Bimetallic Twin Screw Cylinder: Enhancing Performance And Efficiency

bimetallic twin screw cylinder

Bimetallic twin screw cylinders are used in the manufacturing industry for a variety of applications, including plastics, food, and rubber. They are made by bonding two or more metals together, typically a high-wear resistance alloy and a high-corrosion resistance alloy, to create a durable and efficient tool. The process of making a bimetallic barrel involves filling a steel tube with powdered metal, heating it to melt the metal, and then evenly distributing the melt through rotation. Bimetallic twin screw cylinders offer improved wear resistance, increased strength, better mixing and melting capabilities, and longer lifespans compared to traditional tools. They are customisable and can be used for wood-plastic composites, polymer compounding, food processing, pharmaceuticals, and recycling.

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Bimetallic barrels for extruder feed screws

One of the key advantages of bimetallic barrels is their ability to withstand challenging materials, such as recycled plastics or PVC, which can be harsh on extruder machines. The tungsten carbide coating, with a hardness of 62-70 RC, provides a smooth production process even when using these difficult-to-work-with materials. This coating is applied using a PTA spraying system, resulting in a thickness of approximately 0.8-2 mm, depending on the specific application.

The use of bimetallic barrels offers significant cost savings for manufacturers. By utilising recycled or off-spec plastics, producers can reduce their raw material costs while maintaining the quality of their pipes. Additionally, the durability of the bimetallic barrels contributes to cost savings by reducing the need for periodic maintenance and replacement of parts.

Xaloy® X-800 bimetallic barrels, for instance, have proven to significantly outlast nitrided barrels when processing rigid PVC, vinyl materials, and plastic-wood composites. The X-800 barrels are lined with a composite of tungsten carbide particles dispersed in a nickel alloy matrix, providing superior resistance to abrasive fillers and corrosive volatiles. This technology ensures optimal performance and extended service life for extruder machines, making them a reliable choice for manufacturers.

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Bimetallic screw element for wood plastic extruders

Bimetallic extruder screw elements for wood plastic extruders are designed to improve the performance and durability of the extrusion process. This is achieved by combining two different metals, each with their own unique properties, to create a single, more effective, piece of equipment.

Bimetallic screw elements are typically made by bonding a steel core with a layer of tungsten carbide on the surface. The steel provides strength and durability, while tungsten carbide offers wear resistance and extends the life of the screw element. This combination is particularly useful when working with wood fibres and other abrasive materials. By using a bimetallic screw element, manufacturers can improve the mixing and dispersion of wood fibres or particles in the plastic matrix, resulting in a more consistent and homogeneous product.

Bimetallic screw elements are also beneficial in twin screw extruders, which use two screws that rotate in opposite directions to mix and melt materials. In this application, bimetallic screw elements improve the conveying and melting of polymer materials, as well as the mixing and homogenization of additives and fillers. The use of bimetallic screw elements in twin screw extruders can lead to improved productivity, reduced downtime, and longer service life.

Furthermore, bimetallic screw elements offer customizable options to meet specific application needs. Different metals or coatings can be used to optimize the mixing and melting process. This versatility makes bimetallic screw elements suitable for a wide range of industries, including wood-plastic composites, polymer compounding, food processing, and pharmaceuticals.

Overall, the benefits of bimetallic extruder screw elements for wood plastic extruders include improved wear resistance, increased strength and durability, better mixing and melting capabilities, longer lifespans, and customizable options. These advantages contribute to improved efficiency and performance in the extrusion process, resulting in higher-quality products.

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Bimetallic twin barrels for processing PVC

Bimetallic twin barrels are used in the processing of PVC to enhance performance and increase output efficiency. The use of two metals in the barrel's construction offers several advantages over traditional nitrided barrels.

One of the key benefits of bimetallic twin barrels is their durability. The fusion of two different metals in a high-temperature furnace creates a super-hard and highly uniform lining. This process, employed by manufacturers like WEXCO, results in excellent cylinder performance and a long service life. Bimetallic barrels have been proven to far outlast nitrided barrels when processing rigid PVC, vinyl materials, and plastic-wood composites.

