The viscosity of materials does directly affect their flowability in injection machines, thereby affecting the overall effectiveness of the injection molding process. Viscosity is a physical property that describes the flow resistance of a substance and is crucial for the fluidity of molten plastic during injection molding. Materials with high viscosity have poor flowability during injection, requiring greater injection pressure and higher temperature to ensure smooth injection into the mold; Materials with lower viscosity have better flowability, require lower pressure and temperature for injection, and have faster flow velocity.
When the viscosity is too high, the molten material will encounter greater flow resistance, making it difficult to flow in the injection molding machine, especially when the injection pressure is low, it may not be able to fill the small parts or complex geometric shapes of the mold. This not only affects the quality of the molded parts, but may also lead to excessive load on the injection molding machine, increasing equipment wear and failure rates. To overcome the fluidity problem of high viscosity materials, it is usually necessary to increase the injection temperature and pressure, but this also brings higher energy consumption and more equipment burden.
On the contrary, when the viscosity of the material is low, the flowability of the molten plastic will be better, and the mold can be filled with lower pressure and faster speed during injection, thereby improving production efficiency. However, too low viscosity may cause the material to flow too quickly inside the mold, resulting in overfilling, bubbles, burning, or other molding defects, affecting the quality of the parts.