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.
As common extruder equipment used in the plastic processing industry, single screw extruder is mainly used for extruding soft and hard PVC, polyethylene, and other thermoplastics, which can process many kinds of plastic products, such as blown film, extruded pipe, pressboard, drawn ribbon, etc. It can also be used for melt pelletizing. The plastic extruder has advanced design, high quality, good plasticization, low energy consumption, involute gear transmission, low noise, smooth operation, high load capacity, and long life. To have a long service life of the machine, maintenance measures are indispensable, the following is a detailed description of the single-screw extruder maintenance measures.
Here is the content list:
1. Because the electrical control system of single-screw extruder has high requirements for ambient temperature and dustproof, the electrical system should be separated from the production site, and install ventilation or ventilation fan, it is recommended that the electrical control cabinet in a simple room, keep the room clean, ventilation, so that the indoor temperature is not higher than 40 ℃.
2. Single-screw extruderis not allowed to run empty, so as not to roll the screw and machine simple hair. Host start idling is not allowed to exceed 100r / min; start the host first low speed, after starting the host to check for abnormal noises and then slowly increase the host speed to within the allowable range of the process (can be adjusted to the best state is good). When the new machine is breaking in, the current load should be at 60-70%, and the current in normal use should preferably not exceed 90%. Note: If an abnormal sound occurs when the extruder is running, it should be stopped immediately for inspection or repair.
3. Turn on the oil pump first and turn off the oil pump after shutting down the machine; keep the water pump working during the whole production process and do not stop the pump to avoid the barrel temperature rising and causing the material in the barrel to decompose and carbonize; the asbestos wind cover of the main motor fan needs to be cleaned often to avoid the dust sticking too much to block the wind cover and cause the motor to overheat and trip due to insufficient heat dissipation.
4. Clean up the dust and dirt, tools, and debris on the surface of the unit in time.
1.Regularly check the screws and other fasteners on the surface of the single-screw extruder unit for looseness and timely and proper tightening. The lubricant level of the transmission box should be added or replaced promptly (the dirt at the bottom of the oil tank should be cleaned regularly). For new machines generally, 3 months to replace the oil, after that every six months to a year. The oil filter and oil suction pipe should be cleaned regularly (once a month).
2. Single screw extruder gearbox maintenance and general standard reducer are the same. The main thing is to check the wear and failure of gears and bearings.
3, When reinstallation please note that A, B two screws must be in the original position, can not be replaced! After the installation of the new combination of the screw on the machine, you must first use the hand pan car, such as normal rotation before the low-speed start. Screw or barrel for a long time without use, there should be anti-rust and anti-fouling measures, the screw should be placed hanging. If the threaded block is with fire, the flame should be moved left and right, while burning to clean up, and can not burn too much (blue ringers red), not to mention the thread block into the water.
4. Regularly calibrate the temperature control instrument to check the correctness of its adjustment and the sensitivity of its control.
5. In the barrel with a cooling water tank, must be used distilled water to prevent the formation of scale blocking the cooling water channel in the barrel, resulting in temperature failure. Pay attention to the appropriate amount of water in use to prevent scaling. If the blockage should be changed down the cylinder specific maintenance, no blockage and the water output is small indicates that there is scale, the tank water should be changed to dilute hydrochloric acid swishing cycle, clear scale to normal and then change the distilled water. General water in the tank is used to cool the barrel, and the natural water we pass is used to cool the tank. Regularly check the water quality of the cooling water tank, if there is turbidity, should be replaced promptly.
6.Check whether the solenoid valve is working properly, the coil has not burned out if there is a timely replacement.
7. The temperature does not rise to quite the temperature continues to rise and fall may exist for the following reasons: whether the day electric couples loose fall; heater relay is working properly; solenoid valve is working properly, timely replacement of deformation of the heater, and tighten the screws.
8. Timely clean up the dirt in the vacuum tank, and the material in the exhaust chamber so that the pipeline is smooth. Vacuum pump seals need to be replaced promptly if there is wear and tear regular inspection, the output shaft jumping is bearing damage and shaft fracture must be opened and replaced, such as the gearbox two output shaft bearing position wear is too serious, the box must be replaced to avoid greater loss of failure.
9, To drive the screw rotation of the DC motor to focus on checking the brush wear and contact, the insulation resistance value of the motor whether in the specified value should also be measured frequently. In addition, check the connection line and other components that are rusted, and the use of protective measures.
10. When the single-screw extruder needs to stop using for a long time, should be in the screw, Jane, the head, and other working surfaces coated with anti-rust grease. The small screw should be suspended in the air or placed in a special wooden box, and a wooden block pad flat, so as not to deform the screw or bruise.
