Does the injection pressure and speed of liquid silicone affect the molding of liquid silicone?
Liquid silicone, as a high-performance elastic material, has a wide range of applications in medical, electronic, automotive and other fields. During the molding process, injection pressure and speed are two crucial process parameters.
The injection pressure directly determines the fluidity and filling ability of liquid silicone in the mold. When the injection pressure is too low, liquid silicone cannot fully fill every corner of the mold, resulting in defects such as material shortage and bubbles in the product. Excessive injection pressure may lead to excessive compression of silicone in the mold, resulting in product deformation, dimensional instability, and other issues. Therefore, a reasonable injection pressure selection is the key to ensuring the quality of liquid silicone molding.
So, how to determine the appropriate injection pressure? This needs to be comprehensively considered based on the viscosity of liquid silicone, the structure and size of the mold, and the performance of the injection machine. Liquid silicone with higher viscosity requires higher injection pressure to ensure its fluidity; The complex mold structure requires higher injection pressure to ensure that silicone can fully fill every corner of the mold. Meanwhile, the performance of the injection machine is also an important factor determining the injection pressure, and different models of injection machines have different pressure and flow control capabilities.
In addition to injection pressure, injection speed is also another important factor affecting the formation of liquid silicone. Excessive injection speed may cause uneven flow of silicone in the mold, resulting in defects such as unevenness and sintering lines on the product surface. However, excessively slow injection speed may lead to premature solidification of silicone in the mold, affecting the integrity and performance of the product.
The reasonable injection speed selection should be determined based on the solidification speed of liquid silicone, the temperature of the mold, and the design requirements of the product. Generally speaking, faster injection rates are suitable for liquid silicone with faster curing rates and molds with higher temperatures; The slower injection speed is suitable for liquid silicone with slower curing speed and molds with lower temperatures.
In the actual production process, the injection pressure and speed of liquid silicone often need to be finely adjusted according to specific process requirements and product characteristics. This requires a deep understanding of the physical properties of liquid silicone, the structure of the mold, and the performance of the injection machine. At the same time, it is necessary to accumulate and adjust process parameters through a large amount of experiments and practical experience to achieve the best molding effect.
The process of liquid silicone injection molding can be roughly divided into stages such as mold closing, injection molding, pressure holding, cooling, mold opening, and product removal. During these stages, temperature, pressure, and time are key factors that affect the quality of the molding process. Temperature control can be improved through stages such as barrel temperature, nozzle temperature, and mold temperature.