








In terms of the principle of motion, there are different types of twin-screw extruderswith isotropic and anisotropic meshing and non-meshing types. So what are the types of twin-screw extruders? And what are the application areas? The following is a detailed introduction.
Here is the content list:
l Isotropic twin-screw extruder
l Anisotropic twin-screw extruder
l Non-Engaging Twin-Screw Extruders
l SHJ-20 twin-screw laboratory extruder
l Application areas
These extruders are available at low and high speeds, the former mainly for profile extrusion, while the latter is used for special polymer processing operations.
(1) Close-meshing extruder. Low-speed extruders have a closely meshed screw geometry, where the profile of one screw is closely matched to the profile of the other screw, i.e., a conjugate screw profile.
(2) Self-cleaning extruder. High-speed co-rotating extruders have a closely matched screw-prong profile. This screw can be designed to have a fairly small screw gap so that the screw has a closed self-cleaning effect, this twin-screw extruder is called a tight self-cleaning co-rotating twin-screw extruder.
The tightly meshed anisotropic twin-screw extruder has a small gap between the two screw grooves (much smaller than that in a co-engaged twin-screw extruder) so that a positive conveying characteristic can be achieved.
The center distance between the two screws of a non-engaging twin-screw extruder is greater than the sum of the radii of the two screws.
It is suitable for universities, colleges, and scientific research laboratories for process and formula development, etc. It has the features of beautiful appearance, compact structure, easy to use and maintain, and precise control of process conditions. Gearbox homemade torque level: T/A3≤8 national standard main parts, twin-screw extruder new structure design, and hardened gear teeth of high precision grinding, to ensure that the gearbox works efficiently for a long time. Screw self-made: Screw elements with tightly meshed design, block type, can be easily replaced to suit different materials. Barrel captive: The precision grade of the twin-screw extruder can reach T6, favorable to energy saving, and the block type design makes various combinations possible.
The two main areas of application of twin-screw extruders are extrusion of thermosensitive materials such as PVC pipes and profiles and processing of special polymers such as blending, venting, chemical reactions, etc. Twin-screw extruders for profile extrusion have intermeshing screw ribs and grooves and operate at a low speed of about 10/min or less. Compared to single screws, twin-screw extruders have much better feeding and conveying performance, especially for those difficult to feed and easy to slip, such as fibrous, powdery, and greasy materials. The short and uniform material retention time, better mixing, and larger heat transfer area allow for good material temperature control, which is especially important for processing heat-sensitive materials.
If you want to buy a twin-screw extruder, you can consider our cost-effective products.
Nanjing JlEYA is the leading manufacturer extruder manufacturer specializing in a twin-screw extruder, mini twin screw extruder, plastic extruder, and parallel twin-screw extruder in China, which is widely used in compounding, modification, polymerization, devolatilization, reaction, recycling, After 17 years of development, now we have 20,000 square meters workshop with annual sales over 300+ sets, export over 60 countries.
Nanjing JIEYA hereby sincerely invited you to attend 2021 China (Hainan) Degradation Exhibition.
Our booth no.: B06
Time: June 23-25
Add: Hainan International Convention and Exhibition Center
We warmly welcome your coming and look forward to cooperate with you ;)
The basic mechanism of the twin screw extrusion process is simply that a screw rotates in the barrel and pushes the plastic forward. The screw structure is a bevel or ramp wrapped around a central layer, the purpose of which is to increase the pressure to overcome the higher resistance. What do I need to pay attention to when using a twin screw extruder? The following is a detailed description.
Here is the content list:
l Structural principles
l Temperature principles
l Speed reduction principle
For the extruder, there are three kinds of resistance to overcome when working: one is friction, which contains the friction of the solid particles (feed) on the barrel wall and the mutual friction between them during the first few turns of the screw (feed area); the second is the adhesion of the melt on the barrel wall, and the third is the resistance of the internal logistics of the melt when it is pushed forward.
According to Newton's theorem, if an object is at rest in a certain direction, then the object is in a state of equilibrium balance of forces in this direction. For the circumferential movement of the screw, it is no axial motion, that is, the axial force on the screw is in equilibrium. So if the screw exerts a large forward thrust on the plastic melt, it also exerts a backward thrust on another object of the same magnitude but in the same direction. The thrust is exerted on the thrust bearing behind the feed opening. Most single screws have right hand threads, and if viewed from the back, they rotate backward, and they spin backward out of the barrel by rotational motion. In some twin screw extruders, however, the two screws rotate backward and cross each other in both barrels, so one must be right handed and one left handed, and in the case of an occluding twin screw, both screws rotate in the same direction and must therefore have the same orientation. However, in either case, there are thrust bearings that withstand backward forces and still comply with Newton's theorem.
