What are the requirements for the production performance of plastic mold opening
by：Vowin Rapid Prototyping2023-02-09
The design and development of plastic molds are generally integrated with product production. After the mold is formed, it can be mass-produced on a large scale. But before the mass production, it must be ensured that there is no problem with the mold. The working conditions of the plastic mold are different from those of the cold mold. Generally, it needs to work at 150°C-200°C. In addition to a certain pressure, it is also affected by the temperature. Therefore, there are certain special requirements for the mold. So what are the basic performance requirements of plastic molds? Wo Neng Precision will take you to understand. 1. Sufficient surface hardness and wear resistance The hardness of the plastic mold is generally below 50-60HRC. The mold after heat treatment must have sufficient surface hardness to fully ensure the rigidity of the mold. During the work, the mold needs to bear greater pressure stress and friction due to the charging and flow of plastic, so the mold must maintain the accuracy of shape and the stability of dimensional accuracy in order to ensure the full service life of the mold. The wear resistance of the mold depends on the chemical composition and heat treatment hardness of the steel, so increasing the hardness of the mold helps to improve the wear resistance. 2. Good processability
Most plastic molding tools require specific cutting and fixture maintenance in addition to EMD processing. In order to prolong the life of cutting tools, improve cutting performance, and reduce surface roughness, the hardness of steel for plastic molds must be appropriate.
3. Good polishing performance High-quality plastic products with small hollow surface roughness value. For example, the pocket surface roughness value of the injection molding model needs to be less than the level of Ra 0.1 ~ 0.25, and the optical surface requires Ra<0.01nm, the cavity must be polished to reduce the surface roughness value. The steel selected for this purpose requires less material impurities, fine and uniform structure, no fiber directionality, and no pitting or orange peel-like defects during polishing. 4. Good thermal stability The shape of plastic injection mold parts is often very complicated, and it is difficult to process after quenching, so it is necessary to choose good thermal stability. After mold forming heat treatment, the linear expansion coefficient is small, the heat treatment deformation is small, and the dimensional change rate caused by temperature difference is small. The metal structure and the dimensional stability of the mold are reduced or no longer processed, which can ensure the dimensional accuracy and surface roughness requirements of the mold. 5. Grade 50 carbon steel has certain strength and wear resistance, and it is often used as formwork material after adjustment. High carbon tool steel and low alloy tool steel have high strength and wear resistance after heat treatment, and are often used for forming parts. However, high carbon tool steel is only suitable for forming parts with small size and simple shape due to heat treatment deformation. With the development of the plastics industry, the complexity and precision of plastic products are getting higher and higher, and the requirements for mold materials are also getting higher and higher. Complex and highly corrosive plastic molds use PMS, corrosion-resistant steel (such as PCR), and low-carbon maraging steel (such as 18Ni-250), which have good cutting, heat treatment and polishing performance, and high strength. The above will be some key points of plastic mold production and injection molding. Friends who want to consult more about mold development, manufacturing, design and other related details can contact us. And other business, please call to discuss cooperation.