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.
Each type of product in the plastic extruder line has its operating characteristics, and a detailed understanding of its operating characteristics is necessary to give full play to the effectiveness of the machine. The following is a detailed description of the operating procedures and maintenance methods for plastic extruders.
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The plastic extruder is one of the machine types, master the extruder operation points, the correct and reasonable use of a plastic extruder. The use of plastic screw extruder includes a series of links such as installation, adjustment, commissioning, operation, maintenance, and repair of the machine, and its use has the commonality of general machines, mainly in the drive motor and reduction and speed change device. However, the working system of the plastic screw extruder, the extrusion system, is unique, and special attention should be paid to its characteristics when using the plastic screw extruder. Extruder manuals generally have clear provisions for the installation, adjustment, and commissioning of the machine, here the main points of the operation, maintenance, and repair of the plastic screw extruder are briefly described as follows: in particular, to correctly grasp the structural characteristics of the screw, heating and cooling management instrumentation characteristics and assembly, the correct extrusion process conditions, the correct operation of the machine.
1.Pastic extruder equipment should be placed in a ventilated position to ensure that the heat of the motor work prolongs its life; the machine should be kept well grounded.
⒉Regularly check the tool screws, the plastic extruder after 1 hour of use, with tools to tighten the moving knife, fixed knife screws, to strengthen the fixed between the blade and the knife frame; should be regularly filled with lubricating oil to ensure the lubrication between the bearings; to ensure the sharpness of the cutting edge of the tool, should always check the tool to ensure its sharpness, to reduce unnecessary damage to other parts caused by the blunt lack of the blade; regularly check whether the belt is loose, and timely tightening.
3. Restart - Before starting the plastic extruder for the second time, the remaining debris in the machine chamber should be cleared to reduce the starting resistance. Periodically open the inertia cover and pulley cover to clear the ash outlet under the flange, which can cause the powder to enter the shaft bearing.
4. Replacement parts - When replacing knives, the clearance between the moving and fixed knives should be 0.8 MM for crushers over 20 HP and 0.5 MM for crushers under 20 HP. The thinner the recycled material is, the gap can be adjusted appropriately larger.
If you need to know more, you can consult our company. The company focused on co-rotating twin-screw compounding extruders with the core of the various R&D and manufacturing, such as a twin-screw extruder, mini twin screw extruder, plastic extruder, parallel twin-screw extruder, and so on, the application covers compounding mixing modified granulation, polymerization, devolatilization, step molding, renewable 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.
Twin-screw extruders have barrels with an extension range of 4 and 6D, allowing for precise process design to meet specific customer requirements. All barrels allow for precise temperature control. Cooling is achieved by cooling water injection and high-performance electric heating rods for direct and fast heating. The auxiliary equipment of the twin-screw extruder consists of a straightening device, a preheating device, and a cooling and heating device. The following is a detailed description of the auxiliary equipment.
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l Straightening device
l Preheating device
l Cooling device
One of the most common types of plastic extrusion rejects is eccentricity, and bending of the wire core in various patterns is one of the most important causes of insulation eccentricity. In sheath extrusion, scratches on the sheath surface are also often caused by the bending of the cable core. Therefore, a variety of extrusion units in the straightening device is essential. The main types of straightening devices are roller type (divided into horizontal and vertical type); pulley type (divided into single pulley and pulley group); stranded pulley type, which plays a variety of roles such as dragging, straightening, and stabilizing tension; pressure pulley type (divided into horizontal and vertical type), etc.
Cable core preheating is necessary for both insulation extrusion and sheath extrusion. For the insulation layer, especially the thin layer of insulation, the existence of pores should not be allowed, the core can be completely removed from the surface of the water, oil, and dirt through high temperature preheating before extrusion. For the sheath extrusion, the main role is to dry the cable core, to prevent the role of moisture (or moisture around the bedding layer) to make the sheath in the possibility of porosity. Preheating can also prevent the plastic from being extruded due to sudden cooling and residual internal pressure. In the process of extruding plastic, preheating can eliminate the cold line into the high-temperature heat, in contact with the plastic at the mouth of the die to form a disparity in temperature, to avoid fluctuations in plastic temperature and lead to fluctuations in extrusion pressure, to stabilize the amount of extrusion and ensure the quality of extrusion. Extrusion unit is used in the electric heating core preheating device, requires sufficient capacity, and ensures rapid temperature rise, so that the core preheating and cable core drying efficiency. The preheating temperature is restricted by the speed of wire release, generally similar to the temperature of the head.
