The engineering plastic twin screw extruder consists of a transmission device, a feed device, a barrel, and a screw. The function of each component is similar to that of a single-screw extruder. The difference to the single screw extruder is that in the engineering plastic twin screw extruder two parallel snails are arranged in the "cross-section" of the material.
What is the working principle of the engineering plastic twin screw extruder?
How do you treat a engineering plastic twin screw extruder?
Why is the cooling device particularly important when using engineering plastic twin screw extruders?
From the point of view of the principle of movement, the engineering plastic twin screw extruder distinguishes between the straight and uneven, and non-foaming types.
1. Double screw extruder of technical plastic
This type of engineering plastic twin screw extruder has a low speed and a high speed. The former is mainly used for profile extraction, while the latter is used for special polymer processing operations.
(1) Tightly machined extruder. The slow-running extruder has a closely combining screw geometry, in which the spiral antenna shape of one snail closely matches the spiral antenna shape of the other snail, i.e. the conjugated snail shape.
(2) Self-cleaning extruder. The simultaneous high-speed extruder has a closely tuned spiral shape. This type of snail can be executed with a relatively small snail split so that the snail has a closed self-cleaning effect. This type of engineering plastic twin screw extruder is called a compact self-cleaning engineering plastic twin screw extruder.
The gap between the two screw edges of the closely combining, opposing engineering plastic twin screw extruder is very small (much smaller than the gap in the evenly rotating engineering plastic twin screw extruder) so those positive conveying properties can be achieved.
2. Non-reciprocating double screw extruder of technical plastic
The axis distance between the two snails of the non-foaming engineering plastic twin screw extruder is greater than the sum of the radii of the two snails.
1. After using the engineering plastic twin screw extruder for 500 hours, iron chips or other impurities from the gears are in the gearbox. Therefore, the gears should be cleaned and the gear lubricant replaced.
2. The engineering plastic twin screw extruder should carry out a comprehensive inspection of the extruder after an operating period to check the density of all snails.
3. If the double screw extruder is suddenly switched off during production, the main drive, and the heating stops, if the power supply is restored, each section of the cylinder shall be reheated to the specified temperature and kept for a specified period, before you can start the extruder.
4. If the display and the display of the engineering plastic twin screw extruder are full, check if the contact of the thermocouple, etc. is good.
After the molded plastic extrusion layer has left the engineering plastic twin screw extruder, it should be cooled and formed immediately, otherwise, it will deform under the influence of gravity. The cooling method normally uses water cooling and is divided into quick cooling and slow cooling according to the different water temperatures. Fast cooling is the direct cooling by cold water. Rapid cooling is advantageous for the design of the extruded plastic layer, but in the case of crystalline polymers, due to sudden heat cooling, it is easy to leave internal stresses in the extruded layer structure, which leads to cracks during use. Generally PVC The plastic layer is deterred. Slow cooling should reduce the inner tension of the product. Water with different temperatures is given in the cooling water tank to gradually reduce the temperature and shape of the product. The extrusion of PE and PP takes place under slow cooling, i.e. through hot water, hot water, and cold water, which is called three-stage cooling.
Nanjing JlEYA is the leading manufacturer extruder manufacturer specializing in twin screw extrude. If you want to get more information, just go and connect them.
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.
A twin screw extruder is composed of several parts such as a transmission device, feeding device, barrel, and screw, etc. The role of each part is similar to that of the single screw extruder. So what are the main differences between the twin screw extruder and single screw extruder? The following is the detailed introduction
Here is the content list:
l Cross sectional profile
l The way of material transfer
l The material flow velocity field
The difference from the single screw extruder is that the twin screw extruder has two parallel screws in an "∞" shaped cross section. Twin screw extruders for profile extrusion are usually closely meshed and heterogeneously rotating, although a few also use co rotating twin screw extruders, which generally operate at relatively low screw speeds of about 10 r/min. High speed meshing co rotating twin screw extruders are used for blending, venting, or as continuous chemical reactors, with maximum screw speeds ranging from 300 600 r/min. Non engaging extruders are used for mixing, venting, and chemical reactions, and their conveyors are very different from those of engaging extruders, and are closer to those of single screw extruders, although they are fundamentally different.
In the single screw extruder, the solid conveying section is friction dragging and the melt conveying section is viscous dragging. The frictional properties of solid materials and the viscosity of molten materials determine the conveying behavior. If some materials have poor frictional properties, it is more difficult to transfer the material to the single screw extruder if the feeding problem is not solved. In twin screw extruders, especially meshing twin screw extruders, the material transfer is to some extent a positive displacement transfer, the degree of positive displacement depending on the proximity of the screw prongs of one screw to the relative screw grooves of the other screw. The screw geometry of a closely meshed anisotropic rotary extruder yields a high degree of positive displacement transport characteristics.
