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.
Here is the content list:
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.
If you are engaged in a twin-screw extruder-related industry, you can consider our cost-effective products.
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
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/
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 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/
The extrusion technology used by the single screw extruder is making waves in the food production industry. We know that single screw extruder can mass produce enterprise products of various shapes and textures. It allows a seamless and continuous operation process, which means that this means lower costs and higher production and sales.
What are the reasons and solutions for the poor discharge or blockage of the single screw extruder head?
What is the importance of single screw extruder temperature control?
What is the importance of single screw extruder speed control?
1. Reasons: (1) A certain section of the heater does not work, and the material is poorly plasticized. (2) The operating temperature is set too low, or the molecular weight distribution of the plastic is wide and unstable. (3) There may be foreign objects in the single screw extruder that are not easy to melt.
2. Treatment method: (1) Check the heater and replace it if necessary. (2) Verify the set temperature of each section, negotiate with the technician if necessary, and increase the temperature set value. (3) Clean and check the extrusion system and head of the single screw extruder.
Temperature control refers to the temperature of the single screw extruder during plastic extrusion, including the temperature control of the barrel, die and transition body. These temperature controls are related to the viscosity of the material, the sensitivity to temperature, and the aggregation state of the polymer. In general, the temperature of the die head and transition body of single screw extruder is low for medium and low viscosity materials, and the temperature of die head and transition body for high viscosity materials is high, and the fluidity is good.
Speed control means that for single screw extrude processing, if the screw speed increases, the shear rate increases. Thermoplastic melts are mostly non-Newtonian pseudoplastic fluids, and their viscosity decreases with the increase of shear rate, and fluidity Increasing the extrusion output also increases. However, if the shear rate is too large, the melt viscosity is too low, which will cause difficulties in the production and operation of single screw extrude. At the same time, the low-viscosity melt will flow backwards under the action of the screw back pressure, and the leakage flow will increase significantly, which will affect the output to a certain extent. , Again, the screw may even slip at high speeds, so the screw speed should be controlled within a certain range. In addition, in the production process of single screw extrude, the screw speed should be kept as stable as possible to avoid fast and slow. Otherwise, it will cause uneven discharge due to excessive changes in the melt viscosity of the material, which will affect normal production.
Nanjing JlEYA is a single screw extruder manufacturer established for more than five years. We work with customers from design to completion to ensure that all technical requirements are met.
Material delivery method
In a single-screw extruder, there is friction drag in the solids conveying section and viscous drag in the melt conveying section. The friction properties of the solid material and the viscosity of the molten material determine the conveying behavior. If some materials have poor friction properties, if the feeding problem is not solved, it will be difficult to feed the materials into the single-screw extruder. In twin-screw extruders, especially intermeshing twin-screw extruders, the conveying of materials is to some extent forward displacement transmission, and the degree of forward displacement depends on the relationship between the flight of one screw and that of the other screw. the proximity of the relative screw grooves. The screw geometry of the closely intermeshing counter-rotating extruder results in a high degree of positive displacement delivery characteristics.
Material flow velocity field
At present, the flow velocity distribution of the material in the single-screw extruder has been described quite clearly, while the flow velocity distribution of the material in the twin-screw extruder is quite complicated and difficult to describe. Many researchers just do not consider the material flow in the meshing area to analyze the flow velocity field of the material, but these analysis results are very different from the actual situation. Because the mixing characteristics and overall behavior of a twin-screw extruder are primarily determined by the leakage flow that occurs in the intermeshing zone, the flow situation in the intermeshing zone is quite complex. The complex flow spectrum of the material in the twin-screw extruder shows macroscopic advantages that the single-screw extruder cannot match, such as sufficient mixing, good heat transfer, large melting capacity, strong exhaust capacity and good temperature control of the material, etc.
The Underwater pelletizing machine cuts pellets on the plastic steel ejection surface without centrifugal action to eject them, but direct water pressure flows through the nozzle surface to drain.
What is contained in the extrusion system of the Underwater pelletizing machine?
What is the use of the Underwater pelletizing machine?
What are the causes and solutions for the high melting of the Underwater pelletizing machine?
The extrusion system includes a snail, a cylinder, a funnel, a nozzle, and a nozzle. Through the extrusion system, the plastic is plasticized into a uniform melt and continuously extruded by the screw under the resulting pressure.
(1) Screw: It is the most important part of the Underwater pelletizing machine. It is directly related to the scope and productivity of the extruder. It consists of high-strength corrosion-resistant alloy steel.
(2) Cylinders: The cylinder is a metal cylinder that is generally made of alloy steel or composite steel tubes clad with alloy steel, heat resistant, high-pressure resistant, strong, wear-resistant, and corrosion-resistant. The cylinder and the screw are matched to each other to realize the crushing, grinding, melting, plasticization, suction, and compaction of the plastic as well as the continuous and uniform supply of the rubber material to the molding system. In general, the barrel length of an Underwater pelletizing machine is 15-30-fold its diameter, so that the plastic is completely heated and plasticized.
