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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.
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 film
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 engineering plastic twin screw extruder was developed based on a single screw extruder. Due to its good feed performance, mixing and plasticization performance, suction performance, and extrusion stability, it is often used in extruded products.
What are the advantages of engineering plastic twin screw extruders?
What role do pre-heaters play in the use of engineering plastic twin screw extruders?
What is the reason for the "fault" of the exhaust air opening of the engineering plastic twin screw extruder?
1. wear
By simply opening the engineering plastic twin screw extruder, the wear level of the threaded parts and the inner sockets of the cylinder can be determined at any time, so that we need to carry out effective maintenance or exchange. It is not detected if there is a problem with the extruded product causing unnecessary waste.
2. Reduce production costs
When a engineering plastic twin screw extruder is made of technical plastic Masterbatch, it is often necessary to change the color. It is necessary to change the product.
Simply open the open editing area within a few minutes. In addition, the mixing process can be performed by observing the melting profile on the entire screw. analysis. When changing the color of an ordinary engineering plastic twin screw extruder, a large amount of cleaning material is needed to clean the machine, which is time and energy consuming and wastes raw materials. The split engineering plastic twin screw extruder can solve this problem. When changing color, it takes only a few minutes to quickly open the barrel for manual cleaning, so that no or fewer cleaning agents can be used, which saves costs.
A pre-heating of the cable core is required for the use of an engineering plastic twin screw extruder. The presence of pores shall not be permitted for the insulating layer, in particular the thin insulating layer. The wire core can be completely removed from the water and oil surface by high-temperature preheating before crushing. In the case of coat extrusion, its main function is to dry the cable core to prevent the possibility of pores in the coat due to moisture (or moisture around the cushion layer). By preheating, the residual pressure of the plastic can also be prevented by discouragement during extrusion. During the plastic extrusion of the processor, preheating can eliminate the large temperature difference that occurs when the cold wire enters the high-temperature nozzle and the nozzle is in contact with the plastic, thereby avoiding the fluctuation of the plastic temperature and causing the fluctuation of the extrusion pressure. This stabilizes the extrusion volume and ensures the extrusion quality. The technical plastic engineering plastic twin screw extruder uses an electric radiator preheating device that requires sufficient capacity and guarantees rapid heating so that the core preheating and drying efficiency of the cable core is high. The pre-heat temperature is limited by the deflection speed and generally corresponds to the temperature of the machine part.
The temperature of the machine part is low and the pressure of the machine part is too high.
engineering plastic twin screw extruder The engineering plastic twin screw extruder used for profile extrusion is usually narrow-meshed and rotates in different directions, but a few also use simultaneous engineering plastic twin screw extruders, which usually work with relatively low screw speed. About ten U/min.
The rapidly combining, simultaneous engineering plastic twin screw extruder is used for composting, venting or as a continuous chemical reactor. The maximum snail speed of this extruder type is 300-600 U/min. The non-interactive extruder is used for mixing, venting, and chemical reaction. Its conveyor mechanism is very different from the interlocking extruder, which is closer to the conveyor mechanism of a single screw extruder.
These are related practices for using engineering plastic twin screw extruders. If you want to get more information about the engineering plastic twin screw extruders, please connect Nanjing JlEYA, and they will tell you more about it.
PVC compounding extruder is divided into RPVC pipe and SPVC pipe, RPVC pipe is easy to cut, welding, bonding, heating can be bent and therefore very easy to install and use. SPVC pipe has excellent chemical stability excellent electrical insulation and good flexibility and colorability this pipe is often used to replace rubber pipe to transport liquid and corrosive media also used as cable casing and wire insulation pipe, etc. So how do choose raw materials and the operation of PVC compounding extruder? The following is a detailed introduction
Here is the content list:
Raw material selection
Safety operating procedures
PVC compounding extruder in the production of hard pipe resin should be selected from the lower polymerization degree of SG-5 resin polymerization degree of the higher its physical and mechanical properties and heat resistance is better, but the resin liquidity is poor to bring some difficulties in processing, so generally choose viscosity of 1.7 ~ 1.8 × 10-3Pa-s SG-5 resin is appropriate. Hard pipe generally uses lead-based stabilizers whose thermal stability is good commonly used trisodium lead but its lubricity is poor usually and good lubricity of lead, barium soap type and use. Processing hard tube lubricant selection and use are very important to consider both internal lubrication to reduce intermolecular forces to reduce the viscosity of the melt are conducive to molding and to consider external lubrication to prevent the melt and hot metal adhesion to make the product surface shiny. Internal lubrication is generally used metal soap type external lubrication with low melting point wax. Filler mainly with calcium carbonate and barium barite powder calcium carbonate to make the pipe surface performance of good barium can improve the molding of the pipe easy to shape both can reduce costs but the amount of too much will affect the performance of the pipe pressure pipe and corrosion-resistant pipe is best not to add or add less filler.
