Compared with ordinary moulds, precision molds have higher requirements in the production process, and they must strive for excellence in their raw materials, design, processing, precision, size, etc., and the processing technology must use precision injection molding technology. What are the specific requirements and characteristics of precision molds? Next, we will sort out and collect relevant content for you.
The specifications of the product are high-precision, the dimensional tolerance is small, and there are high-precision specification boundaries;
The repeated precision standard of the product is high, and the size reliability of the day, month, and year is required;
The material of the mold is good, the rigidity is sufficient, the precision and smoothness of the shape and size of the die and the accuracy between the templates are high;
Use high-precision plastic machines to replace basic plastic machines;
Select high-precision forming process;
Select raw materials that are integrated into high-precision forming.
The focus of precision mold processing must be on precision. Precision molds have very high requirements for dimensional tolerances, generally +/-0, 005. The main specifications of many precision molds do not allow slopes, but in mold production, tolerance grades and small slopes are generally used flexibly, such as transmission gear installation column heads, etc. Precision molds must consider the operability and controllability of processing when designing drawings to ensure the smooth progress of processing.
When the blank is plastically deformed and transformed in the concave mold of the injection mold, it flows and rolls along the surface of the cavity, causing intense friction between the surface of the cavity and the blank, which in turn causes the mold to be invalid due to damage. Therefore, the corrosion resistance of the material is one of the most basic and important characteristics of the mold.
Intensity is the primary factor affecting wear resistance. In general, the higher the strength of the mold parts, the lower the wear rate and the higher the wear resistance. In addition, the wear resistance is also related to the type, total number, shape, size and distribution of cementite in the material.
Most of the working conditions of the mold are very extreme, and some often bear a large impact load, which leads to brittle fracture. In order to avoid sudden brittle fracture of mold parts during work, high-precision metal molds must have high hardness and ductility. The key to the ductility of the mold is the carbon content, grain size and structure of the raw material.
Fatigue cracking characteristics
In the working process of precision molds, under the long-term action of cyclic pressure, fatigue fractures are usually caused. Its types include small kinetic energy repeated impact fatigue fracture, tensile fatigue fracture, contact fatigue fracture and bending fatigue fracture. The key to the fatigue cracking characteristics of the mold lies in its compressive strength, ductility, strength and the composition of the dopant in the raw material.
High temperature characteristics
When the operating temperature of the mold is high, the strength and hardness will be reduced, causing initial damage to the mold or causing plastic deformation to be invalid. Therefore, the metal precision mold steel should have high quenching resistance reliability to ensure that the mold has high strength and compressive strength at ambient temperature.