Screw Selection for Injection Molding Machines
Injection molding machine screws are crucial components that significantly impact product quality and production efficiency. Therefore, adhering to specific principles is essential when selecting the appropriate screw for an injection molding machine.
Choose the Screw Type Based on Plastic Properties:
Different plastics exhibit distinct characteristics, including melting point, viscosity, and flowability. Consequently, it is crucial to select the appropriate screw type based on the specific plastic being used. For instance, for heat-sensitive plastics, employ screws with short or no metering sections to minimize plastic residence time within the screw and prevent decomposition. For easy-filling plastics, utilize screws with deeper metering sections to enhance plasticization quality.
Select Screw Diameter Based on Shot Volume:
Screw diameter plays a pivotal role in determining shot volume. Generally, larger screw diameters correspond to higher shot volumes. However, when selecting screw diameter, it is also essential to consider the injection molding machine's injection pressure and mold clamping force.
Choose Screw Based on Length-to-Diameter Ratio:
The length-to-diameter ratio (L/D) is the ratio of the screw's length to its diameter. It is another critical factor influencing plasticization performance. Generally, a higher L/D ratio results in better plasticization. However, an excessively high L/D ratio can reduce screw rigidity and increase wear.
Select Screw Based on Screw Structure:
Injection molding machine screws come in various structural forms, including tapered screws, abrupt transition screws, and mixed screws.
