Factors affecting the size of aluminum profile- Mold changes(二)

Working conditions of the mold

5. Withstand eccentric load and shock load. In extrusion, especially when extruding thick-walled pipes with complex cross-section profiles, hollow profiles, and large diameters and small bores, a large additional stress will be generated in the mold, or a high stress concentration will be caused. In slender parts, thin-walled hollow parts (if the core and hollow extrusion pumping, perforated needle assembly, etc.), the travel stress is very high. Under the action of this stress, the mold is most likely to lose its stability, bending, twisting or breaking.

6. Withstand high friction under high temperature and high pressure. One of the main characteristics of aluminum alloy in extrusion is that it is very easy to "bond" with the surface of the mold, that is, under the action of high temperature and high pressure, the solute atoms such as V, Fe and Si in the alloy penetrate into the surface metal of the mold. Under the action of high temperature and high pressure, these adhered metal layers are constantly formed, and they are constantly destroyed, and after repeated wear, the mold fails.

7. Withstand the action of local stress concentration. Due to the complex shape of the new product, the shape and structure of the corresponding molds and tools (such as flat extrusion cylinders, shafts, tongue molds and planar shunt combination molds, etc.) are also more complex, so it is easy to produce local stress concentration under high temperature and pressure, resulting in local deformation or local collapse.

In short, when extruding, the working conditions of the mold are very harsh, and the factors causing its deformation and damage are also complex. Therefore, in the design should be as far as possible to consider the influence of various adverse factors, choose a reasonable structure.