What factors affect the extrusion effect of PVC Gutter Extruder

1. Raw material characteristics
PVC resin quality: PVC resins with different degrees of polymerization have very different melt viscosities. PVC resins with high degrees of polymerization have high melt viscosity and poor fluidity, and require higher pressure and temperature to ensure good molding effects during extrusion. For example, PVC resins with a degree of polymerization of 1000 are more difficult to operate during extrusion than resins with a degree of polymerization of 800. If the extrusion parameters are not adjusted, it may cause uneven extrusion and ripples on the surface of the profile.
The particle size and distribution of PVC resin are also important. Uneven particles will affect the conveying and plasticization of raw materials in the screw. If the particle size difference is too large, small particles may flow in the gaps between large particles, resulting in uneven plasticization, and the extruded rain gutters may have inconsistent local hardness.
Additive ingredients: The type and amount of stabilizer affect the thermal stability of PVC. During the extrusion process, PVC will be subjected to high temperatures. If the stabilizer is insufficient, PVC is easy to decompose at high temperatures, causing the profile to discolor and become brittle. For example, lead salt stabilizers can effectively prevent PVC from decomposing, but if the amount is lower than the recommended value, the performance of PVC will be significantly reduced when the extrusion temperature is high.
Lubricants are added to reduce the friction between the melt and the screw, barrel and mold. Too much lubricant will cause the melt to "slip" in the mold, making the size of the extruded profile unstable; while insufficient lubricant will increase friction, which may cause local overheating of the melt and affect the extrusion effect.
2. Equipment parameters
Temperature setting: The temperature in different areas of the extruder has different effects on the extrusion effect. If the temperature of the front section of the barrel is too high, the PVC melt may be scorched; if the temperature is too low, the PVC plasticization is incomplete.
Screw speed and pressure: The screw speed determines the conveying and plasticization efficiency of PVC raw materials. If the speed is too fast, the raw material stays in the barrel for a short time, the plasticization is incomplete, and there will be unmelted particles on the surface of the extruded profile; if the speed is too slow, the production efficiency will be reduced. At the same time, the rotation of the screw will generate pressure, and the appropriate pressure can ensure that the melt is extruded evenly through the mold. If the pressure is unstable, the wall thickness of the extruded rain gutter may be uneven.
Mold structure and precision: The shape of the mold determines the cross-sectional shape of the extruded rain gutter. If the internal structure of the mold is not designed properly, such as dead corners in the flow channel or an uneven surface, it will cause uneven melt flow and local defects in the extruded profile, such as irregular edges or stress concentration points inside. The dimensional accuracy of the mold is also very important. Dimensional deviations will directly lead to the extruded rain gutter size not meeting the requirements.
If you are deeply interested in the factors that affect the extrusion effect of PVC Gutter Extruder, please contact East Point Machinery. Our professional team will provide you with tailor-made solutions and comprehensive technical support.