Selection method of plastic extruder screw
by：TENGDA
2023-01-03
The screw of the plastic extruder is the core part of the injection device. The conveying, mixing, plasticizing and injection of materials are all carried out under the action of the extrusion screw.
At present, new types of screws are constantly emerging, and the screw structure is developing in the direction of high efficiency and low energy consumption. Screw selection focuses on structural form, model, and specification. The basis for selection is output, quality, energy consumption, processability, life and economy.
(1) Ordinary screw
Ordinary screw has simple structure and low cost, but its plasticization and uniformity are poor, so it is not suitable for difficult-to-process plastics. For non-crystalline m material, plastic melting is completed in a relatively large temperature range (such as the softening temperature of rigid polyethylene is 75-165 ° C), therefore, it is more appropriate to choose an equidistant gradient screw. For crystalline plastics, because there is no obvious high elastic state before the temperature rises to its melting point, that is, its softening degree is narrow (such as the softening point of high-pressure low-density polyethylene is 83-111°C), so it is generally used. distance from the mutant screw.
(2) New screw
A few days ago, there are more than 200 new types of screws researched and developed at home and abroad, all of which are to ensure the conveying capacity of the plastic extruder by adding mixing elements to the homogenization section of the ordinary screw or by other methods to improve the product yield. Fair and quality and reduce energy consumption, improve efficiency.
Commonly used new screws are:
1. The common structural feature of the splitter screw is to mill out a boss or install a mirror nail on the screw, and open a diversion groove or a diversion hole. The model assembled with this screw has high plasticizing efficiency, good mixing uniformity and good product quality, and has been widely used in China and abroad.
2. The structural feature of the barrier type cricket is that a 'barrier' is set at a certain position on the screw to achieve the purpose of hindering the passage of the solid phase of the material and promoting the melting of the solid phase. One of the simplest is to configure a barrier-type mixing element at the head of the common screw. Mainly used for polyolefin materials.
3. The structural feature of the variable channel screw is that the cross-sectional shape or cross-sectional area of the screw channel is a variable angle. Its representative is the corrugated screw. Due to the frequent compression, shearing and relaxation of this screw, it is not suitable for processing heat-sensitive plastics. Although the double flute screw is difficult to process and manufacture, it has good plasticizing and mixing quality, and is suitable for difficult-to-process plastics, and the plasticizing efficiency of the plastic extruder is high.
(3) Wear-resistant and corrosion-resistant screw
The wear-resistant and corrosion-resistant screw is hard chromium-plated on the surface of the screw (especially effective against the corrosion of atmosphere compounds), sprayed or surfacing, wear-resistant or wear-resistant and drink-resistant hard alloy, such as drill plug alloy, nickel-based alloy or carbide Tungsten, etc., and matched with the wear-resistant and corrosion-resistant bimetallic cylinder, form a pair of good friction pairs, which are suitable for the processing of inorganic fillers with strong wear in polymers, such as glass fiber, or where corrosive decomposition products are easily produced. Plastic processing.
Currently there is a global trend growing. People are more conscious about plastic extruder machine manufacturers and are seeking alternatives to traditional solutions.
For many years, Nanjing Tengda Machinery Co., Ltd. has searched for and found a number of secrets to help you extruder machine manufacturers. Go to TENGDA Extruder Machine Manufacturers to learn about some of those secrets.
Nanjing Tengda Machinery Co., Ltd. believes that the average profitability will be sufficient.
At present, new types of screws are constantly emerging, and the screw structure is developing in the direction of high efficiency and low energy consumption. Screw selection focuses on structural form, model, and specification. The basis for selection is output, quality, energy consumption, processability, life and economy.
(1) Ordinary screw
Ordinary screw has simple structure and low cost, but its plasticization and uniformity are poor, so it is not suitable for difficult-to-process plastics. For non-crystalline m material, plastic melting is completed in a relatively large temperature range (such as the softening temperature of rigid polyethylene is 75-165 ° C), therefore, it is more appropriate to choose an equidistant gradient screw. For crystalline plastics, because there is no obvious high elastic state before the temperature rises to its melting point, that is, its softening degree is narrow (such as the softening point of high-pressure low-density polyethylene is 83-111°C), so it is generally used. distance from the mutant screw.
(2) New screw
A few days ago, there are more than 200 new types of screws researched and developed at home and abroad, all of which are to ensure the conveying capacity of the plastic extruder by adding mixing elements to the homogenization section of the ordinary screw or by other methods to improve the product yield. Fair and quality and reduce energy consumption, improve efficiency.
Commonly used new screws are:
1. The common structural feature of the splitter screw is to mill out a boss or install a mirror nail on the screw, and open a diversion groove or a diversion hole. The model assembled with this screw has high plasticizing efficiency, good mixing uniformity and good product quality, and has been widely used in China and abroad.
2. The structural feature of the barrier type cricket is that a 'barrier' is set at a certain position on the screw to achieve the purpose of hindering the passage of the solid phase of the material and promoting the melting of the solid phase. One of the simplest is to configure a barrier-type mixing element at the head of the common screw. Mainly used for polyolefin materials.
3. The structural feature of the variable channel screw is that the cross-sectional shape or cross-sectional area of the screw channel is a variable angle. Its representative is the corrugated screw. Due to the frequent compression, shearing and relaxation of this screw, it is not suitable for processing heat-sensitive plastics. Although the double flute screw is difficult to process and manufacture, it has good plasticizing and mixing quality, and is suitable for difficult-to-process plastics, and the plasticizing efficiency of the plastic extruder is high.
(3) Wear-resistant and corrosion-resistant screw
The wear-resistant and corrosion-resistant screw is hard chromium-plated on the surface of the screw (especially effective against the corrosion of atmosphere compounds), sprayed or surfacing, wear-resistant or wear-resistant and drink-resistant hard alloy, such as drill plug alloy, nickel-based alloy or carbide Tungsten, etc., and matched with the wear-resistant and corrosion-resistant bimetallic cylinder, form a pair of good friction pairs, which are suitable for the processing of inorganic fillers with strong wear in polymers, such as glass fiber, or where corrosive decomposition products are easily produced. Plastic processing.
Currently there is a global trend growing. People are more conscious about plastic extruder machine manufacturers and are seeking alternatives to traditional solutions.
For many years, Nanjing Tengda Machinery Co., Ltd. has searched for and found a number of secrets to help you extruder machine manufacturers. Go to TENGDA Extruder Machine Manufacturers to learn about some of those secrets.
Nanjing Tengda Machinery Co., Ltd. believes that the average profitability will be sufficient.
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