Temperature Parameters
The extruder barrel features zoned temperature control: the feed section is set to 150–190°C, the die head section reaches up to 200–235°C, and the melt temperature is stabilized at 190–230°C. Cooling water temperature is maintained at 15–25°C to prevent pipe deformation or residual internal stress.
Screw and Speed Parameters
The extruder screw requires a length-to-diameter (L/D) ratio of at least 20:1 (24:1 is recommended), utilizing a metering section design with a low compression ratio and deep screw flights. Screw speed is controlled between 20 and 60 rpm to avoid material degradation caused by excessive shear heat.
Pre-treatment Parameters
TPE raw materials are hygroscopic; they must be dried at 80°C for 2–3 hours prior to processing to keep moisture content within safe limits, thereby preventing defects such as bubbles or silver streaks in the pipe.
Other Auxiliary Parameters
A vacuum degassing system is employed to eliminate bubbles in the melt. The haul-off speed is matched to the extrusion speed to ensure uniform wall thickness and maintain dimensional tolerances within ±0.2 mm.
