addition, the fins of the heat sink and the base are integrated, so there is no problem of interface impedance. However, the effect of this cutting process in the production process is high waste and low quality rate, which makes the cost high, so the cutting process is mainly biased to copper heat sink.