[China Aluminum Network] The quality and production efficiency of aluminum profiles are closely related to the design and structure of the extrusion die. Based on the work experience of the past few years, the author briefly introduces several aluminum profile extrusion die that often occur in practical production. Optimized design, discuss with your peers.
1 Optimization of Large Section Hollow Profile Moulds
In the case of conventional design, the hollow section with large hollow section has often appeared large surface waves, poor plane clearance, obvious weld defects, etc. These problems are usually caused by the irrationality of the mold design structure. To this end, the author in the mold design: the upper mold uses a partial bridge, the lower mold in the silo plus ribs design. Schematic design of the mold shown in Figure 1.
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Because in the production process, defects such as large surface wave and out-of-plane clearance of the profile are generally caused by the fact that the large surface diverging hole is close to the center and the metal flow velocity is fast. Therefore, an appropriate length is set in the large surface die hole in the welding chamber. The ribs, so that when the metal flows to the die hole, the ribs act like a low wall to hinder the flow of metal, if the barrier is too much, it is easy to repair the mold. At the same time, the quality of certain welds has also been optimized accordingly.
For some rectangular cavities, square pipe profiles with relatively large aspect ratios, the weld line often appears on the large-surface decorative surface. The symmetric bridge can now be changed to a partial bridge type. The schematic diagram of the design is shown in Figure 2.
The weld is formed because the metal flow is not fully welded before passing through the split hole into the hole under the bypass bridge. It is of course ideal for us to obtain high-strength and high-quality welds. However, if in the production process, the weld seam inevitably appears on the large or decorative surface of the profile, it may be as far away as possible from the large surface or the decorative surface. In the case of a split hole as in (Figure 2), the midline of the mold bridge is shifted outwards (a:b=2:1, a1=a2).
In general, since the flow rate of the metal in the large-surface diverging hole is fast, when the form of the diversion bridge is designed to be a partial bridge type, the space filled in both sides of the material flow in the large-surface diverging hole is increased, and the center of the diversion bridge is added. With the outward shift of the line, the position of the flow soldering station also shifts outward. Therefore, the flow rate of the large-surface metal is adjusted in this way, and the weld seam is further away from the center surface.
2 Optimization of Double-mode Hole Easy-wall Partial Hollow Profile Mould
Under normal circumstances, regardless of whether the two holes are ejected up or down or left and right, the metal flow near the center side will be fast, and the feeding will be sufficient to cause the upper mold core to elastically deform outwards to cause the profile to be far away from the center. Partial wall defects. Therefore, in the process of mold design, when the profile section size is heavy, the section size that normally generates the offset wall is left with an offset margin in advance. If the two die holes share the center diverting hole, in order to ensure relative stability of the feeding of the two die holes, a partition type diverting tendon may be added in the middle position of the two holes in the bin, which is also favorable for repairing the die.
3 Optimization of flat profile molds with small openings and large wall area
In the case of a planar mold design in which the material is usually fully straightened, the cantilever elastic deformation is likely to be so large that breakage, falling, and the like occur. In this case, it can be designed as a hanging mandrel, but repairing the mold is not easy. Some profile openings are very small and almost closed. This can be combined mode, but the opening needs to be tightly fitted.
In general, the flat profile with small opening and large arm area can design the straight feed plate as a bridge feed plate or a cantilever bridge feed plate, and the forced wall surface under the bridge can be applied to the profile. Cantilever protection, when the metal stream fills the mold hole, the metal flow from the feed plate through the bridge feed plate bridge does not directly affect the cantilever shield, which reduces the positive pressure on the cantilever of the mold, thus Improve the cantilever's stress state. Extended mold life.
4 Optimum Design of Long Profile Plane Profile Mould with Long Ratio of Length to Thickness
Due to the relatively large thickness-to-thickness ratio of the profile, the wall thickness is sometimes relatively thin, and the metal flow velocity near the center is relatively fast. It is only limited by the length of the working belt to adjust the material flow velocity in the die hole. Therefore, deformation defects are easily generated. The bridge type feeding rice shown in Fig. 4-2 is adopted, which can effectively adjust the intermediate metal flow rate, so that the velocity of the material flow in the die holes can be balanced and good results can be obtained.
5 Conclusion
Practice has proved that the above-mentioned optimization of aluminum extrusion die design is effective in actual production. Extrusion of aluminum alloy profiles compared to the past, forming, dimensional accuracy, easy to guarantee, the surface quality has also been a good improvement. Thus, the production efficiency of the profile extrusion is greatly improved and the production cost of the product is reduced.
For the extrusion die design of aluminum extrusion products, along with the rapid development of various industries in the society, the shape of the profile of the profile is complicated and diversified, and it is designed according to the common and common forms, and there are many deficiencies. Therefore, in order to obtain high-quality profiles, we must constantly learn and accumulate in production and life, and constantly reform and innovate.
