Brief summary
In this article we will explore the world of the design and principal functions of screws for plastic extrusion. Let’s find out how these key elements affect the quality and efficiency of the process by playing a crucial role in obtaining high-quality plastic products through an innovative and targeted approach.
Design and functionality of screws for extrusion
One fundamental aspect when it comes to optimizing the plastic extrusion process is the design of the extruder’s screw. This critical element – used to create a wide range of products – directly influences the quality and efficiency of the extruder. The choice of screw design for plastic extrusion depends on the needs of the application. The right selection can make the difference in the yield and efficiency of the process.
Familiarity with the characteristics, benefits, and uses of each type of screw design helps producers make useful informed decisions and optimize their plastic extrusion process to meet the specific needs of the sector.
The seven most common types
The key role of screws in plastic extrusion is to provide a superior quality plasticized polymer. In this sense, as we have already said, the careful selection of the material and profile of the screw is key to ensuring optimum long-term performance. The choice of screw type depends on various factors, including:
Designers and engineers therefore have to carefully assess these factors to choose the screws most suited to their needs. To overcome the design challenges of extruder screws, they use advanced numerical simulations based on Computational Fluid Dynamics (CFD), Finite Element Method (FEM), and Discrete Element Method (DEM). The use of CAE software that incorporates these techniques improves design reliability and makes it easier to predict operating conditions. There are different types of screw designs for plastic extrusion.
Let’s look at the seven most common:
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Dual Flight Screws: this type of screw has two helix pitches with different lengths that can improve the consistency of the fusion and the transport capacity of the materials.
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Barrier Screws: these screws include a section with a barrier, which helps better control the temperature and mixing of the material during extrusion.
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High-Speed Screws: designed to work at high speeds, these screws promote rapid fusion and more efficient material advancement.
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Mixer Screws: these screws are designed with additional mixer elements to guarantee uniform distribution of color or other additives in the molten material.
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Screwless or Barrier-Free Screws: this design eliminates the screw barrier to reduce stress on the material and improve the quality of the extrusion.
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Screws for special materials: some plastic materials require specific screw designs to tackle their unique characteristics. For example, screws with special coatings may be required to deal with abrasive or corrosive materials.
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Cold Feed Screws: these screws are designed for extruding rubber and elastomeric materials at low temperatures.
Longer lifespan: choose Bausano screws for flawless production
Mechanical components and the majority of engineering systems that include moving parts can malfunction and degrade in performance due to wear and tear.
Strive for maximum reliability in your plastic extrusion production!
Bausano screws, coated in hard metal (such as stellite), are resistant to wear and tear, guaranteeing a longer lifespan. Protect your investment and avoid costly production interruptions.
