| 塑料模具的工作条件 |
| 添加时间：2019/8/7 14:09:24 浏览次数： |
| 塑料模具的工作条件与冷冲模不同，一般须在150°C-200°C下进行工作，除了受到一定压力作用外，还要承受温度影响。现根据塑料成型模具使用条件、加工方法的不同将塑料模具用钢的基本性能要求大致归纳如下: The working condition of plastic die is different from that of cold punching die. Generally, it must work under 150 C - 200 C. Besides being subjected to certain pressure, it must also bear the influence of temperature. The basic performance requirements of steel for plastic moulds are summarized as follows according to the different working conditions and processing methods of plastic moulds. 1、足够的表面硬度和耐磨性 1. Adequate surface hardness and wear resistance 塑料模的硬度通常在50-60HRC以下，经过热处理的模具应有足够的表面硬度，以保证模具有足够的刚度。模具在工作中由于塑料的填充和流动要承受较大的压应力和摩擦力，要求模具保持形状的精度和尺寸精度的稳定性，保证模具有足够的使用寿命。模具的耐磨性取决于钢材的化学成分和热处理硬度，因此提高模具的硬度有利于提高其耐磨性。 The hardness of plastic moulds is usually below 50-60 HRC. The heat treated moulds should have sufficient surface hardness to ensure that the moulds have sufficient stiffness. Because the filling and flowing of plastics must bear large compressive stress and frictional force in the work of the die, it is required to keep the shape accuracy and dimensional accuracy of the die stable, and ensure that the die has sufficient service life. The wear resistance of the die depends on the chemical composition of the steel and the hardness of heat treatment, so improving the hardness of the die is beneficial to improving its wear resistance. 2、优良的切削加工性 2. Excellent machinability 大多数塑料成型模具，除EMD加工外还需进行一定的切削加工和钳工修配。为延长切削刀具的使用寿命，提高切削性能，减少表面粗糙度，塑料模具用钢的硬度必须适当。 In most plastic moulds, besides EMD processing, certain cutting and fitter repairs are needed. In order to prolong the service life of cutting tools, improve cutting performance and reduce surface roughness, the hardness of steel for plastic die must be appropriate. 3、良好的抛光性能 3. Good polishing performance 高品质的塑料制品，要求型腔表面的粗糙度值小。例如，注塑模型腔表面粗糙度值要求小于Ra0.1~0.25的水平，光学面则要求Ra<0.01nm，型腔须进行抛光，减小表面粗糙度值。为此选用的钢材要求材料杂质少、组织微细均一、无纤维方向性、抛光时不应出现麻点或桔皮状缺陷。 For high quality plastic products, the surface roughness of the cavity is required to be small. For example, the surface roughness of injection mold cavity is required to be less than Ra 0.1-0.25 level, while the optical surface is required to be Ra < 0.01 nm. The cavity must be polished to reduce the surface roughness. For this reason, the selected steel requires less impurities, uniform microstructure, no fiber orientation, and no pitting or orange peel defects in polishing. 4、良好的热稳定性 4. Good thermal stability 塑料注射模的零件形状往往比较复杂，淬火后难以加工，因此应尽量选用具有良好的热稳定性的，当模具成型加工经热处理后因线膨胀系数小，热处理变形小，温度差异引起的尺寸变化率小，金相组织和模具尺寸稳定，可减少或不再进行加工，即可保证模具尺寸精度和表面粗糙度要求。 Plastic injection mold parts are often complex in shape and difficult to process after quenching. Therefore, good thermal stability should be selected as far as possible. When the mold is processed by heat treatment, the linear expansion coefficient is small, the heat treatment deformation is small, the size change rate caused by temperature difference is small, the metallographic structure and the size of the mold are stable and can be reduced. The dimensional accuracy and surface roughness of the die can be guaranteed without further processing. |
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