11. Single-screw extruder attached to the cooling water pipe wall is prone to scale external corrosion and rust. Maintenance should be carefully checked, too much scale will block the pipeline, can not achieve the cooling effect, rust will be serious leaks, so maintenance must take descaling and anti-corrosion cooling measures.
12. Designate a person responsible for the maintenance of equipment. And each maintenance and repair detailed record is included in the plant equipment management files.
If you still have questions, you can consult our company, we are happy to answer for you. The company insists on the purpose of "quality first, customer first", and warmly welcomes new and old customers to cooperate with us.
Nanjing Jieya is a professional manufacturer of twin screw compounding extruders since 2004. Our extruders series include SHJ series, HT series, JY series, SJ series, etc. Today we will tell you the differences between SHJ series twin screw extruders and HT series high torque twin screw extruders from three main points below:
1. Torque grade
The torque rating grade of our SHJ series twin screw extruder is T/A3≤8 while HT series is 9≤T/A3≤13.5. Our HT series adopt high torque gear box, which is suitable for customers that pursuit high efficiency machines.
2. Power transmission
SHJ series use clutch for power transmission while HT series use torque protector, for example, R+W brand, Bibby brand, etc.
The output of HT series twin screw extruder is much higher than SHJ series.
So HT series can further improve the performance of extruders.But surely, price is higher than SHJ series.
The main system of the plastic extruder is the extrusion system, which includes screw, barrel, hopper, head, and die. The plastic is plasticized into a uniform melt by the extrusion system and is continuously extruded from the head by the screw under the pressure established in the process. The following are details about the plastic extruder extrusion system introduction.
Here is the content list:
Head and mold.
The screw is the most important part of the extruder, which is directly related to the application range and productivity of the extruder and is made of high-strength and corrosion-resistant alloy steel.
The barrel is a metal cylinder, generally made of heat-resistant, high-pressure strength, strong wear-resistant, corrosion-resistant alloy steel or composite steel tube lined with alloy steel. The barrel and the screw cooperate to realize the crushing, softening, melting, plasticizing, exhausting, and compacting of the plastic, and to continuously and evenly deliver the rubber to the molding system. Generally, the length of the barrel is 15-30 times its diameter, so that the plastic is fully heated and fully plasticized as a principle.
The bottom of the hopper is equipped with a cut-off device to adjust and cut off the material flow, and the side of the hopper is equipped with a sight hole and a calibrated measuring device.
The head is composed of alloy steel inner sleeve and carbon steel outer sleeve, the head is equipped with a molding mold, the role of the head is to transform the rotational movement of the plastic melt into a parallel linear motion, evenly and smoothly into the mold sleeve, and give the plastic to the necessary molding pressure. The plastic is plasticized and compacted in the barrel and flows through the neck of the head through a certain flow path through the porous filter plate into the forming mold of the head. The mold core and mold sleeve are properly matched to form an annular gap with decreasing cross-section so that the plastic melt forms a continuous dense tubular cladding layer around the core line. To ensure that the plastic flow channel in the head is reasonable and to eliminate the dead angle of the accumulated plastic, there is often a diversion sleeve placed, and to eliminate the pressure fluctuation of plastic extrusion, there is also a pressure equalization ring set. The head is also equipped with a die correction and adjustment device to facilitate the adjustment and correction of the concentricity of the die core and die sleeve.
The extruder head is divided into an angled head (120o angle) and a right angle head according to the angle between the head material flow direction and the screw centerline. The shell of the head is fixed to the body with bolts, the die inside the head has a die core sitting and is fixed to the head inlet port with a nut, the front of the die core seat is equipped with a die core, the die core and the center of the die core seat has a hole for passing the core line, the front of the head is equipped with an even pressure ring for equalizing the pressure, the extrusion package forming part is composed of die sleeve seat and die sleeve, the position of the die sleeve can be adjusted by bolts through the support to adjust the die sleeve to the die core The position of the die sleeve can be adjusted by bolts through support to adjust the relative position of the die sleeve to the die core, which is convenient to adjust the uniformity of the thickness of the extruded layer.
If you want to buy a plastic extruder or want to know more, you can visit our official website. Our website is https://www.njjyextrusion.com/
A single-screw extruder consists of an Archimedes screw rotating in a heated barrel. It is widely used because of its simple structure, easy manufacturing, high processing efficiency, and low price, and is the most technically mature and used type of extruder at present. The following is a detailed introduction to single-screw extruders.
Here is the content list:
The design concept of a single-screw extruder
Single-screw extruder features
Uses of single screw extruder
(1) Single-screw extruders are high-speed, high-output extrusions based on high quality, and the design concept of low-temperature plasticization ensures the extrusion of high-quality products. Two-step overall design to strengthen the plasticizing function and ensure the adjustment of high-performance extrusion.
