The main machine of the plastic extruder is the extruder, which is composed of an extrusion system, transmission system, and heating and cooling system. The following is a detailed description of the composition of the plastic extruder.
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Heating and cooling device
A homogeneous melt is plasticized bypassing the plastic through the extrusion system, which consists of a screw, barrel, hopper, head, and die.
The function of the drive system is to drive the screw, supplying the torque and speed required by the screw during the extrusion process, usually consisting of an electric motor, reducer, and bearings.
The manufacturing cost of the reducer is roughly proportional to its size and weight, provided that the structure is the same. Because the shape and weight of the reducer are large, it means that more materials are consumed in the manufacturing, and the bearings used are also larger, which increases the manufacturing cost.
For a similar screw diameter extruder, the high speed and high potency extruder consume additional energy than the traditional extruder, the motor power is doubled, and also the reducer seat range is raised consequently is critical，however a high screw speed means that an occasional reduction magnitude relation. For the same size reducer, the gear modulus of the low reduction ratio increases compared to the large reduction ratio, and the capacity of the reducer to bear the load also increases. Therefore, the rise in volume and weight of the reducer isn't linearly proportional to the rise in motor power. If the extrusion volume is employed because of the divisor and dividend by the burden of the reducer, the high speed and high potency extruder can have a smaller range and the normal extruder will have a larger number.
In terms of unit output, the small motor power and the small weight of the reducer of the high speed and high-efficiency extruder means that the manufacturing cost per unit output of the high speed and high-efficiency extruder is lower than that of the normal extruder.
Heating and cooling are necessary to enable the plastic extrusion process to proceed.
(1) Extruders usually use electric heating, which is divided into resistance heating and induction heating, with heating sheets installed in each part of the body, neck, and head. The heating device heats the plastic inside the barrel from the outside to warm it up to the temperature required for the process operation.
(2) The cooling device is installed to ensure that the plastic is in the temperature range required for the process. Specifically, it is to exclude the excess heat generated by the shear friction of the rotating screw to avoid the plastic from decomposing, scorching, or shaping difficulties due to the high temperature. Barrel cooling is divided into two kinds of water-cooled and air-cooled, generally small and medium-sized extrusion machine using air-cooled is more appropriate, large is more water-cooled or a combination of two forms of cooling; screw cooling is mainly used in the center of water-cooled, the purpose is to increase the rate of solid material delivery, stabilize the amount of rubber, while improving product quality; but the cooling at the hopper, one is to strengthen the role of solid material delivery, to prevent the plastic grain sticky blockage because of the heating the second is to ensure the normal work of the transmission part.
If you are engaged in the industry related to the extruder, you can consider our cost-effective products. Our company is a leading extruder manufacturer specializing in a twin-screw extruder, micro twin-screw extruder, plastic extruder, and parallel twin-screw extruder in China.
Twin screw extruder is developed based on the single screw extruder, which has been widely used in the molding process of extruded products because of its good feeding performance, mixing and plasticizing performance, exhaust performance, and extrusion stability. So what are the advantages of a twin screw extruder? The following is a detailed introduction.
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l Wear and tear
l Reduce production costs
l Increase output
l Improve labor efficiency
l High torque and high speed
Wear and tear
Since twin screw extruders are easy to open, the degree of wear of threaded elements and barrel bushings can be detected at any time, so that effective repair or replacement can be carried out. It is not necessary to find out only when there is a problem with the extruded product, which causes unnecessary waste.
Reduce production costs
When producing masterbatches on twin screw extruders, it's usually necessary to alter colors, and if a product amendment is critical, to open the open process space within several minutes, in addition to analyzing the mixing process by looking at the melt profile on the entire screw. The current common twin screw extruder needs to be cleared with a large amount of clearing material when changing colors, which is time consuming, power consuming, and a waste of raw material. The split twin screw extruder can solve this problem. When changing the color, it only takes a few minutes to quickly open the barrel for manual cleaning, so that no or less cleaning material can be used, saving costs.
