How to choose the mold material reasonably in the injection mold opening

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-resistant mold steel (such as YG15 YG20); for small batches or new product trial production, zinc alloy, bismuth-tin alloy and other molds can be used Material: For general molds that are easy to deform and break and fail, high-strength and high-toughness materials (T10A) should be selected; hot forging molds should be selected with good toughness, strength, wear resistance and thermal fatigue resistance. (such as 5CrMnMo); the die-casting mold should be made of alloy steel with high thermal fatigue resistance and high temperature strength (such as 3Cr2W8V); the plastic mold should be made of materials that are easy to cut, dense in structure and good polishing performance. In addition, when designing the punch and die, it is advisable to select dies with 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), die The service life can be increased by 5~6 times.

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② Reasonable mold structure. The principle of mold design is to ensure sufficient strength, rigidity, concentricity, neutrality and reasonable blanking gap, and reduce stress concentration to ensure that the parts produced by the mold meet the design requirements, so the main working parts of the mold (such as The convex and concave dies of the punching die, the movable and fixed dies of the injection mold, the upper and lower dies of the die forging die, etc., require high guiding precision, good concentricity and reasonable blanking clearance.

When designing the mold, the following aspects should be considered.

a. Support and centering protection, especially when designing small hole punches, the self-guided structure can be used to prolong the life of the mold.

b. For weak parts such as included angles and narrow grooves, in order to reduce stress concentration, it is necessary to use arc transitions, and the arc radius can be 3~5mm
③ For the die with complex structure, the mosaic structure can also be used to reduce stress concentration. ④ Reasonably increase the clearance, improve the stress state of the working part of the punch, so that the punching force, the force of unloading and the force of pushing the piece are reduced, and the wear of the cutting edge of the punch and the punch is reduced.