(2) A special barrier of the single-screw extruder, integrated mixing design to ensure material mixing effect and high torque output, extra-large thrust bearing.
(3) The gears and shafts of a single screw extruder are high-strength alloy steel, carburized, ground teeth treatment, high hardness, high finish, and ultra-low noise. PLC intelligent control, the linkage between main and auxiliary machines is possible.
(4) Single screw extruder easy to monitor human-machine interface, easy to understand the processing and machine status, and the control method (temperature control instrument) can be changed as needed.
(5) The material of the single screw extruder is 38CrMoAL/A nitride treatment, which is wear-resistant. It has a combination of air-cooled and water-cooled cooling for strict temperature precision control, and the unique air inlet design makes it a perfect water-cooling device.
(6）Single screw extruder with grooved surface feeding bottom sleeve of screw barrel has enhanced feeding function, which provides a guarantee for high speed and high output extrusion.
1. Hard gearbox, AC or DC stepless drive speed regulation.
2. New screw structure, melt and mix uniformly to ensure low melt temperature and high output
3. Screw barrel material adopts nitride steel 38CrMoAIA nitride treatment, and the surface alloy treatment has higher hardness.
4. Cast copper, cast aluminum heater, air-cooled and water-cooled according to requirements.
5. Advanced electrical control system of single screw
Pipe extrusion of single-screw extruder: it is suitable for PP-R pipe, PE gas pipe, PEX cross-linked pipe, aluminum-plastic composite pipe, ABS pipe, PVC pipe, HDPE silicon core pipe, and various co-extruded composite pipes.
Sheet and plate extrusion: applicable to PVC, PET, PS, PP, PC, and other profiles and plates extrusion. Extrusion of various other plastics such as silk, rod, etc.
Profile extrusion: adjusting the extruder speed and changing the structure of the extrusion screw can be applied to the production of various plastic profiles such as PVC, polyolefin, etc. Modified pelletizing: It is suitable for blending, modifying, and enhancing pelletizing of various plastics.
Nanjing JlEYA is a leading extruder manufacturer specializing in a twin-screw extruder, micro twin-screw extruder, plastic extruder, and parallel twin-screw extruder, which are widely used in compounding, modification, polymerization, devolatilization, reaction, recycling, and other fields. After 17 years of development for many years, now we have a 20,000 square meters plant, 300+ sets of annual sales, and export to more than 60 countries.
The screw can be said to be the heart of the injection molding machine. The quality of the screw determines the quality of the product. The plasticizing screw of the engineering plastic twin screw extruder has the functions of conveying, melting, mixing, compression, metering and exhausting. It plays an important role in the quality of plasticization and is a key factor affecting the quality of plasticization.
What is the difference between engineering plastic twin screw extruder and single screw extruder?
What are the characteristics of engineering plastic twin screw extruder?
What are the structural principles of engineering plastic twin screw extruder?
1. Price: single screw extruder has simple structure and low price; Engineering plastic twin screen expander is complex and expensive
2. Plasticizing capacity: single screw extruder is suitable for plasticizing and extruding polymers and granular materials. The shear degradation of polymer is small, but the residence time of material in extruder is long; The engineering plastic twin screw extruder has good mixing and plasticizing ability, and the residence time of materials in the extruder is short, which is suitable for powder processing.
3. In terms of processing capacity and energy consumption: the engineering plastic twin screw extruder has large output, fast extrusion speed and low energy consumption per unit output, while the single screw extruder is poor.
4. Operability: the single screw extruder is easy to operate and the process control is simple; The operation of engineering plastic twin screen expander is relatively complex and the process control requirements are high.
1. engineering plastic twin screw extruder is divided into parallel and conical according to the relative position of the two axes;
2. engineering plastic twin screw extruder is divided into meshing type and non-meshing type according to the two screw meshing procedures;
3. engineering plastic twin screw extruder is divided into the same direction and the opposite direction according to the rotation direction of the two screws, and there are inward and outward points in the opposite direction;
4. engineering plastic twin screw extruder is divided into high speed and low speed according to the screw rotation speed;
5. engineering plastic twin screw extruder is divided into whole and combination according to the structure of screw and barrel.
For the basic mechanism of the engineering plastic twin screw extruder process, in simple terms, a screw rotates in the barrel and pushes the plastic forward. The screw structure is an inclined surface or slope wound on the center layer, the purpose of which is to increase the pressure in order to overcome the greater resistance. As far as the engineering plastic twin screw extruder is concerned, there are three kinds of resistance that need to be overcome during work: one is friction, which includes the friction of solid particles (feeding) against the barrel wall and the first few revolutions of the screw (feeding zone). There are two kinds of mutual friction forces; the second is the adhesion of the melt on the cylinder wall; the third is the internal logistics resistance of the melt when it is pushed forward.
