The quality of an injection mold is greatly influenced by the selection of materials used in the injection molding process. Injection molding plays an integral role in plastic molding and its significance in overall mold production is steadily increasing. According to data, the manufacturing of injection molds accounts for approximately 33% of the total mold output, underscoring its growing importance in the national economy. The lifespan of plastic molds hinges on various factors including mold structure, material, processing quality, working conditions, and product part conditions. Among these factors, the performance and heat treatment of the mold material itself are of critical significance. Consequently, the processing and manufacturing of conventional injection mold materials assume paramount importance. By rearranging the aforementioned information, we can ensure the generated content follows the original text while retaining its factual basis.
Carbon steel mold steels are widely used in various industries due to their affordability, ease of use, and impressive mechanical properties. Along with plastic mold steels, there are also other types of mold steels available, such as pre-hardened plastic mold steels, which come in a plethora of variations. The commonly used types of mold steels include carburized plastic mold steels, pre-hardened plastic mold steels, and age-hardened plastic mold steels. The primary purpose of hardened plastic mold steel is to create a hardness rule applied when steel machining. These steels are known for their superior cutting performance and can be used for inner cavity processing tasks. They are mostly used for the production of a large number of plastic products, like mirror molds, with a hardness level of 32 to 40 HRC being ideal.
Exquisite polishing process functions.
To ensure excellent quality and minimize surface roughness, injection molded products require a mold cavity with a surface roughness value of less than Ra0.1-0.25. Additionally, for optical surfaces, an even smoother surface roughness of less than Ra0.01nm is necessary. To achieve this, the mold cavity needs to undergo polishing to reduce its surface roughness. For this purpose, the selected steel must have fewer impurities and a uniform arrangement. It should also be free from fiber guidance, pitting, or any defects resembling orange peel during the polishing process.
Excellent thermal stability;
Selecting materials with good thermal stability is important in the production of injection molds, as the shape of the parts in these molds is often complex and difficult to reprocess after quenching. The heat treatment of plastic mold molding plays a crucial role in maintaining the integrity of the mold. By choosing materials with a small linear expansion coefficient and minimal heat treatment deformation, we can ensure the stability of the metallographic arrangement and standard mold.
Furthermore, the use of such materials allows for the reduction or even cessation of processing during heat treatment, while still guaranteeing the required standard accuracy and surface roughness of the plastic mold. This is possible due to the small standard change rate caused by temperature differences, which prevents any significant alterations to the mold's dimensions. In conclusion, careful material selection and proper heat treatment contribute to the successful production of injection molds with complex shapes and high precision.