Plastics extruded by twin screw extruders are thermoplastics, which melt when heated and solidify again when cooled. Thus, heat is needed during the extrusion process to ensure that the plastic can reach the melting temperature. So where does the heat to melt the plastic come from? First of all, the pound feed preheat and barrel/die heaters may play a role and are very important at startup. In addition, the motor feed energy, the frictional heat generated in the barrel as the motor overcomes the resistance of the viscous melt and turns the screw, is the most important heat source for all plastics, except for small systems, low speed screws, high melt temperature plastics, and extrusion coating applications. In operation, it is important to recognize that the barrel heater is not the primary heat source and that it may play a smaller role in extrusion than we might expect. The post barrel temperature is more important because it affects the rate of solids transport in the dentition or feed. In general, except for a specific purpose (such as varnishing, fluid distribution, or pressure control), the die head and die temperature should be at or near the temperature required for the melt.
In most twin screw extruders, the screw speed is varied by adjusting the motor speed. The drive motor usually turns at a full speed of about 1750 rpm, which is too fast for an extruder screw. If it turns at such a fast speed, too much frictional heat is generated and a uniform, the well mixed melt cannot be prepared because the retention time of the plastic is too short. A typical speed reduction ratio should be between 10:1 and 20:1, with either a gear or pulley set for the first stage, but with a gear and a screw positioned in the center of the last large gear for the second stage. For some slow running machines (eg. twin screws for UPVC), there may be three reduction stages and the maximum speed may be as low as 30 rpm or less (ratio up to 60:1). On the other hand, some very long twin screws for mixing can run at 600 rpm or faster, thus requiring a very low reduction rate and more deep cooling. If the reduction rate is incorrectly matched to the job, too much energy will be wasted. It may be necessary to add a pulley set between the motor and the first deceleration stage where the maximum speed is changed, which either increases the screw speed even beyond the previous limit or reduces the maximum speed. This increases the available energy, reduces the current value, and avoids motor failure, in both cases, the output may increase due to the material and its cooling needs.
If you still have questions, you can consult our company. Nanjing JlEYA is the leading professional manufacturer of twin screw extruders in China.
Nanjing JIEYA attend Chinaplas 2021 held in Shenzhen. We sincerely welcome your visiting.
Our booth no.: 7Q25
Time: April 13-16, 2021
Address: Shenzhen World Exhibition Center
Look forward to meet you at there.
![]() | ![]() |
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:
Daily maintenance.
Regular maintenance.
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.
The high efficiency of the single-screw extruderis mainly reflected in high output, low energy consumption, and low manufacturing cost. In terms of function, the plastic extruder has been used not only for extrusion molding and mixing processing of polymer materials but its use has been broadened to food, feed, electrode, building materials, packaging, ceramics, and other fields. So how to operate the single screw extruder? The following is a detailed introduction.
Here is the content list:
Preparation work before starting the machine
Start-up operation
Stop operation
1. For single-screw extruder extrusion production of materials, should meet the required drying requirements, if necessary, further drying.
2. According to the variety of products, size, select the head specifications, the machine will be installed in the order of the column, installed head flange, die body, mouth die, porous plate, and filter network.
3. Connect the compressed air pipe, install the core mold electric heating rod head heating ring, check the water system.
4. Adjust the gap evenly in all parts of the mouth die and check whether the centerline of the main machine and the auxiliary machine are aligned.
5. Start the single-screw extruder of each running equipment, check whether the operation is normal, and find faults in time to eliminate.
6. Turn on the electric heater, the head, body, and auxiliary machine evenly heated up, to be the temperature of each part than the normal production temperature of about 10 degrees, constant temperature of 30 ~ 60 minutes so that the machine temperature inside and outside the same.
Start-up is an important part of the production, poor control will damage the screw and head, the temperature is too high will cause plastic decomposition, the temperature is too low will damage the screw, barrel, and head. The start-up steps are as follows.
1. Start the machine at low speed, idle, check the screw for any abnormalities and motor, amperage meter current no overload phenomenon, the pressure gauge is normal. Machine idling should not be too long to prevent the screw and barrel-scraping grinding.