The composition of bimetallic barrels also provides superior resistance to abrasive fillers and corrosive volatiles. This is especially critical in counter-rotating twin-screw extrusion due to the high screw-to-barrel loading and the potential for adhesive and abrasive wear. The tungsten carbide composite used in Xaloy® X-800 barrels, for instance, offers exceptional resistance to these issues.

Bimetallic twin barrels also offer customisation options to meet specific processing requirements. Manufacturers like WEXCO offer various cylinder-lining alloys, including general-purpose iron/boron alloy and nickel/tungsten carbide alloy, which provide different levels of abrasion and corrosion resistance. This flexibility ensures that the barrels can be tailored to the specific needs of PVC processing.

Additionally, bimetallic twin barrels provide cost-effectiveness and convenience. For instance, Xaloy offers relining services for worn nitrided barrels, which can extend their lifespan at a lower cost than complete barrel replacement. This relining process involves boring out the nitrided lining and fitting a new twin liner, ensuring proper heating and cooling of the plastic during processing.

Overall, bimetallic twin barrels offer significant advantages in the processing of PVC, including enhanced durability, resistance to wear and corrosion, customisation options, and cost-effectiveness. These benefits contribute to improved output efficiency and superior end-product quality.

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Bimetallic protective layer

Bimetallic barrels are used in extruder feed screws and are made of high-alloy steel. They are often used as a low-cost replacement for plastics and food processing machinery. The bimetallic treatment can include hard chroming or a sprayed-on hard alloy.

One example of a bimetallic barrel is the Xaloy® X-800, which is lined with a composite of superhard tungsten carbide particles in a nickel alloy matrix. This product has proven to be more durable than nitrided barrels when processing rigid PVC, other vinyl materials, and plastic-wood composites. The Xaloy® X-800 also offers greater resistance to abrasive fillers and corrosive volatiles.

The bimetallic protective layer of the Xaloy® X-800 barrel is achieved through a spin-casting process and proprietary joining methods. This process involves boring out the existing nitrided lining and fitting a new twin liner with a bimetallic tungsten carbide composite inlay. This custom-fit process ensures proper heating and cooling of the plastic during processing.

Another option for bimetallic treatment is a tungsten carbide coating applied using a PTA spraying system. This method bonds the coating to the base material, with a thickness of approximately 0.8-2mm and a hardness of 62-70 RC.

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Bimetallic screw element for polymer compounding

Bimetallic screw elements are used in polymer compounding processes to improve the mixing and melting of different polymers and additives. This is achieved by bonding two or more metals together to create a single piece of equipment, combining the benefits of each metal. For example, a bimetallic screw element might have a steel core for strength and durability, with a layer of tungsten carbide on the surface for wear resistance and an extended lifespan.

Twin screw extruders use two screws that rotate in opposite directions to mix and melt materials. Bimetallic screw elements can be customised to meet the specific needs of these applications, such as using different metals or coatings to optimise performance. They can also be used in wood plastic extruders to improve the mixing and dispersion of wood fibres or particles in the plastic matrix, resulting in a more homogeneous and consistent product.

Bimetallic screw elements offer improved wear resistance, increased strength and durability, better mixing and melting capabilities, and a longer lifespan. They can also be customised to meet specific application requirements, such as using different metals or coatings to optimise performance. This makes them ideal for use in various industries, including wood-plastic composites, polymer compounding, food processing, pharmaceuticals, and recycling.

The use of bimetallic screw elements can lead to improved productivity and reduced downtime, as well as lower maintenance costs due to their longer service life. They are a popular choice for improving the performance and longevity of extruders in a range of applications.

Frequently asked questions

A bimetallic twin screw cylinder is a type of barrel used in extrusion processes that is made by bonding two metals together to create a single piece of equipment. This is done to combine the beneficial properties of both metals.

Bimetallic twin screw cylinders offer improved wear resistance, increased strength and durability, better mixing and melting capabilities, and a longer lifespan when compared to traditional nitrided barrels.

Bimetallic twin screw cylinders typically use a combination of high-wear resistance alloys and high-corrosion resistance alloys, such as tungsten carbide and nickel alloy. The base material is often high-quality 38CrMoAlA steel.

Bimetallic twin screw cylinders are used in a variety of industries, including plastics, food processing, pharmaceuticals, and recycling. They are commonly used for processing PVC, vinyl materials, plastic-wood composites, and wood-plastic composites.

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