Material Selection Requirements for Plastic Molds

Plastic molds are important tools for producing plastic products. Their quality will directly affect the quality of plastic products, so we must pay attention to plastic molds. In the actual production process, plastic molds are used very frequently, so their material selection is also very important. So, what are the material selection standards for plastic molds?

1. Sufficient surface hardness and wear resistance

The hardness of plastic molds is usually below 50-60HRC. Heat-treated molds should have sufficient surface hardness to ensure that the molds have sufficient rigidity. During work, the molds must withstand greater compressive stress and friction due to the filling and flow of plastics. The molds are required to maintain the accuracy of the shape and the stability of the dimensional accuracy to ensure that the molds have sufficient service life. The wear resistance of the mold depends on the chemical composition and heat treatment hardness of the steel. Therefore, increasing the hardness of the mold is conducive to improving its wear resistance.

2. Excellent cutting processability

Most plastic molds, in addition to EMD processing, also require some cutting processing and bench repair. In order to extend the service life of the cutting tool, improve cutting performance, and reduce surface roughness, the hardness of the steel used for plastic molds must be appropriate.

3. Good polishing performance

High-quality plastic products require a small roughness value on the cavity surface. For example, the surface roughness value of the injection mold cavity is required to be less than Ra0.1~0.25, and the optical surface requires Ra<0.01nm. The cavity must be polished to reduce the surface roughness value. For this purpose, the steel selected requires less material impurities, fine and uniform structure, no fiber directionality, and no pitting or orange peel defects during polishing.

4. Good thermal stability

The shape of the parts of the plastic injection mold is often more complex and difficult to process after quenching. Therefore, it is necessary to try to use those with good thermal stability. After the mold molding process is heat treated, the linear expansion coefficient is small, the heat treatment deformation is small, the dimensional change rate caused by the temperature difference is small, the metallographic structure and the mold size are stable, and the processing can be reduced or no longer performed, which can ensure the mold size accuracy and surface roughness requirements.

Qingdao Xueyu Molding Products Co., Ltd. is mainly engaged in the design and manufacturing of injection molds, injection molding and secondary processing (spraying, pad printing, ultrasonic welding, stamping), etc. For more information about plastic mold, please contact us.

Website: www.xyzmould.com

Address: No.18 Henan Head Road, Henan Head Community, Jihongtan Street, Qingdao Industrial Park, Shandong Province, China

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