How to prolong the service life of PVC extrusion equipment

Equipment Material Selection and Structural Optimization

1. Xinhe utilizes reinforced screws and barrels.

   • Use 38CrMoAl nitrided steel screws with a surface nitrided layer ≥0.7mm thick and a hardness of 950-1020HV, significantly improving wear resistance.

   • Based on the processing characteristics of PVC, it is recommended to use a double-layer composite process (e.g., H13 steel substrate + tungsten carbide coating) in the feeding and melting sections to mitigate wear caused by high-filled calcium carbonate.

2. Mold Design Improvement

   • The die lip clearance accuracy is controlled within ±0.05mm, and the die-forming section length should be 10%-30% of the product thickness to avoid melt retention and material decomposition.

   • The diverter cone angle must be <60° to prevent melt retention and thermal degradation of PVC.

   • Based on conventional molds, Xinhe has developed high-speed molds using three sections, such as high-speed molds for ceilings, high-speed molds for corner lines, and high-speed molds for PE pipes.

II. Precise Control of Process Parameters

1. Temperature Gradient Management:

   • Feeding zone: 185-195°C (to ensure rapid vitrification of the powder), compression zone: 180-195°C, melting zone: 180-190°C, metering zone: 170-180°C (to avoid overheating and decomposition of the melt).

   • Die zone temperature: 190-210°C. Balance internal shear heat by adjusting brightness and extrusion pressure.