Reasons Why Conical Twin-Screw Extruder Barrels and Screws Require Maintenance

Conical twin-screw extruders feature a large feeding area, a high compression ratio, superior material shearing and mixing efficiency (both longitudinally and laterally), and excellent plasticizing capabilities. Consequently, they are particularly well-suited for producing plastic profiles from high-calcium-filled PVC powder.

However, the high-efficiency production capabilities of these extruders often lead to challenges regarding the service life of their barrels and screws:

1. Inorganic calcium carbonate-which has significant particle size and high hardness-is often added at ratios as high as 150%, and recycled plastics containing various impurities are frequently used as primary raw materials. The barrels and screws struggle to withstand the solid-phase friction generated by these materials.

2. To achieve superior plasticizing performance, the material is forced from the large feed opening toward the smaller discharge end-a design known as "super-conical." This intensifies solid-phase friction, causing particularly severe wear at the narrow end of the barrel and the small-diameter section of the screw. Furthermore, the screw is subjected to higher back pressure than those in standard single-screw or parallel twin-screw extruders.

3. Corrosion of the barrel and screw caused by chloride ions released during the plasticizing process, among other factors, represents a critical issue that cannot be overlooked when considering the service life of these core components.