Twin screw snack extruders use side feeding technology to improve the integrity of the material and greatly increase production. The position and shape of the feed opening also have a great influence on feeding efficiency. With the same parameters, the output increases with an increase in the feed area. A rectangular cross section has a higher feed efficiency than a circular cross section for the same inlet area. The use of side by side twin screw feeds is also based on this consideration.
Improve labor efficiency
During equipment maintenance, ordinary twin screw extruders often have to remove the heating and cooling system before the screw can be withdrawn as a whole. In contrast, the split twin screw does not need to be opened by loosening a few bolts and turning the worm gearbox handle device to lift the upper half of the barrel, and then the entire barrel can be repaired. This shortens the maintenance time and reduces the labor intensity.
High torque and high speed
At present, the event trend of twin screw extruders within the world is to develop within the direction of high torsion, high speed, and low energy consumption, and also the impact of high speed is high productivity. The split twin screw extruder belongs to the current class, and its speed will reach and five hundred revolutions per minute. Therefore, its distinctive benefits in process high viscousness and warmth sensitive materials.
In the high speed, high torque core technology, asymmetric and symmetric high torque gearbox currently only Germany and Japan related manufacturers master the core technology, its speed can reach up to 1800 rpm or more, and domestic also master this core technology, such as Nanjing JlEYA extrusion company, is also currently one of the main choices of domestic high end material processing manufacturers, belongs to the domestic independent innovation national encouragement projects.
If you want to buy twin screw extruders, you can consider our cost effective products. We insist on the tenet of "quality first, customer first" and warmly welcome new and old customers to cooperate with us.
The company focuses on twin screw extruders, micro twin screw extruders, plastic extruders, parallel twin screw extruders, and other research and development and manufacturing as the core of the isotropic rotary twin screw mixing and extruding machine, the application range covers the mixing and modification of granulation, polymerization, deswelling, step molding, recycling, and other fields.
The development and application of twin screw extruders are increasingly eye-catching. Many aspects of the performance of single and twin screw extruders that dominate the extrusion industry can no longer meet the requirements of blending, filling, reinforcement, toughening and other modifications.
What is the structure of the twin screw extruder?
How does the twin screw extruder prevent material degradation?
What are the structural characteristics of the twin screw extruder?
The twin screw extruder, a unique modular screw block is designed on the screw shaft, which is broken three times within a pitch, called a mixing screw block. Corresponding to these gaps, there are three rows of mixing blocks arranged on the inner sleeve of the barrel. The pin and the screw reciprocate in the axial direction at the same time in the process of radial rotation. The twin screw extruder moves in the axial direction once every time it rotates. Due to this special movement mode and the effect of mixing and sorting screws and pins, the material is not only sheared between the mixing pins and the irregular trapezoidal mixing blocks. And it is transported back and forth. The countercurrent movement of the material adds a very useful axial mixing movement to the radial mixing. The melt is continuously cut, turned, kneaded and stretched, and the twin screw extruder regularly interrupts the simple Layered shear mixing.
Due to the simultaneous mixing in the radial and axial directions of the twin screw extruder, the mixing effect is enhanced and the best dispersion mixing and distributed mixing are ensured, so the homogenization time is short. In addition, the mutual engagement of the mixing pin and the screw block also improves the self-cleaning ability of the barrel. The twin screw extruder can ensure stable working pressure through proper screw block combination, without uncontrollable pressure and temperature fluctuations, and prevent material degradation in the barrel.
1. The main machine barrel and screw are assembled by building blocks
The barrel of the twin screw extruder is composed of multiple sets of open and closed barrels. The split barrel can be opened quickly and conveniently for easy cleaning and maintenance; the screw is composed of various mixing sleeves on the mandrel Composed of screw block and conveying screw block. The barrel and screw can be flexibly formed into an ideal form according to different types of materials and different technological requirements.
2. Unique design of gear box and swing box
The twin screw extruder realizes the axial reciprocating movement of the screw while rotating. Every time the screw rotates, it reciprocates once, and the thread is interrupted three times, thus producing a strong mixing effect. The mixing effect is in the axial direction rather than the radial direction, and occurs between the thread and the pin. All materials in the screw channel are subjected to uniform shear stress, instead of a thin layer of material being sheared.