The formed plastic extrusion layer after leaving the head should be immediately cooled and shaped, otherwise, deformation will occur under the action of gravity. The way of cooling usually uses water cooling, and according to the water temperature is different, divided into rapid cooling and slow cooling. Rapid cooling is the direct cooling of cold water, rapid cooling of plastic extrusion layer sizing is beneficial, but for crystalline polymers, due to sudden heat cooling, easy to internal residual stress in the extrusion layer organization, resulting in the use of the process of cracking, general PVC plastic layer using rapid cooling. Slow cooling is to reduce the internal stress of the product, in the cooling water tank placed in sections of different temperatures of water, so that the product gradually cool down and set, PE, PP extrusion on the use of slow cooling, that is, after hot water, warm water, cold water three cooling.
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The twin screw extruder's standard equipment includes a sturdy base frame dedicated to housing the temperature control unit and oil lubrication system. The equipment features advanced control software for seamless integration into digital factories, ready for Industry 4.0, greatly improving ease of use. The following is a detailed description of the operating procedures of the twin screw extruder.
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l Start up operation
l Stop the machine
Start up operation
1.Close the power main gate of the twin screw extruder.
2. Turn on the power at the operation panel: Press and hold the power button clockwise to turn and then release.
3. Set the temperature of each temperature zone: for example, a zone temperature according to the process requirements set the corresponding temperature, press the set button, and then adjust the up and down arrows to the desired temperature, press the set button.
4. Set the feeding rate: according to the process, requirements can be fed rate between 0 ~ 10 to set.
5. Set the host speed of the twin screw extruder: set the host speed between 0~30 according to the process requirements.
6. Add cooling water to the cooling tank.
7. In turn on the fan: press the operation button on the operation panel.
8. When you need to start the operation of the vacuum pump, you can start the vacuum pump.
9. Turn on the cutter switch.
1. Twin screw extruder normal stopping sequence: stop the feeder: close the vacuum line valve, open the vacuum chamber on the cover; gradually reduce the main screw speed; shut down the pelletizer and other auxiliary equipment: off the motor, each external water inlet valve.
2. Twin screw extruder emergency stop: (1) in case of an emergency need to stop the host, you can quickly press the electrical control cabinet red emergency stop button, and the host and the feed speed knob back to zero, and then the total power switch off. After eliminating the fault, you can restart the machine again in normal driving order. (2) encounter equipment automatic protection trip stop: need to set the various parameters knob to zero, and then reset the parameters, press the reset button and start the machine again.
1. The normal production of the first shift machine, be sure to first check whether the barrel, hopper seal is the original closed kind, such as changes or damage, should check the hopper, the machine inside the Jane there are no foreign objects.
2. Pay attention to the screw to start at a low speed, the air time can not exceed 3min.
3. Must pay attention to check the purity of each batch of material, do not allow any impurities mixed into the material.
4. The beginning of the material to pay attention to the first small amount, evenly added material, while paying attention to observe the current meter (torque meter) pointer changes.
For granular material, use metering to add material. When you first start to feed production, be sure to pay attention to the extruder production work overload phenomenon. After the forming die lip out of the material, and then gradually increase the screw speed as appropriate.
5. Often check the working condition of the motor carbon brush, abnormalities should be replaced or adjusted promptly.
6. The screw cleaning work is not allowed to use steel tools scraping material, the application of copper brush, shovel cleaning.
7. When the process temperature is suspected of displaying problems on the instrument, use mercury temperature, meter actual measurement of the machine Jane, and molding mold degree. Refer to the mercury temperature measured temperature, adjust the calibration instrument to show the temperature.
If you still have questions, you can consult our company. Our company's website is https://www.njjyextrusion.com/
The composition of the single screw extruder: mainly consists of servo motor, reduction box, screw cylinder, nozzle head, filter air, heating and cooling system, touch screen, and SPS control. It is the extrusion host to form.
What are the reasons why the main engine of the single screw extruder cannot be started and the solutions?
What are the reasons and solutions for the high inlet flow of the single screw extruder?
What is the design concept of the single screw extruder?
(1) The driving program of the single screw extruder is wrong.
(2) There is a problem with the main engine thread and whether the fuse is blown.
(3) The locking device for the single screw extruder and the main engine works.
(1) Check the program of the insert extruder and restart in the correct order.
(2) Check the main engine circuit.
(3) Check whether the lubricating oil pump has started and check the status of the locking device concerning the main engine. The oil pump cannot be turned on and the engine cannot be turned on.
