1. In the process of aluminum alloy extrusion forming, two steps are needed: cooling and stretching. During the cooling process, especially for larger aluminum radiator profiles, thermal expansion and cold contraction will be more obvious. Measurements are difficult to be very accurate, as differences in shape, material, or cooling conditions can affect the final size. Many mold designers rely on years of experience to control the reduction deviation.
2. Due to the high temperature and low hardness of aluminum in the extrusion process, it is easy to bend and deformation during the handling process, so it should be straightened. In the straightening process, the bonding mode of aluminum inner crystals will change, so that the strength of aluminum is improved. Before and after straightening, the external size of aluminum will be reduced by 3-4 pieces. Therefore, straightening will also affect the dimensional accuracy of the final aluminum radiator profiles to a certain extent.
3. In the extrusion process, the machining technology level of the die, such as flatness, die burr or design defects of the deflector, will affect the dimensional accuracy.
Aluminum radiator profiles mold design considerations
1. Because of the different size of the mold section, the flow rate and velocity of aluminum through various sections of the mold are different. When aluminum is subjected to the same pressure, most of the flow area of aluminum is large, but the radiator with small cross-sectional area passes through less aluminum, which is easy to occur material shortage. Also, the area with a large cross-sectional area, the flow rate is faster than the area with a small cross-sectional area. Therefore, in the design, must consider how to solve the problem of different flow and velocity.
2. The flow rate of aluminum can be controlled according to the dynamic balance principle of friction when extrusion die. Aluminum creates friction with the inner surface of the die during extrusion. Die in EDM processing, will be processed in the die a step, different parts of the step depth is different. At the final bottom where the gap is smaller, the depth will be shallower. At the bottom of the sink, the steps go deeper. The function of the step is to control the total friction force during aluminum extrusion, through which the discharge speed is controlled. This design can also play the role of air avoidance, when the material will not hang injury.