Compared with ordinary molds, precision molds have higher requirements in the production process. They must strive for excellence in their raw materials, design, processing, accuracy, size, etc. The processing technology must use high-precision processing and molding technology. What are the specific requirements and characteristics of precision molds? Huanke Precision engineers have compiled and collected relevant content for everyone. Six major molding requirements for precision molds.
1. The product specifications are high-precision, with small dimensional tolerances and high-precision specification limits;
2. The product has high repeatability precision standards and must have day, month, and year reliability;
3. The mold shell is made of good material and has sufficient stiffness. The dimensions of the concave mold are precise, smooth and the accuracy between templates is high;
4. Choose high-precision plastic machines to replace basic plastic machines;
5. Use high-precision forming processing technology;
6. Select raw materials that incorporate high-precision molding.
The focus of precision mold processing is definitely on precision. The requirements for dimensional tolerance of precision molds are very high, generally +/-0.005. The main specifications of many precision molds do not allow for slopes, but when producing molds, tolerance levels and small slopes are generally used, such as the mounting studs of transmission gears. When designing drawings for precision molds, you must consider the operability and controllability of processing to ensure the smooth progress of processing.
Four characteristics of precision molds
1. Wear resistance
When the blank material is plastically deformed and transformed in the concave mold of the injection mold, it flows and rolls along the surface of the mold cavity, causing intense friction between the surface of the mold cavity and the blank material, which in turn causes the abrasive tool to become ineffective due to damage. Therefore, the corrosion resistance of the material is one of the most basic and important characteristics of the mold.
Strength is the primary factor affecting wear resistance. Generally speaking, the higher the strength of the mold parts, the smaller 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.
2. Strong ductility
Most of the working conditions of mold shells are very extreme, and some often bear large impact loads, resulting in brittle fracture. In order to avoid sudden brittle fracture of mold parts during operation, high-precision hardware molds must have high hardness and ductility.
The key to the ductility of the mold lies in the carbon content, grain size and structure of the raw material - precision mold manufacturing.
3. Fatigue cracking characteristics
During the working stage of the mold, fatigue and rupture are often caused under the long-term action of cyclic pressure. The types include small kinetic energy repeated impact fatigue rupture, tensile fatigue rupture, contact fatigue rupture and bending fatigue rupture.
The fatigue cracking properties of mold shells mainly depend on their strength, ductility, strength, and the composition of impurities in the raw materials.
4. 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 plastic deformation and rendering it ineffective. Therefore, precision metal mold steel should have high quenching resistance reliability to ensure that the mold shell has high strength and compressive strength at ambient temperature.