Which kind of plastic raw materials are suitable for processing various types of screws in injection molding machines?

The screw of the injection molding machine is a key component in the plastic processing process, and its design characteristics determine its adaptability to different plastic raw materials.Understanding the adaptation relationship between various types of screws and plastic raw materials is essential to optimize the injection molding process and improve product quality.
1. Gradient screw
Structural features
The groove depth of the gradient screw gradually shallows from the feeding section to the metering section.This gradient design allows the plastic to be gradually compressed and plasticized during the conveying process on the screw.
Applicable raw materials
It is more suitable for processing plastic raw materials with good thermal stability and moderate melt viscosity.For example, polyethylene (PE) and polypropylene (PP) are common plastics processed using gradient screws.
Taking PE as an example, it has good thermal stability and can smoothly change from a solid state to a molten state during the conveying and plasticizing process of the gradient screw.The gradual compression characteristics of the gradient screw can fully mix the PE raw materials and ensure the uniformity of the melt, thereby producing plastic products of stable quality.
2. Mutant screw
Structural features
The groove depth of the mutant screw has a sudden change between the feeding section and the metering section.This design can strongly compress the plastic in a short period of time, so that the plastic can be quickly plasticized.
Applicable raw materials
It is suitable for processing plastics with high viscosity and strong heat resistance.Heat-sensitive plastics like polyvinyl chloride (PVC) are more suitable.
PVC is easily decomposed by heat during processing, and the mutant screw can quickly complete the plasticization process, reducing the residence time of PVC in a high temperature environment.Its sudden compression effect can effectively prevent the performance of PVC from degrading due to long-term heating, and help to produce high-quality PVC plastic products.
Three, barrier type screw
Structural features
The barrier screw has a barrier structure in a certain section of the screw. It can separate the plasticized plastic from the plasticized plastic, so that the plasticized plastic can continue to be cut and heated, thereby improving the plasticization quality.
Applicable raw materials
It is very suitable for some filled plastics or plastics that require high-precision plasticization.For example, engineering plastics with fillers such as glass fiber are added.
When processing filled engineering plastics, the barrier screw can ensure that the filler is evenly dispersed in the plastic melt.Because the presence of fillers will increase the viscosity and unevenness of the plastic, the barrier screw can effectively fully mix the filler and the plastic matrix to improve the mechanical properties and appearance quality of the product.
Four, separate screw
Structural features
The separation screw mainly distinguishes the solid bed from the melt through a special structure, so that the solid bed can be compressed and plasticized more effectively, and the temperature fluctuation of the melt can be reduced.
Applicable raw materials
It is suitable for processing plastics that are sensitive to temperature and have large changes in melt viscosity.High-performance plastics such as polycarbonate (PC).
The melt viscosity of PC is very sensitive to temperature, and the separation screw can accurately control its plasticization process to avoid abnormal melt viscosity caused by too high or too low temperature.This kind of screw can fully plasticize the PC at the right temperature and pressure to ensure the transparency and strength of the product.