Research on the influence of precision and stability of plastic molding equipment on the dimensional stability of finished products

The precision and stability of plastic molding accessories, such as molds and injection molding machines, are key factors in determining the dimensional stability of finished products. This article will explore in depth how mold precision and injection molding machine parameters affect the dimensional stability of plastic products, and propose corresponding optimization strategies.

Mold precision: the cornerstone of shaping precise dimensions
As the core component in the plastic molding process, the precision of the mold directly determines the dimensional accuracy of the final product. The cavity size, tolerance control and overall manufacturing accuracy of the mold are the primary considerations. High-precision molds can ensure that the plastic melt is evenly filled during each injection process and reduce the dimensional deviation caused by mold manufacturing errors. Once the mold is worn or has manufacturing defects, such as uneven cavity surface and dimensional deviation beyond the design range, these will be directly reflected in the finished product, resulting in inconsistent dimensions and even affecting the assembly and function of the product.

In addition, the thermal expansion coefficient and temperature control of the mold are also factors that cannot be ignored. During the plastic injection molding process, the mold needs to withstand the heat of the high-temperature plastic melt, resulting in thermal expansion. If the material of the mold is improperly selected or the temperature control system is unstable, it will cause changes in the mold size, which will affect the dimensional accuracy of the finished product. Therefore, the use of mold materials with low thermal expansion coefficients and precise temperature control strategies are crucial to maintaining mold dimensional stability.

Injection molding machine parameters: precise control of the molding process
As the main equipment for plastic molding, the setting of various parameters of the injection molding machine directly affects the filling, holding and cooling process of the plastic melt, and thus affects the dimensional stability of the finished product. The injection pressure determines whether the melt can fully fill the mold cavity. Insufficient pressure will lead to dissatisfaction, while excessive pressure may cause overflow or mold damage. The injection speed affects the fluidity and filling efficiency of the melt. Too fast or too slow may cause dimensional deviation.

The length of the holding time is directly related to the degree of compaction of the melt in the mold, which in turn affects the density and dimensional stability of the finished product. The cooling time is the key link to ensure that the melt is fully solidified and avoid shrinkage and deformation. If the cooling is uneven or the time is too short, the finished product may shrink unevenly after demolding, resulting in dimensional changes.

Optimization strategy: improve precision and stability
The following optimization strategies can be adopted to address the impact of mold precision and injection molding machine parameters on the dimensional stability of finished products:

Mold upgrade and maintenance: Use high-precision processing technology and high-quality materials to manufacture molds, regularly inspect and maintain molds, repair wear and defects in a timely manner, and ensure that the molds maintain high precision for a long time.

Temperature control system optimization: Install high-precision temperature sensors and controllers to achieve precise control of mold temperature and reduce dimensional changes caused by thermal expansion.

Fine adjustment of injection molding machine parameters: Use advanced injection molding machine control systems to accurately set injection pressure, speed, holding time and cooling time according to material properties and product requirements to achieve precise control of the molding process.

Process monitoring and quality feedback: Implement online monitoring and quality control systems to collect and analyze production data in real time, detect and correct deviations in a timely manner, and ensure the consistency and stability of finished product dimensions.