Due to their light weight, aesthetic appearance, and ease of being processed into good thermal conductivity and complex shapes, magnesium-aluminum alloys are widely used in heat dissipation devices. Magnesium-aluminum alloy heat dissipation devices mainly come in three types: flat and wide shape, comb shape or fishbone shape; or elliptical outer heat dissipation fins in a radial or branch-like pattern. Their aspect ratio is large; the wall thickness difference is large. Generally, the heat dissipation fins are thin, while the thickness of the base plate at the root is large. Therefore, the design, manufacture and production of molds for heat dissipation profiles bring great difficulties. Their common feature is that the distance between the heat dissipation fins is short, and a slot-like shape is formed between two adjacent heat dissipation fins. The production of magnesium-aluminum alloy heat dissipation profile profiles must start from the quality of the ingot, the material and design of the mold, reducing the extrusion pressure, and the extrusion process. Then, let's take a look at the extrusion technology of heat dissipation profile profiles together! 
1. Quality requirements for the ingots 
The alloy composition of the ingot must strictly control the impurity content. The contents of Mg and Si are generally controlled at the lower limit of the national standard. The Mg content is 0.45% to 0.55%, and the Si content is 0.25% to 0.35%. The ingot must undergo sufficient homogenization treatment to ensure the cleanliness of the alloy melt. For 6063 alloy, the contents of Fe, Mg, and Si must be controlled. The content of Fe must be less than 0.2% to ensure uniformity and consistency of the structure and properties of the ingot. 
The surface of the ingot should be smooth and should not have inclusions or sand particles. The end face of the ingot should be flat and should not be cut in a stepped shape or have a too large slope. The slope should be within 3 degrees. When the ingot directly contacts the mold, if the end face of the ingot is not flat, it will first come into contact with the mold, causing stress concentration. Due to the stepped shape or excessive cutting angle, when using a flat mold to extrude a heat dissipation profile, if no guide beam is designed, the teeth of the mold are prone to deformation, and the material is prone to clogging or blockage. 
2. Requirements for the mold 
The molds for radiator profiles are mostly slender teeth, so they must withstand a large compressive force. Each tooth requires high strength and toughness. If there are significant differences in their properties, the teeth with poorer strength and toughness are prone to breakage. Therefore, the heat treatment of the molds is very important. It should undergo vacuum heating and quenching, and be quenched with high-pressure pure nitrogen. This can ensure uniform performance of each part of the mold after quenching. After quenching, with the premise that the hardness of the mold is HRC 48-52, the quality of the mold steel must be reliable. Use H13 steel produced by reliable quality manufacturers, or choose high-quality imported steel. Perform three re-heating processes to give it sufficient toughness. This is an important condition to prevent the mold from breaking at the teeth. 
To design a relatively mature section, embedding alloy steel molds is also a good method. The alloy steel molds, due to their excellent rigidity and wear resistance, are less likely to deform, which is conducive to the shaping of the radiator profiles. 
3. Reduce pressure 
To prevent mold breakage, it is related to factors such as the length of the ingot, the size of the alloy's deformation resistance, the state of the ingot, and the degree of deformation. Therefore, the casting rod for extruding aluminum profiles cannot be too long. It should be approximately 0.6 to 0.85 times the length of a common casting rod. In particular, a casting rod that is 0.6 to 0.85 times the length of the usual casting rod is used for trial production. For the cross-section of complex heat dissipation profiles, in addition to shortening the length of the casting rod, it is also possible to consider using short casting of pure aluminum for trial extrusion. During the trial production and extrusion of a casting rod, in order to be able to smoothly produce qualified products, it is preferred to use shorter casting rods. After the trial extrusion is successful, normal casting of the ingot is used for production. 
The homogenization annealing of ingots not only ensures uniformity of the structure and properties, but also improves the extrusion performance and reduces the extrusion pressure due to the generally larger cross-sectional area of the extrusion profiles and the extrusion coefficient usually being within 40. Therefore, the ingots need to undergo homogenization annealing. Regarding the influence of the deformation degree, its impact is relatively small. 
4. Compression Technology 
The key to the production of radiator profiles lies in the trial molding of the extrusion die. If possible, computer simulation can be used first to check whether the working sections of the die design are reasonable, and then the die can be tested using the extrusion machine. One trial run is very important. When the operator advances the main piston and pushes it upwards, it should move slowly at a pressure of less than 8 MPa. Some people simply look at the mold outlet and evenly squeeze out the heat sinks of the mold from the mold hole by pressing the mold. After the trial production is successful, if further stamping is required, the stamping speed must be controlled to ensure smooth operation. When producing radiator profiles, please pay attention to the heating temperature of the mold to avoid the mold temperature being close to the casting billet temperature. When the temperature difference is too large, the pressing speed during the upward push is slow, so the metal temperature drops, which can easily cause blockage and uneven flow rate. 
The above description pertains to the extrusion technology of radiator profiles. If you want to know more, please feel free to contact us at any time!