(4) The inverter has not discharged the induction current, turn off the main power supply and wait five minutes before starting.
(5) Check if the emergency button of the single screw extruder has been reset.
1. Reasons: (1) The single screw extruder has an insufficient heating time and a large torque. (2) A certain section of the heating does not work.
2. Treatment method: (1) Use the handwheel when driving the single screw extruder. If it is not easy, extend the heating time or check that the heaters of the individual sections work properly.
The main engine makes an abnormal noise:
1. Reasons: (1) Main engine stock damaged. (2) A specific SCR in the SCR DC power supply of the main engine is damaged.
2. Treatment method: (1) Replace the main engine stock of the single screw extruder. (2) Check the thyristor alignment and replace the thyristor component if necessary.
1. High-speed and high-Yield extrusion based on high quality.
2. The design concept of low-temperature plasticization ensures the extrusion of high-quality products.
3. The two-stage overall design of the single screw extruder reinforces the plasticization function to ensure the adjustment of the high-performance extrusion.
4. Special barrier, comprehensive mixing design to ensure the mixing effect of materials.
5. High torque drop, extra-large pressure bearing.
6. Gears and shafts are made of high-strength alloy steel, cooled, and chipped.
7. High hardness, high finish, extremely quiet.
8. PLC-intelligent control can realize the connection between main and auxiliary machines.
9. The easy-to-monitor human-machine interface makes it easy to understand the processing and machine status.
10. The control method (temperature device) can be changed if necessary.
11. The material is 38CrMoAL/A nitric treatment, wear-resistant.
12 Strict temperature control accuracy, combined with air cooling and water cooling.
13. The single screw extruder has a unique inlet design and complete water cooling.
14. An single screw extruder with a grooved surface of the lower shell has an improved feed function that guarantees a high speed and a high yield of extrusion.
The single screw extruder is increasingly used in industrial production.Nanjing JlEYA has committed itself to offering the best-suited single screw extruders at a reasonable price, and all that is necessary to meet the needs of the customer.
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.
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Preparation work before starting the machine
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/
Plastic extruders can be divided into single-screw extruders, twin-screw extruders, and multi-screw extruders according to their number of screws. The following are the details of the types of plastic extruders.
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Classification of plastic extruders
Classification of plastic extruders
1, According to the number of screws, divided into single-screw extruders, twin-screw extruders, and multi-screw extruders.
2, According to the presence or absence of a screw in the extruder, divided into screw extruders and plunger extruders.
3, According to the running speed of the screw to divide:
Ordinary extruder: speed below 100r/min.
High-speed extruder: speed of 100 to 300r/min.
Super high-speed extruder: the speed is 300~l500r/min.
4, According to the extruder assembly structure classification: there are integral extruders and separate extruders.
5, According to the spatial position of the screw in the extruder, can be divided into the horizontal extruder and vertical extruder.
6, According to whether the extruder is in the process of exhaust and can be divided into exhaust type extruder and non-exhaust type extruder
The single-screw extruder occupies an important position both as a plasticizing and pelletizing machine and as a molding machine, and in recent years, the single-screw extruder has developed greatly. Single-screw extruders were the first extruders to gain widespread application in the plastic processing and molding field due to their simple structure and high processing efficiency. Similarly, to meet different processing needs, various equipment manufacturers have explored various screw and barrel structures. The single-screw extruder has evolved from the basic pure screw structure to various structures such as damping screw block, exhaust extrusion, slotted screw barrel, pinned barrel, building block structure, etc., thus enabling the single-screw extruder to have a wider range of molding.
Due to the small footprint of single-screw extruders, they are almost the only equipment used in the compounding and blown film fields. Single-screw extruder technology has become an important part of the extrusion process market that cannot be ignored.
The twin-screw extruder has less heat generated by friction, more uniform shearing of the material, larger conveying capacity of the screw, more stable extrusion volume, long stay of the material in the barrel, and uniform mixing.
The twin-screw extruder has good feeding characteristics, is suitable for powder processing, and has better mixing, exhaust, reaction, and self-cleaning functions than the single-screw extruder, characterized by the processing of plastics with poor thermal stability and co-mingled materials show its superiority. Based on the twin-screw extruder, the multi-screw extruder was developed for easier processing of co-blends with poor thermal stability.
If you want to buy an 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, after 17 years of development, now we have 20,000 square meters workshop with annual sales over 300+ sets, export over 60 countries.