In the extrusion sector, the question seems natural: "Why can't we have a universal screw that works with any polymer?". The answer lies in the intrinsic complexity of polymer materials and their properties. Each polymer has unique characteristics that require a targeted design approach to achieve the best results in terms of efficiency and quality.

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Key Differences Between Polymers

Every extrusion screw performs three main functions: transporting solids, melting, and pumping the material. These processes are strongly influenced by the specific properties of polymers, including:

• Thermal Characteristics: Polymers like rigid PVC and flexible PVC have different energy requirements and melting points. For example, rigid PVC generally requires 20-30% more energy to reach its processing temperature compared to flexible PVC.
• Viscoelastic Properties: The material's viscosity varies with shear stress and temperature. Rigid PVC typically exhibits higher viscosity values compared to flexible PVC, requiring different screw configurations to optimize melting and productivity.
• Density and Compression: Flexible PVC generally has a lower melt density compared to rigid PVC, necessitating an appropriate compression ratio to maintain production capacity.

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A Complex Balance

Each property of the polymer affects screw design, making it impossible to develop a universal solution. For instance, a screw optimized for polymers with low gelation energies would not ensure the complete melting of materials with high gelation energy, compromising the quality of the final product.

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The Key Is Adaptability

Through targeted design, it is possible to develop highly efficient screws for specific polymers, maximizing efficiency and reducing waste. Additionally, once an optimal design is defined, it can be adapted to different screw sizes using scaling ratios, maintaining the same operational effectiveness.

In conclusion, the variety of polymer properties is what makes our industry so stimulating and ever-evolving. Designing the right screw for each material is not just a challenge but also an opportunity to ensure excellent results and tailored solutions.

If you would like to learn more about optimizing your production line based on the materials you use, please feel free to contact us. We are here to support you with our expertise and technical competence.