1. In order to reduce the deformation of the plastic mold, the heat treatment department should work with the plastic mold design department to improve the design of the plastic mold, such as avoiding the plastic mold structure with a large difference in cross-section size, the shape of the plastic mold, and the symmetry and complexity of the plastic mold. Structure, etc.
2. When the shape of the plastic mold cannot be changed, in order to reduce the deformation, some other measures can be taken. The overall consideration of these measures is to improve the cooling conditions so that the parts are evenly cooled; in addition, various coercive measures can be assisted to limit the quenching deformation of the parts.
3. For the deformation of the asymmetric plastic mold, it is also the result of the combined effects of thermal stress and tissue stress. For example, for a thin-walled thin-walled mold, since the mold wall is thin, the internal and external temperature difference during quenching is small, and thus the thermal stress is small; but it is easy to be hardened and the tissue stress is large, so the deformation tends to expand the cavity.
4. For symmetrical plastic molds, the deformation tendency can be considered according to the cavity size, outer dimensions and height.
When the wall of the plastic mold is thin and the height is small, it is easier to be hardened, and the tissue stress may play a major role. Therefore, the cavity tends to expand. On the other hand, if the wall thickness and height are large, it is not easy to be hardened. At this time, thermal stress may play a major role, and therefore, the cavity tends to shrink.
In the production practice, it is necessary to consider the specific shape of the part, the steel type used and the heat treatment process, etc., and continuously summarize the experience through practice. Due to the actual production, the outer dimensions of the plastic mold are often not the main working size, and can be corrected by grinding after deformation.