The flow velocity distribution of the material in a single screw extruder has been described fairly well, whereas the flow velocity distribution of the material in a twin screw extruder is quite complex and difficult to describe. Many researchers have analyzed the velocity field of the material without considering the material flow in the engagement zone, but the results of these analyses are very different from the actual situation. This is because the mixing characteristics and overall behavior of a twin screw extruder depend mainly on the leakage flow that occurs in the engagement zone, yet the flow in the engagement zone is quite complex. The complex flow spectrum of the material in a twin screw extruder exhibits macroscopic advantages that cannot be matched by a single screw extruder, such as adequate mixing, good heat transfer, high melting capacity, good venting capacity, and good control of the material temperature.
If you want to know more, you can consult our company. 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, etc. After 17 years of development, now we have a 20,000 square meters workshop with annual sales of over 300+ sets, export over 60 countries.
JIEYA has the most experienced technical core team, with extensive experience in system integration of the development manufacturing, materials processing, application technology, and other fields.
A plastic extruder performs all of the following processes through a barrel with a screw and auger channel. The plastic pellets enter the barrel through a hopper at one finish of the barrel and are then transferred through the screw to the opposite finish of the barrel. What are the working principle and molding principles of a plastic extruder? The following is a detailed description.
Here is the content list:
Pressure and shearing, etc., convert the solid plastic into a uniform and consistent melt and send the melt to the next process. The production of the melt involves processes such as mixing additives such as masterbatches, blending resins, and re-crushing. The finished melt must be homogeneous in consistency and temperature. The pressurization must be high enough to extrude the viscous polymer.
To have sufficient pressure, the depth of the threads on the screw decreases as the distance to the hopper increases. The external heating and the internal heat generated in the plastic and the screw due to friction softens and melts the plastic. The design requirements for plastic extruders often vary from polymer to polymer and from application to application. Many options involve discharge ports, multiple loading ports, special mixing devices along the screw, cooling and heating of the melt with or without an external heat source (adiabatic plastic extruders), the relative size of the gap variation between the screw and the barrel, and the number of screws. For example, twin-screw plastic extruders allow for more thorough mixing of the melt than single-screw plastic extruders. Tandem extrusion uses the melt-extruded from the first plastic extruder as feedstock for the second plastic extruder, which is typically used to produce extruded polyethylene foam.
D L the characteristic dimensions of plastic extruders are the diameter of the screw (D) and the ratio of the length of the screw (L) to the diameter D L/D (D) (L/D. Plastic extruders usually consist of at least three segments. The first section, near the L/D) filling hopper, is the filling section. Its function is to allow the material to enter the plastic extruder at a relatively smooth rate. In general, this section will be kept at a relatively low temperature to avoid clogging the charging channels. The second section is the compression section, where the melt is formed and the pressure is increased. The transition from the charging section to the compression section can be abrupt or gradual (gentle). The last half, the metering section, is adjacent to the plastic extruder outlet and its main operate is that the uniformity of the fabric flowing out of the plastic extruder. In this section, the material should have sufficient residence time to ensure uniformity of composition and temperature.
At the end of the barrel, the plastic melt leaves the plastic extruder through a head that is designed in an ideal shape for the extruded melt stream to pass through.
Another important part is the drive mechanism of the plastic extruder. It controls the rotational speed of the screw, which determines the output of the plastic extruder. The power required is determined by the viscosity (flow resistance) of the polymer. The viscosity of the polymer depends on the temperature and flow rate and decreases with increasing temperature and shear. Plastic extruders are equipped with screens that keep impurities out of the screen. To avoid downtime, the screens should be able to be changed automatically. This is especially important when processing resin with impurities, such as recycled material. The extruder's screw is divided into feeding section, plasticizing, melting section, temperature according to the process parameters of the plastic particles, the model according to the diameter of the screw 20, 36, 52, 65, 75, 95, 120, 135. Plastic particles heated by the movement of the screw to change the original state, there are many types, depending on the specific application. The capacity of the frequency conversion is proportional to the diameter of the screw and then adjusted according to the different raw materials.
The extrusion method of plastic extruders generally refers to the melting of plastic at a high temperature of about 200°C. The melted plastic is then passed through a die to form the desired shape. Extrusion molding requires a deep understanding of the characteristics of plastics and extensive experience in mold design and is a technically demanding molding method.
Extrusion molding is a method of a continuous flow of material through a die by heating and pressurizing in an extruder, also known as "extrusion molding". Compared with other molding methods, it has the advantages of high efficiency and low unit cost.
Extrusion is mainly used for molding thermoplastics, but it can also be used for some thermosets. Extruded products are continuous profiles, such as tubes, rods, wires, sheets, films, wire, and cable cladding, etc. In addition, it can also be used for mixing, plasticizing and granulating, coloring, blending, etc. plastics.