Great products begin with the best engineering staff, and Nanjing JlEYA is ready to assist you with your technical requirements for twin screw extruder.
The twin screw extruder has the basic principles of single-screw extruder: solid conveying, melt pressurization and pumping, mixing and stripping and evaporation, but it is not limited to this. The development of twin screw extrusion theory is relatively late, coupled with its wide variety, messy screw shape, and messy extrusion process, which brings many difficulties to the research. And the following words will give you a brief introduction about the information of the twin screw extruder.
What is the future research direction of twin screw extruder?
What is the basic principle of a twin screw extruder?
What is the difference between a twin screw extruder and a traditional extruder?
1. Established the physical model and mathematical model of the twin screw extruder to guide the design of the twin screw extruder and the optimization of the extrusion process.
2. It is necessary to understand the relationship between the true state change, the mixing form, the whole process of the structure change and the later mixing and characteristics of two or more polymers and materials during the entire extrusion process.
3. As a twin screw extruder, it establishes the internal connection between the entire reaction process, speed and characteristics of the extrusion reaction molding and the screw structure and operating conditions. It can be extruded through reaction molding.
The twin screw extruder has the basic principles of single-screw extruder: solid conveying, melt pressurization and pumping, mixing and stripping and evaporation, but it is not limited to this. The development of twin screw extrusion theory is relatively late, coupled with its wide variety, messy screw shape, and messy extrusion process, which brings many difficulties to the research.
Generally speaking, the research of twin-screw extrusion theory is still in the development link, which is called "technology more than science". From the perspective of the entire extrusion process of a twin screw extruder, there are about three parts: the polymer's physical state change rule during the extrusion process, the basic principle of conveying, the conveying of solid melt, the exhaust phase and the law, and the establishment of mathematics The physical model is used to guide the planning of the twin screw extruder and the optimization of the extrusion system process.
The traditional extrusion molding process requires rotating a giant screw in the barrel. When using twin screw extrusion, the two screws mesh with each other and rotate together during the extrusion operation. They are installed in the housing on the spline shaft of the barrel. The twin screw extruder can simultaneously ensure food molding, heating, cooling, compression, mixing, pumping and even transportation.
At present, twin screw extruder has become the most common extruder with the largest variety and specifications in the world. Nanjing JlEYA has committed to fulfilling all the requirements of twin screw extruders. And it welcomes global customers to purchase.
PVC compounding extruder is divided into RPVC pipe and SPVC pipe, RPVC pipe is easy to cut, welding, bonding, heating can be bent and therefore very easy to install and use. SPVC pipe has excellent chemical stability excellent electrical insulation and good flexibility and colorability this pipe is often used to replace rubber pipe to transport liquid and corrosive media also used as cable casing and wire insulation pipe, etc. So how do choose raw materials and the operation of PVC compounding extruder? The following is a detailed introduction
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Raw material selection
Safety operating procedures
PVC compounding extruder in the production of hard pipe resin should be selected from the lower polymerization degree of SG-5 resin polymerization degree of the higher its physical and mechanical properties and heat resistance is better, but the resin liquidity is poor to bring some difficulties in processing, so generally choose viscosity of 1.7 ~ 1.8 × 10-3Pa-s SG-5 resin is appropriate. Hard pipe generally uses lead-based stabilizers whose thermal stability is good commonly used trisodium lead but its lubricity is poor usually and good lubricity of lead, barium soap type and use. Processing hard tube lubricant selection and use are very important to consider both internal lubrication to reduce intermolecular forces to reduce the viscosity of the melt are conducive to molding and to consider external lubrication to prevent the melt and hot metal adhesion to make the product surface shiny. Internal lubrication is generally used metal soap type external lubrication with low melting point wax. Filler mainly with calcium carbonate and barium barite powder calcium carbonate to make the pipe surface performance of good barium can improve the molding of the pipe easy to shape both can reduce costs but the amount of too much will affect the performance of the pipe pressure pipe and corrosion-resistant pipe is best not to add or add less filler.