Nanjing JlEYA has focused on the development and production of engineering plastic twin screw extruders for several years. And it commits to provide perfect service for every customer from all over the world.
underwater pelletizing machine is similar to airflow granulator and water jet granulator. The equipment part mainly covers: plastic granulator, single and twin screw plastic extruder, plastic film blowing machine, bag making machine, printing machine, coating machine, Adhesive tape machine, tape slitting machine, slitting machine, strapping machine.
What is the problem of uneven pelletizing by the underwater pelletizing machine?
What is the workflow of the underwater pelletizing machine?
What is the technological advantages of the underwater pelletizing machine?
1. underwater pelletizing machine, the machine head is not evenly heated, and the machine head temperature is stable before starting up;
2. The cooling water of the underwater pelletizing machine is boiled prematurely, and the water should be boiled when the machine head starts to discharge;
3. It is also possible that there is a problem with the hot runner design of the machine head, which is caused by uneven pressure.
Before being made into final products, most polymers must be blended and then pelletized to become marketable raw materials. The power required by the underwater pelletizing machine is directly proportional to the extrusion volume and exponentially related to the size of the filter screen. There are many different types of pelletizer designs, but all pelletizers have some common places, and they can be divided into two categories: cold pelletizing system and die face hot pelletizing system. The main difference between the two categories is the time arrangement of the pelletizing process. The cold pelletizing system cuts pellets from the solidified polymer at the end of the process; while in the die-face hot pelletizing system, pellets are cut when the molten polymer emerges from the die, and pellets are processed downstream cool down.
The underwater pelletizing machine treated by standard process has the following significant advantages:
The appearance standard of the products produced by the underwater pelletizing machine is exquisite and bright;
2. The hardness of the wear layer in contact with the material by the underwater pelletizing machine can reach HV 600-800, and the local hardness can reach HV900-1100. The hardness is increased to 2-4 times the original hardness. Compared with the non-standard machine without heat treatment, it is resistant to The wear performance is increased by 3-5 times;
3. The products of the underwater pelletizing machine are not deformed after long-term use, effectively avoiding the screw breaking due to the excessive wear of the barrel, and the stable service life is 2-3 times that of the traditional machine, which greatly reduces the investor's investment in replacement parts;
4. The wear-resistant layer of the barrel screw produced by the underwater pelletizing machine has high hardness, while the base material still retains good toughness and processing performance;
5. The service life of the screw of the underwater pelletizing machine has increased from the hundred-ton level of the ordinary plastic pelletizing machine to the thousand-ton level.
Nanjing JlEYA has focused on the production and development of underwater pelletizing machines for several years, and they have always put the needs of customers as their top priority. Here, you can choose the underwater pelletizing machine that suits your need.
The difference between single screw extruder and twin screw extruder: one is a screw, the other is two screws. Both are driven by a motor. The power varies with different screw sizes. The power of 50 conical twin screw extruder is about 20kW, and 65 is about 37kW. The output is related to the material and the screw size. The output of 50 conical twin screw extruder is about 100-150kg/h, and 65 conical twin screw extruder is about 200-280kg/h. The output of a single screw is only half than twin screw extruder.
Extruders can be divided into single-screw, twin-screw and multi-screw extruders according to the number of screws. Today, the single-screw extruder is the most widely used and is suitable for extrusion processing of general materials. The twin-screw extruder has the characteristics of less heat generated by friction, relatively uniform shearing of the material, large conveying capacity of the screw, relatively stable extrusion volume, long residence of the material in the barrel, and uniform mixing.
The single-screw extruder occupies an important position both as a plasticizing and granulating machine or a molding and processing machine. In recent years, the single-screw extruder has made great progress. The large-scale single-screw extruder for granulation produced in Germany has a screw diameter of 700mm and an output of 36t/h.
The main sign of the development of single-screw extruder lies in the development of its key part, the screw. In recent years, people have carried out a lot of theoretical and experimental research on screws. There are nearly 100 types of screws. The common ones are separation type, shear type, barrier type, split type and wave type.
From the perspective of single-screw development, although the single-screw extruder has been relatively complete, with the continuous development of polymer materials and plastic products, new and special single-screw extruders with more characteristics will emerge. In general, single-screw extruders are developing in the direction of high speed, high efficiency and specialization.
The twin-screw extruder has good feeding characteristics, is suitable for powder processing, and has better mixing, exhaust, reaction and self-cleaning functions than single-screw extruders, and is characterized by processing plastics and blends with poor thermal stability. It shows its superiority even more.