Underwater pelletizing machines can be used for chemical fertilizers, white soot, inorganic salts, chlorinated isocyanic acid, bleaching powder, pesticides, oxides, etc. as well as for industrial recycling dust: such as cast iron dust, lead, zinc, aluminum dust, converter dust, filter dust, grinding dust, etc. The material is forced to be pressed and molded by mechanical pressure without adding a net, and the purity of the product is guaranteed. The process process process is short, energy consumption is low, and performance high. The dry powder is directly granulated without a subsequent drying process, which is more conducive to the connection and transformation of the existing production process. The granular strength is high and the increase in bulk density is more significant than in other granulation processes. The Underwater pelletizing machine is particularly suitable for occasions to increase the specific weight of the product collection. The operating flexibility is great, the range of applications is wide and the crushing force can be adjusted by hydraulic pressure.
Causes analysis: high filter masks, low melting index of polypropylene powder and high feed volume, low temperature of each section of the Underwater pelletizing machine results in the material being incompletely melted, and a low opening rate of the template impede the extrusion of the nozzle head material, etc. The reasons may cause the melting pressure to be too high.
Solution: If the Underwater pelletizing machine produces products with a low melting index, a filter with a low mesh width should be used and the throttle opening should be enlarged to reduce backpressure; the filter should be replaced in time and the quality of different additives and polypropylene powder should be monitored. Contains medium ash. Reduce the feed load. Without compromising the quality of the extruded product, increase the temperature of each section of the cylinder to increase the temperature of the polypropylene melt and increase the flow capacity of the material. After the extruder has been stopped, increase the temperature of the head of the Underwater pelletizing machine and keep it at a constant temperature for a while and rinse and then thoroughly clean the template.
The underwater pelletizing machine have been used in many fields Nanjing JlEYA maintains close relationships with customers in underwater pelletizing machine industry, and is committed to strengthening production and operation, improving quality and safety.
PVC compounding extruder is made by mixing PVC resin with stabilizers, lubricants, and other additives through granulation and then extrusion, or by using powder in one extrusion. what are the application areas of PVC? The following are the details.
Here is the content list:
General soft products
PVC foam products
PVC coated products
PVC paste resin
PVC transparent sheet
PVC rigid sheet
Other applications of PVC
General soft products can be extruded into cables, wires, and hoses by the extruder: shoe soles, slippers, various plastic sandals, as well as toys and auto parts by the injection molding machine with various molds.
PVC film After mixing and plasticizing PVC with additives, transparent or colored film of specified thickness can be made by using a three-roller or four-roller calendar, and calendered film can be processed by this method. It can also be cut and heat laminated to process raincoats, tablecloths, curtains, packaging bags, inflatable toys, etc. The wide transparent film can be used for greenhouse, plastic shed, and ground film; the film stretched in both directions can be used for shrink packaging due to its characteristics of shrinkage by heat.
Soft PVC can be used as sandals, insoles, foam slippers, and shockproof and cushioning packaging materials. In addition, it can also be extruded into low-foaming hard PVC sheets and profiles by extruder, which is a new type of building material and can be used as a substitute for wood.
Artificial leather with backing is made by coating PVC paste on cloth or paper and then plasticizing it at 100 degrees Celsius or above (or PVC and additives can be calendered into film and then pressed together with backing); while artificial leather without backing is directly calendered by calender into soft sheet with a certain thickness and then pressed with the pattern. It can be used to make leather bags, leather boxes, book covers, sofas, and car cushions, etc. It can also be made into flooring leather, which is used as the flooring material for buildings.
PVC emulsion or micro-suspension resin is dispersed in a liquid plasticizer to make it swell and plasticize into the plasticized sol, and then add stabilizer, filler, coloring agent, etc. After full stirring for de-bubbling, PVC paste is prepared, and then processed into various products such as coat hangers, tool handles, Christmas trees, etc. by casting, impregnating, or laminating processes.
Impact modifier and organotin stabilizer are added to PVC, which is mixed, plasticized, and calendered into transparent sheets. Then it can be made into thin-walled transparent containers by thermoforming and can be used for vacuum blister packaging such as moon cake boxes, etc. It is an excellent packaging material and decoration material.
PVC hard sheet and plate After adding stabilizer, lubricant, and filler to PVC and mixing, it can be extruded into various caliber hard pipes, shaped pipes, corrugated pipes, and other products by using an extruder, and used as a downpipe, drinking water pipe, electric wire casing or staircase handrail, etc.; the calendered sheet can be overlapped and hot-pressed to make various thicknesses of hard sheets, which can be cut into various desired shapes and can be welded into various chemical resistant tanks, ducts and containers by using PVC welding rod with hot air, etc.
PVC can be processed into rigid profiles using an extruder and used for window and door assembly. In some countries, the doors and windows assembled by PVC rigid profile have occupied the market of windows and doors together with wooden windows and doors, aluminum windows, etc.
If you want to buy PVC compounding extruder, 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.