The extruded products can be called "profiles", which are also called "profiles" because of their irregular cross-sectional shape.
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.
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.
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Nanjing Jieya Extrusion Equipment Co., Ltd. (referred to as "Jieya") was established in 2004. It has the manufacturing capacity of various types of production lines with an annual production and sales of more than 350 sets. Its comprehensive capability ranks in the forefront of the Nanjing twin screw extruders industry. The company focuses on the R&D and manufacturing of various production lines centered on co-rotating twin-screw extruders and single-screw extruders. The product applications cover compounding, modified granulation, polymerization, devolatilization, one-step molding, and recyclable resources, etc.
Project Director Mr Chen introduced that every industry has competition, but specific to a certain market segment, the competitors involved are different. Traditional physical blending and modification is the largest market for twin-screw extruders, so the competition is the most intense. For Jieya, the bio-degradable plastic market was changed greatly in 2021, and a considerable part of Jieya’s orders in 2021 also came from this market.
Mr Chen explained that the reason why bio-degradable plastics are singled out from the traditional blending and modification market is that there have been many entrants in this market in the past two years, which has led to the rapid expansion of the market scale. Therefore, from traditional compounding and extrusion to processing bio-degradable plastics, is it necessary to carry out certain technical reserves? Mr Chen said frankly that it depends on how much bio-degradable plastics companies want to achieve. Just like melt blown materials in 2020, some companies have astonishing shipments, and some companies choose to take the quality to a higher level. The bio-degradable material made by special equipment must be of higher quality.
Around 2010, Jieya began to get involved in bio-degradable-related projects. During this period, we saw the ups and downs of major companies, and also witnessed the gradual growth of some companies from small to large. Most of these surviving companies are in the bio-degradable market. They started foreign trade before they became popular, and some companies even achieved a market share of about 30% in the export of Chinese vest bags.
He also talked about some distressing points in the biodegradable market: at present, the Chinese government has not clearly stipulated the definition and criteria of "bio-degradable". For example, some regions regard photo-degradable as a kind of bio-degradable. Many people oppose this. Mr Chen said that at present, most people in the Chinese market think that 'bio-degradable' is compostable and degradable, and garbage must be sorted and recycled before composting is possible.
However, Mr Chen is still very optimistic about the development of bio-degradable plastics. Bio-degradable must be the general trend of future social development, but the specific direction remains to be verified. Jieya has a layout for the main bio-degradable plastic categories, such as targeting for many PBAT projects launched in China in the past two years, we are actively discussing with customers whether we can directly use the twin-screw extruder in the polymerization stage to directly make modified materials (without extruding PBAT raw materials). Jieya has also followed up on the project of carbon dioxide production of PPC bio-degradable materials and PGA synthesized with glycolide. At present, the bio-degradable plastics market is still developing and improving. What we need to do now is to develop the corresponding twin-screw technology with the industrial chain. Based on the accumulated experience of a large number of practical applications to continuously improve the stability of the equipment.
Under the big goal of carbon neutrality, some very big changes have taken place in industries such as home appliances and automobiles. The intuitive impact is that Jieya has recently received some projects for recycling, dismantling, and regranulating waste household appliances, as well as the crushing, recycling, and regranulation of some new energy battery shells, which is also one of the important markets for Jieya in 2021. Mr Chen said that these manufacturers have multiple production lines and large projects, but they are usually new entrants, and usually require suppliers to provide them with whole-plant project planning, so they put forward higher requirements for suppliers' project experience and service capabilities.
Fluorochemicals, another key application area for which Jieya is recognized. Fluoroplastics are also known as "plastic kings". Their corrosion resistance, solvent resistance, weather resistance and temperature resistance are relatively good, so they are often included in the field of special engineering plastics. The most well-known is the PVDF used with lithium battery binder. In 2021, Jieya also undertook some projects in this field.
Mr Chen believes that the Chinese market is developing very fast, and twin-screw extruder enterprises must keep abreast of customer needs in order to gain a foothold in the market. Therefore, Jieya is also seeking new development in the upstream links. For example, the twin-screw devolatilization extrusion unit developed to meet the growing demand of downstream customers for products with low VOC and low residue; as well as corrosion resistance and wear resistance under high temperature conditions. The extrusion unit meets the production needs of special products under severe working conditions.
The success of Nanjing Jieya in the market is inseparable from the technical advantages of its twin-screw extruder equipment: its core components are all self produced, including high-torque gearboxes, extruder barrels, extruder screw elements, screen changer, die, etc. The product quality is stable and controllable, which can meet the personalized customization needs of customers, and the delivery time is flexible. In addition, Jieya stable team has also played a huge advantage. It is said that its sales, technology, management, and after-sales teams have an average of more than 10 years of experience in the industry. They have rich industry experience and are relatively clear about the pain points of various market segments. Provide complete personalized solutions, and can also undertake large and complex complete system projects.