The quality of the materials used will directly affect the performance of the mold development and use, so we need to pay attention to the main points when selecting mold materials, so as to avoid the mold does not meet the requirements and cannot be used normally, or the quality of the developed workpiece will be problematic. In order to let everyone better use the mold, the following tells you the points that you should pay attention to when choosing mold materials.
1. Selection of mold materials
When selecting mold materials, it should be selected according to different production batches, process methods and processing objects. In mass production, long-life mold materials should be selected, such as cemented carbide, high-strength, high-wear mold steel (such as YG15, YG20); for small batches or new product trial production, zinc alloy, bismuth tin alloy, etc. Mold material; for general-purpose molds that are easy to deform and break and fail, high-strength, high-toughness materials (T10A) need to be selected; hot forging molds must be selected with good toughness, strength, mold resistance, and thermal fatigue resistance. Materials (such as 5CrM-nMo); die-casting molds should be made of alloy steel with high thermal fatigue resistance and high-temperature strength (such as 3Cr2W8V); plastic molds should be made of materials with easy cutting, dense structure and good polishing performance. In addition, when designing punch and die, it is advisable to choose molds of different hardness or different materials to match, such as: tool steel for punch (such as T10A), high carbon and high chromium steel for die (such as Cr12, Cr12MoV), The service life of the mold can be increased by 5 to 6 times.
2. Reasonable mold structure
The principle of mold design is to ensure sufficient strength, rigidity, concentricity, neutrality and reasonable blanking clearance, and reduce stress concentration to ensure that the parts produced by the mold meet the design requirements. Therefore, the main work components of the mold (such as the convex and concave molds of the punching die, the movable and fixed molds of the injection mold, the upper and lower molds of the forging mold, etc.) require high guiding accuracy, good concentricity and neutrality, and punching The clearance is reasonable.
When designing a mold, what should be considered is:
① Pay attention to guiding support and centering protection when designing the punch. Especially when designing the small hole punch, the self-guided structure can be used to extend the life of the mold.
②For weak parts such as included angles and narrow grooves, in order to reduce stress concentration, circular arc transitions are required, and the arc radius R can be 3~5mm.
③The use of inlay structure for the concave mold with complex structure can also reduce stress concentration.