2. Gradually add a small amount of material, wait for the material extrusion out of the die, before the normal addition of material. Before the plastic is extruded, no one should be in front of the mouth die to prevent casualties.
3. After the plastic is extruded, it is necessary to lead the extruded material slowly on the cooling and shaping, traction equipment, and start this equipment beforehand. Then, according to the control instrument indication value and the requirements of the extruded products, each link will be properly adjusted until the extrusion operation reaches the normal state.
4. Cutting and sampling, checking whether the appearance meets the requirements, whether the size meets the standard, quickly testing the performance, and then adjusting the extrusion process according to the requirements of quality, so that the products meet the standard requirements.
1. Stop feeding, extrude the plastic in the single screw extruder and turn off the power of the barrel and head for the next operation.
2. Shut off the power of the main machine and the auxiliary machines at the same time.
3. Open the head connection flange, clean the porous plate and various parts of the head, when cleaning, should use copper rods, copper pieces, after cleaning, apply a little oil. Screw, barrel clean up, if necessary, the screw from the end of the machine out of the top, clean up after recovery, in general, available for the transition of material cleanup.
4. Extrusion of polyolefin plastics, usually in the extruder full load shutdown (with material shutdown), when the air should be prevented from entering the barrel, so as not to oxidize the material and affect the quality of the product when continuing production. For polyvinyl chloride plastics, can also stop with material, then close the material door, reduce the temperature at the head connection body (flange) 10 ~ 20 degrees, to stop the machine after the material squeeze net.
5. Close the total power and cooling water main valve.
If you still have questions, you can consult our company. Our company's website is https://www.njjyextrusion.com/
With the development of modern industry, the underwater pelletizing machine has become an important production equipment used in all aspects of production.
What is the working principle of the underwater pelletizing machine?
What is the operating procedure of the underwater pelletizing machine?
What are the reasons why people choose underwater pelletizing machine?
The material using the underwater pelletizing machine will pass through the feeding port, and under the action of the rotating screw, it will be rolled into a dough and roll forward along the screw groove. Due to the shear, compression and agitation of the screw, the material will be further mixed and plasticized. , The temperature and pressure gradually increase, showing a state of viscous flow, and passing through the machine head with a certain pressure and temperature, and finally a product of the desired shape is obtained.
(1) Check the rotation direction of the impeller of the underwater pelletizing machine. From the feed inlet, the impeller should turn counterclockwise, otherwise the motor connection should be adjusted.
(2) The starting sequence of the underwater pelletizing machine and the material conveying equipment is as follows:
Discharge belt conveyor→PL vertical impact crusher→feeding belt conveyor
The crusher must be started without load, and the material can only be fed after the crusher is running normally.
(3) The feed size is strictly in accordance with the feed size specified by the various models. It is forbidden to enter the underwater pelletizing machine with the size of the material larger than the specified size, otherwise it will cause the impeller imbalance and excessive wear of the impeller, and even block the impeller flow path and The central feed pipe prevents the crusher from working normally. When a large piece of material is found, it should be removed in time.
(4) When the discharge belt conveyor stops running, the feeding should be stopped immediately, so the discharge belt conveyor should be interlocked with the feeding system to open and stop. Otherwise, the impeller will be crushed and the motor will be burnt.
(5) The feeding of the underwater pelletizing machine should be uniform and continuous.
(6) During the operation of the underwater pelletizing machine, there must be no violent vibration or abnormal noise, otherwise, it should be stopped immediately for inspection, and the machine can only be driven in order after the fault is removed.
(7) The observation door should be sealed tightly during the working process of the underwater pelletizing machine.
The difference between the underwater pelletizing machine and other similar products is that it has a steady stream of water flowing through the mold surface, and it is in direct contact with the mold surface. The size of the pelletizing chamber is just enough to allow the pelletizing knife to rotate freely across the die surface without restricting the temperature of the water flow. The molten polymer has been extruded from the die, and the rotating knife cuts the pellets. And then the pellets are taken out of the pelletizing chamber by the temperature-regulated water and enter the centrifugal dryer. In the dryer of the underwater pelletizing machine, the water will be drained back to the storage tank, cooled and recycled; the pellets pass through the centrifugal dryer to remove the water.
This is how we see the irreplaceable role of underwater pelletizing machine in our daily lives and industrial production. Nanjing JlEYA, the pioneer of underwater pelletizing machine producing company in China, knows that every application is special. You can go and get more information about them
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.