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What is Screw Barrel?

Views: 90     Author: Site Editor     Publish Time: 2022-03-24      Origin: Site

Structure of screw barrel

A screw barrel is a set made up of screw and barrel.

It forms the core part of plastic processing machinery. The screws are made of high-quality material since they are prone to wear due to friction. The barrels are also designed to be compatible with the screws. They are hardened through nitrification, and this increases their durability. Barrels have two openings at both ends.

One end is the material entry point, while the opposite is the output end. Accuracy in measurements is critical in the manufacture of screws and barrels. They are customized to meet the customers' preferences. There are many types of screw barrels manufactured for various reasons.

The screw has rotations made in the correct direction to allow the processed material's forward movement. There is a small gap between the top of the screw and the interior side of the barrel. This ensures that the material does not fall off the screw's root. The length of the barrel is similar to that of the screw. However, depending on the type of screw barreL the screw diameter varies.

A single screw barrel has a feed zone, compression zone, metering, and a mixing zone. The feed zone is found at the back of the screw; where the diameter is fixed. The diameter increases at the compression zone. Along the length of the barrel are heater bands that facilitate the melting of the material. The screw barrel also has a section known as the hopper; which stores the materials for a period of time. The hopper has a cutting device at the bottom and a metering section where calibration is done.


Working principle of a screw barrel

The screw barrel is divided into feeding, compression, metering, and mixing phases. As the name suggests, the feeding zone is the material entry point. The plastic material is taken from the hopper and transferred into the next stage at this site. The friction force between the barrel and the material is made solid and stable to improve the feeding phase.

The compression phase has a heat source and compresses the material. The air and water obtained from the material are channeled back to the feeding zone. This makes the remnant solid material sticky and soft. The methods used to compress the materials depend on the type of screw barrels.

Following the compression phase is the metering section. The material is extruded at a set pressure in this phase. This leads to the formation of a homogenous material that is transferred to the mixing stage. Mixing helps in improving the uniformity of the material being processed.

The material passes through a section with a specific conformation and size where it is shaped. Finally, the material cools, forming a shaped product.


Features of screw barrel

The screw barrels are designed for specific functions. Their features help them to perform their duties. First and foremost, the screw and the barrel measurements are accurate. This allows compatibility of the screw and the barrel. The parts also make corrosion accessible by using alloys to drive the screws and barrels. This increases the service life of the screw barrel.

Due to the movement of the screws, friction is expected and thus causing quick wear of metals. However, the materials are hardened through the nitrification process. In this process, they are thickened and made heat stable. As a result, the parts are durable and thus reducing the maintenance cost.


Material of screw barrel

The screws and barrels are made of hardened steel. The use of steel ensures that the machine does not rust. Various alloys are also used to make the barrels and screws, and other elements. Nickel, tungsten, and their alloys are used as raw materials. The materials used to make the screw barrel make it durable and easy to maintain.


Applications of screw barrel

When designing the screw barrel, the intended intention is first determined. Those used in a plastic factory are different from those found in food processing industries. The screw barrel is widely used in the plastics processing industry. It is the primary machine used to make plastics such as PVC pipes. It is also used in the food processing industry. In such factories, the extruders are used to create a wide variety of food products. The screw barrel is also used in making cables. Some types of extruders are used to produce small materials, such as in testing departments in specific industries.


Types of screw barrels

Screw barrels are an integral part of the plastics manufacturing industry. They are made up of a screw and barrel, primarily produced. There exist various types of screw barrels in the industry. This article will provide a short but thorough detail about our company's various types of screw barrels


1. Twin Screw Barrel

They are manufactured using high-quality stainless steel. Advanced technology has been employed in making these twin-screw barrels. This makes them resistant to corrosion, and therefore, they do not rust. Multiple heat treatment such as nitriding improves the quality of these screw barrels. The material type increases the duration of service for this equipment. The dimensions are made as accurate as possible for compatibility. There are two types of twin-screw barrels.


2. Parallel Twin Screw Barrel

It is used in the modification and filling of plastics. The axis of the twin-screw is parallel and thus its name. In addition, the twin screws have the same diameter and a reasonable structure design of the screw. As a result, the parallel-twin screw barrel can bear a large load, consuming less energy.


3. Conical Twin Screw Barrel

The diameter of these screw barrels differs, and thus there is a small end and a large end. Both of the axes of the conical twin screws are placed at an angle. It is majorly used for making PVC, such as pipes and sheets. The designs can easily be customized according to the required formulations.

The twin-screw barrels have various elements that have critical functions. The screw elements for twin-screw extruders are readily available in the company at affordable prices. There are various types of elements. A conveying screw element is an example which is an extruder screw component that has an opening on the longitudinal side. They have a reliable self-cleaning feature enabling them to create high pressure in a short axial distance. Kneading screw element is another type that is a vital part of the rotating twin screw extruder. A kneading block acts as the melting site.


4. Injection Screw Barrel

These are used for injection mold machines. They are exposed to high pressure, and thus their stability is crucial during the manufacturing process. They are used in the food processing industries and cable manufacturing machines. The suitable injection molding screws should be used for the best quality output.


5. Extruder Screw Barrel

They are widely used during plastic extrusion when making pipes and tubes. They are found in various measurements depending on the compatibility of the machines involved. The screws are of high strength and thus their efficiency. In addition, they are made of stainless steel increasing their service life and reducing maintenance costs.


6. Rubber Screw Barrel

The rubber screw barrel is designed to withstand extreme pressure and temperatures and thus have high mechanical strength. This is because the screw of the extruder rotates inside the barrel under a high temperature and pressure. It is also able to withstand friction during the movement. For proper maintenance, the temperatures should be regulated. This minimizes the destruction of the rubber component during the process of extrusion. Tungsten alloy surface spraying is used in making this screw barrel to increase performance.


7. Bimetallic Screw Barrel

It is made up of a high heat resistant alloy reducing the chances of wearing out. As the name suggests, two metals are used in manufacturing them. Other types of screw barrels can be bimetallic. They have a variety of sizes of their screws. Nitriding is done to harden these metals enough to perform their duty. It also reduces corrosion since a dense layer is formed. Choosing a screw barrel made by a bimetallic material reduces the maintenances.


8. Planetary Screw Barrel

The planetary system has a hollow barrel a significant screw; and many small diameter screws. It is majorly used for materials that are sensitive to heat. The structure of the screw can easily be customized depending on the customer's preference. When the material is allowed to pass through the small-diameter screws, it is exposed to high tensile action, thus improving the mixing property. The diameter ranges from 70mm- 190mm, while the nitride thickness lies between 0.5mm and 0.8mm.


9. XPS Foamed Screw Barrel

This screw barrel is useful for XPS foam boards, sheets, and insulation tubes. The foaming agents used include carbon dioxide, butane, and freon gas. Screw diameters range from 15mm to 300mm, similar to the barrel's inner diameter. As with the other screw barrels, a nitride layer is present with a thickness of 0,5mm- 0.8mm for hardness and durability.


10. Segment Screw Barrel

There are various designs of the segment screw barrel. The quality of the plastics is dependent on the segment screw's quality. When these screws are of high quality, the best performance, such as coloring and mixing, is achieved. They are made of nickel-based or copper-based alloys, thus promoting their durability.


All these types of screw barrels are available at our company. The product description is also available on our website. We assure the quality and customization of our products. Thank you.






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