Screw shearing under high temperature and high pressure: How to improve the product strength and toughness of WPC extrusion production line?

In the working environment of WPC extrusion production line, high temperature and high pressure are two indispensable conditions. High temperature can reduce the viscosity of the material, making it easier to flow and mix; while high pressure ensures the tightness and stability of the material during the extrusion process. Under the combined effect of these two conditions, the material begins to enter the plasticization stage, laying a solid foundation for subsequent product molding.

In the WPC extruder, the screw is the core component of the plasticization process. It shears, stretches and compresses the material by rotating under high temperature and high pressure, thereby achieving plasticization and mixing of the material. The design of the screw, including its length, diameter, pitch, screw groove shape, etc., directly affects the intensity and effect of the shearing action.

1. Shearing action
The shearing action of the screw mainly occurs in the screw groove. When the screw rotates, the material is brought into the screw groove and is subjected to strong shear force in the narrow space between the screw and the barrel. This shear force can destroy the original molecular structure of the material, forming new and smaller molecular segments, thereby increasing the fluidity and plasticity of the material.

2. Stretching and compression
In addition to the shearing action, the screw also stretches and compresses the material through its special configuration design. In some areas of the screw, the material is stretched into a slender fiber, while in other areas, it is strongly compressed to form a dense material layer. This alternating action of stretching and compression further promotes the mixing and plasticization of the material.

The synergistic effect of high temperature and high pressure environment and the shearing action of the screw is the key to the efficient plasticization of the WPC extrusion production line. At high temperature, the viscosity of the material decreases and the fluidity increases, making it easier for the screw to shear and mix the material. The high pressure ensures the tightness and stability of the material during the extrusion process, avoiding the generation of bubbles and voids.

The shearing action of the screw also promotes the plasticization process of the material at high temperature. Through mechanical actions such as shearing, stretching and compression, the screw cuts the macromolecular segments in the material into smaller molecular segments, which are more likely to rearrange and cross-link at high temperatures, thereby forming a more stable and dense molecular structure. This structural change not only improves the strength and toughness of the product, but also gives the product better heat resistance, weather resistance and corrosion resistance.

The screw shearing effect under high temperature and high pressure has a significant impact on the performance improvement of WPC extrusion production line products.
1. Improvement of strength and toughness
As mentioned above, the shearing effect of the screw promotes the plasticization process of the material at high temperature and forms a more stable and dense molecular structure. This structural change has significantly improved the strength and toughness of the product. In practical applications, this improvement enables WPC materials to better withstand external forces and is not prone to breakage or deformation.

2. Enhanced heat resistance and weather resistance
Due to the stable molecular structure formed by the screw shearing effect, the products produced by the WPC extrusion production line have also been significantly improved in terms of heat resistance and weather resistance. This improvement enables WPC materials to maintain stable performance at higher temperatures and are not prone to thermal deformation or thermal decomposition; at the same time, they can maintain good performance stability under harsh climatic conditions such as high temperature, low temperature, humidity, etc.

3. Improved processing performance
The screw shearing effect under high temperature and high pressure also improves the processing performance of WPC materials. By optimizing the design parameters and process conditions of the screw, precise control of the material plasticization process can be achieved, thereby producing products with specific properties and shapes. This flexibility and controllability enables WPC materials to better meet customer needs and expectations during processing.

Although the shearing action of the screw under high temperature and pressure plays an important role in the WPC extrusion production line, it still faces some challenges in actual application. For example, the wear and corrosion of the screw, the retention and clogging of the material in the screw, and the adjustment of the gap between the screw and the barrel all need to be carefully studied and solved.

In order to solve these problems, the industry is constantly exploring new screw materials and design technologies to improve the wear resistance and corrosion resistance of the screw; at the same time, it is also optimizing the structure and process parameters of the extruder to reduce the retention and clogging of the material in the screw; in addition, the gap between the screw and the barrel is precisely controlled to ensure the stability and continuity of the material during the extrusion process.