1. Personnel without induction test and operation training cannot operate the extruder independently.
2. People who have poor eyesight and slow response can not be on duty to operate.
3. Before starting the machine to do a good job of environmental health around the PVC compounding extruder equipment, equipment around the pile of items not related to production.
4. Check the safety settings of the extruder before production for damage and test whether it can work effectively. Check whether the connection bolts are loose and whether the safety guards are firm.
5. Check the lubrication parts, remove the dirt, and refill the lubricant.
6. PVC compounding extruder barrel and die heating constant temperature time to ensure that the material temperature does not reach the process requirements when driving production.
7. Before starting the screw drive motor to use the hand plate support V pulley, should be flexible rotation, no blocking phenomenon; then start the lubricating oil pump work 3min before starting the screw rotation at low speed.
8. Screw airlift time should not exceed 2 ~ 3min.
9. PVC compounding extruder barrel before adding material to check the barrel, hopper, there is no foreign matter; raw materials should be free of metal, sand, and other impurities to Prevent damage to the screw.
10. The screw starts, the transmission parts work sound normal, the main motor current within the allowable rated value, before allowing the barrel to add material, adding material should first be a small amount of evenly added material.
11. When adjusting the die gap or clearing the dirty material, the operator should wear gloves and not face the barrel and die to prevent the molten material from spraying out of the die and scalding the body.
12. Extruder driving operation is not allowed to repair, and no one is allowed to do any work on the equipment at this time.
13. In case of the following phenomena, should be an emergency stop.
Bearing parts of the high temperature, lubricating oil (grease) out; motor odor, smoke, or shell temperature is too high; speed box lubricating oil temperature, smoke; transmission parts emit irregular abnormal sound; machine work produces violent vibration; screw suddenly stop rotating.
14. PVC compounding extruder equipment on the safety cover and the location of the safety alarm device is not allowed to change at will, not to mention artificially caused by the malfunction.
15. Find that the equipment leakage, oil leakage phenomenon should be timely maintenance troubleshooting, no water, oil flow around the machine.
If you have questions about how to use the PVC composite extruder, you can contact us on the official website. We are happy to answer for you.
The twin screw extruder has the basic principles of single-screw extruder: solid conveying, melt pressurization and pumping, mixing and stripping and evaporation, but it is not limited to this. The development of twin screw extrusion theory is relatively late, coupled with its wide variety, messy screw shape, and messy extrusion process, which brings many difficulties to the research. And the following words will give you a brief introduction about the information of the twin screw extruder.
What is the future research direction of twin screw extruder?
What is the basic principle of a twin screw extruder?
What is the difference between a twin screw extruder and a traditional extruder?
1. Established the physical model and mathematical model of the twin screw extruder to guide the design of the twin screw extruder and the optimization of the extrusion process.
2. It is necessary to understand the relationship between the true state change, the mixing form, the whole process of the structure change and the later mixing and characteristics of two or more polymers and materials during the entire extrusion process.
3. As a twin screw extruder, it establishes the internal connection between the entire reaction process, speed and characteristics of the extrusion reaction molding and the screw structure and operating conditions. It can be extruded through reaction molding.
The twin screw extruder has the basic principles of single-screw extruder: solid conveying, melt pressurization and pumping, mixing and stripping and evaporation, but it is not limited to this. The development of twin screw extrusion theory is relatively late, coupled with its wide variety, messy screw shape, and messy extrusion process, which brings many difficulties to the research.
Generally speaking, the research of twin-screw extrusion theory is still in the development link, which is called "technology more than science". From the perspective of the entire extrusion process of a twin screw extruder, there are about three parts: the polymer's physical state change rule during the extrusion process, the basic principle of conveying, the conveying of solid melt, the exhaust phase and the law, and the establishment of mathematics The physical model is used to guide the planning of the twin screw extruder and the optimization of the extrusion system process.
The traditional extrusion molding process requires rotating a giant screw in the barrel. When using twin screw extrusion, the two screws mesh with each other and rotate together during the extrusion operation. They are installed in the housing on the spline shaft of the barrel. The twin screw extruder can simultaneously ensure food molding, heating, cooling, compression, mixing, pumping and even transportation.
At present, twin screw extruder has become the most common extruder with the largest variety and specifications in the world. Nanjing JlEYA has committed to fulfilling all the requirements of twin screw extruders. And it welcomes global customers to purchase.
2022 Chinese Mid-autumn festival is coming.
Jieya team wish you happy mid-autumn festival and enjoy your holiday!!
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
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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.