1. Personnel without induction test and operation training cannot operate the extruder independently.
2. People who have poor eyesight and slow response can not be on duty to operate.
3. Before starting the machine to do a good job of environmental health around the PVC compounding extruder equipment, equipment around the pile of items not related to production.
4. Check the safety settings of the extruder before production for damage and test whether it can work effectively. Check whether the connection bolts are loose and whether the safety guards are firm.
5. Check the lubrication parts, remove the dirt, and refill the lubricant.
6. PVC compounding extruder barrel and die heating constant temperature time to ensure that the material temperature does not reach the process requirements when driving production.
7. Before starting the screw drive motor to use the hand plate support V pulley, should be flexible rotation, no blocking phenomenon; then start the lubricating oil pump work 3min before starting the screw rotation at low speed.
8. Screw airlift time should not exceed 2 ~ 3min.
9. PVC compounding extruder barrel before adding material to check the barrel, hopper, there is no foreign matter; raw materials should be free of metal, sand, and other impurities to Prevent damage to the screw.
10. The screw starts, the transmission parts work sound normal, the main motor current within the allowable rated value, before allowing the barrel to add material, adding material should first be a small amount of evenly added material.
11. When adjusting the die gap or clearing the dirty material, the operator should wear gloves and not face the barrel and die to prevent the molten material from spraying out of the die and scalding the body.
12. Extruder driving operation is not allowed to repair, and no one is allowed to do any work on the equipment at this time.
13. In case of the following phenomena, should be an emergency stop.
Bearing parts of the high temperature, lubricating oil (grease) out; motor odor, smoke, or shell temperature is too high; speed box lubricating oil temperature, smoke; transmission parts emit irregular abnormal sound; machine work produces violent vibration; screw suddenly stop rotating.
14. PVC compounding extruder equipment on the safety cover and the location of the safety alarm device is not allowed to change at will, not to mention artificially caused by the malfunction.
15. Find that the equipment leakage, oil leakage phenomenon should be timely maintenance troubleshooting, no water, oil flow around the machine.
If you have questions about how to use the PVC composite extruder, you can contact us on the official website. We are happy to answer for you.
Nanjing Team sincerely invite you to attend The 15th China Chongqing Rubber, Plastics Industry Exhibition.
Our booth no.: S2544
Time: May 27-30, 2021
Address: Chongqing International Expo Center
Wish to meet you at there ;)
The twin screw extrudernot only has the characteristics of a single-screw extruder, but also has the advantages of convenient feeding, stable extrusion, and convenient exhaust. It is widely used in the production and processing of extruded products.
Why are twin screw extruders warmly welcomed now?
Choose a single-screw extruder or a twin screw extruder?
What are the technical points of the twin screw extruder?
Why are twin screw extruders warmly welcomed now?
The twin screw extruder can not only add more ingredients to the company's products, but also can choose to quickly complete the manufacturing. Considering that "new crown pneumonia" has put every industry into trouble, the market has been looking for a quick turnaround to pay for healthy food. In addition, you may need to make up for the loss of production and sales or increase production and sales based on the current situation. Twin-screw extension can help you, and considering the lower cost and higher production and sales, it can bring more profits.
Choose a single-screw extruder or a twin screw extruder?
The single-screw extruder is used for extrusion processing technology and equipment, and the particle raw materials stay in the extruder for a long time. This means that a single-screw extruder requires a longer period than a twin screw extruder to produce the products required by the enterprise. In addition, the twin screw extruder allows you to better control the complex operation process and actual operation. As everyone knows, these controls are much more complicated. This is very important for foods that need to be mixed and mixed. The production and manufacturing facilities are complete, and the actual effect of twin-screw extrusion is the best. For polymer materials, twin-screw extrusion is also particularly effective. Considering that the design concept of twin screw extruder has a relatively large flexibility, it can be used in many industries for very specific operation processes.
What are the technical points of the twin screw extruder?
