Advantages, Disadvantages, and Adjustment of Molding Products for Silicone Injection Molding Machines

Silicone product molding is a process used to manufacture silicone items suitable for thermoplastic applications. A tubular parison, produced via extrusion or injection molding, is placed into a mold, and compressed air is blown into the parison, causing it to expand and conform to the mold cavity.

Impact of Silicone Injection Molding Process on Product Precision:

When producing critical injection-molded parts with tight dimensional tolerances, the allowable dimensional variation for each part is minimal—sometimes as low as one or two fluctuations. During production, the primary factor affecting dimensional accuracy is typically the shrinkage rate of the molded part. Higher shrinkage leads to poorer precision. For example, PP and POM parts generally exhibit higher shrinkage rates, resulting in relatively lower dimensional accuracy. Other materials typically have lower shrinkage rates, so under normal injection molding conditions, dimensional accuracy is generally not a major concern.

Adjusting Machine Parameters to Improve Precision:

Machine settings can be adjusted to reduce the shrinkage rate of molded parts, thereby enhancing dimensional accuracy. Significantly increasing injection time and pressure, or extending holding pressure time, can effectively lower shrinkage rates. With reduced shrinkage, dimensional accuracy naturally improves. However, due to the limitations of standard injection molding machines, injection pressure should not be set excessively high to avoid issues like flashing. Therefore, for commonly used general-purpose injection molding machines, the primary method to improve dimensional accuracy is to increase injection time or holding pressure time. To ensure the dimensional accuracy of molded parts, mold precision remains the foundational requirement. Selecting a stable, reliable machine with minimal parameter fluctuations and sufficient pressure capacity is crucial for achieving consistent results.