In the extrusion process of the twin screw extruder, the material is transformed from the glass state to the molten state. In addition to the balance between the heat required for plasticization of the material and the amount of heat supplied, the material is melted. Pressure is also a very important control indicator. Because the material is affected by the compression ratio of each section of the die resistance screw during the extrusion process, it does not exist under normal pressure. For different die, the compression ratio of each section of the screw is basically constant and immutable. Under the premise of the same extrusion speed, increase or decrease the feed rate, the volume of the screw material in the feeding section will change, and the volume of the material in the exhaust section will remain unchanged, so the compression section of the feeding section changes with the compression ratio, and its melt pressure follows Increase or decrease; under the premise of the same feed rate, increase or decrease the extrusion rate, the volume of the screw material in the feeding section will also change. The volume of the material in the exhaust section remains unchanged, so the compression section of the feed section changes with the compression ratio, and its melt pressure increases or decreases accordingly; the feed speed increases or decreases simultaneously with the extrusion speed, because the volume of the screw material in the feed section remains unchanged , Only due to the increase or decrease of the speed, the melt pressure change.
Due to different fields and different types of twin screw extruder, they are widely used in many industries. To meet these growing demands, Nanjing JlEYA has committed to providing the increasing of twin screw extruder.
The single-screw extruder has a simple design and a low price, so it is widespread and demand on the market was high.
What are the application areas and benefits of single-screw extruders?
What is the development history of the single-screw extruder?
What are the main technical parameters of the single-screw extruder?
The single-screw extruder is mainly used for extruding soft and hard polyvinyl chloride, polyethylene, and other thermoplastic. It can process a variety of plastic products such as films, tubes, plates, tapes, etc., can also be used for granulation.
The single-screw extruder is characterized by advanced design, high quality, good plasticization, and low energy consumption. It uses an evolutionary drive that is characterized by low noise development, stable operation, high load capacity, and long service life.
The single-screw extruder is one of the most important devices for the processing of plastic molding parts. It uses external energy transfer and heat transfer of external heating elements to carry out the transport of plastics solids, compaction, melting, shielding, and extrusion forms.
Since the birth of the snail extruder, it has evolved from an ordinary snail extruder to a new type of snail extruder after almost a hundred years of development. Although there are many types of new single-screw extruders, the extrusion machine is the same.
The extrusion process of the traditional snail extruder is realized by heating outside the cylinder, solid and cylinder, snail friction, and melting shear force.
"friction coefficient" and "friction force", "viscosity" and "shear tension" are the main factors influencing the performance of conventional screw extruders. The extrusion process from the machine is unstable and difficult to control, especially for some heat-sensitive plastics with poor thermal stability and high viscosity.
1. Screw diameter: refers to the diameter of the outer circle of the screw, marked with D, and the unit is millimeter (mm).
2. Proportion of screw length to diameter: refers to the ratio of the length L of the working part of the screw (the length of the threaded part, i.e. the length from the center line of the feed opening to the end of the screw) and the screw diameter D, expressed by L/D.
3. Snail speed range: refers to the highest speed of the snail up to the lowest speed of the snail; n is used to represent the speed of the snail, and the unit is revolutions per minute (U/min).
4. The power of the main screw drive engine: expressed by P, the unit is kilowatt (kW).
5. Heating performance of the extruder cylinder: expressed by E is the unit kilowatt (kV).
6. The output capacity of the extruder: expressed by Q, the unit is kilogram per hour (kg/h).
7. The height of the extruder rim: refers to the distance from the center line of the screw to the ground, expressed by H, and the unit is millimeters (mm).
8. Extruder outer dimensions: refers to total length (x) total width (x) total height expressed by L x B x H, and the unit is millimeters or meters (m m or m)
9. Extruder quality: expressed in W, the unit is kilogram or tonne (kg or t).
We can see the huge role that single-screw extruders play in the production industry, and they have become indispensable components. And Nanjing JlEYA a Chinese pioneer in single-screw extruder production,has committed to providing the most suitable single-screw extruder at a reasonable price, and whatever it takes to satisfy the customer’s needs.