The single screw extruder is mainly used for extruding soft and hard polyvinyl chloride, polyethylene, and other thermoplastic. It can be a variety of plastic products such as bubble sheets, extruded pipes, press plates, ribbons, etc. process and can also be used for melting granulation. The plastic extruder is characterized by advanced design, high quality, good plasticization, and low energy consumption. It uses an evolutionary drive and is characterized by low noise development, stable operation, great durability, and long service life.
What are the relevant parameters of a single screw extruder?
What are the properties of a single screw extruder?
For which materials can a single screw extruder be used?
The relevant parameters of the insertion extruder are arranged from left to right: the first field is the plastic machine code as S; the second box is the extruder code as J; the third field is the code for the different construction firms of the extruder. The three bars are combined, the plastic extruder is SJ; the ventilated plastic extruder is SJP; the plastic foam extruder is SJF; the extruder with plastic input is SJW; the plastic shoe extruder is SJE; The cascade plastic extruder is SJJ; the double-screw extruder is SJS; the conical double-screw extruder is SJSF; the multi-screw extruder is SJD. The fourth box is for auxiliary machinery with the code name F; in the case of an extruder unit with the code name E. The fifth parameter refers to the snail diameter and the ratio of length to snail diameter. The sixth field refers to the product's pattern sequences, which in the order of letters A, B, C... is arranged and the sample number is not given in the first sample.
(1) The material support of the inlet extruder is mainly based on friction, which limits the conveyance performance of the inlet extruder. The addition of powder, paste, fiberglass, and inorganic fillers is difficult.
(2) If the head pressure of the inlet extruder is high, the counter current increases, which reduces the productivity of the inlet extruder.
(3) Injected exhaust gas extruder material has a low surface regeneration effect in the suction zone, so the suction effect of the inlet extruder is poor.
(4) Injection extruder is used for certain processes, such as polymer dyeing, heat-resistant powder processing, etc. not suitable. The single screw extruder is a high-speed and high-yield extrusion based on a high level.
single screw extruder series, single screw extruders can be used for the processing of PP, PE, PS, ABS, PMMA, PVC, and other thermoplastic tubes, plates, plates, rods, profile materials, and plastic granulation products. For different raw materials and product specifications, the screw assumes different length-diameter ratios and compression ratios, and the flow assumes different structures. Choose the right cylinder, screw, and drive mechanism to meet the processing requirements of high-quality products.
The use of single screw extruders is becoming increasingly widespread. Nanjing JlEYA has been concentrating on single screw extruders for several years. They will make every effort to meet the needs of users.
Nanjing JIEYA attend Chinaplas 2021 held in Shenzhen. We sincerely welcome your visiting.
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Time: April 13-16, 2021
Address: Shenzhen World Exhibition Center
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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
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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.
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.
The drive section of the twin screw extruder consists of 3 parts: motor, clutch, and gearbox.
The reduction and distribution gear unit reduces the motor speed to the screw shaft speed and distributes the input torque to the two output shafts. Clutch is installed between the drive motor and the gearbox drive shaft.
The processing section of the twin screw extruder in SHJ series extruder consists of individual barrel sections which are replaceable. Depending on the process tasks, reserve feed port, liquid injection port or twin screw side feed port is available.
Owing to the modular design of the twin screw extruder screw elements and screw barrels, conveying, plasticizing, homogenizing, pressure build-up and devolatilization zones can be established, depending on the process task.
For product intake and conveying, screw elements are used. The extruder can be fed with powder, pellets, chips, melt, paste, etc.
Plasticizing, mixing and dispersing are done by the twin screw extruder kneading elements. By varying the thickness of the kneading disks and their angle of stagger, their mixing, shearing and dispersing action can be adjusted to the individual requirements.
The screw elements are arranged on screw shafts. The co-rotating and closely intermeshing screw shafts have a sealing profile.
The screw barrels are supported by barrel supports. Axial displacement of the processing section resulting from thermal dilatation is absorbed by these supports.
The discharge section of the twin screw extruder consists of die head and screen changer, which is installed at the end of twin screw extruder discharging direction. There are several types of die heads and screen changers to meet the requirements of different polymers and processing technology.
The extrusion system of a single screw extruder includes a screw, a cylinder, a funnel, a head, and a nozzle. The plastic is plasticized by the extrusion system into a uniform melt and is continuous under the resulting pressure through the screw of the extruder head.
What is the relevant information about single screw extruders?
How to improve the product quality of the single screw extruder?
What role does the heating and cooling system play in the single screw extruder?
Each product type in the production line for single screw extruders has its operating characteristics. Only if you know their operating characteristics can you fully measure the efficiency of the machine.
Slug extruder's one of the guys. Record the operating points of single screw extruders and use single screw extruders correctly and sensibly.
The use of a single screw extruder includes several connections such as machine setup, adjustment, test run, operation, maintenance, and repair. Its use has the common characteristics of general machines, mainly in the drive engine and in the speed reduction device.
The working system of the single screw extruder, however, is the extrusion system, which has unique characteristics. When using the single screw extruder, pay particular attention to its properties.
1. About the extrusion product quality of the single screw extruder:
Injection extruders must conform to the raw material formula and process, the product size must correspond to the extrusion equipment and the raw materials must be sufficiently mixed and plasticized to ensure stable extrusion pressure and product quality.
2. Improve extrusion efficiency:
It is related to the selection of the single screw extruder, the screw structure, and the material properties, which are relative and must be considered comprehensively. Simple method, you can choose a larger extruder, the nozzle is opened into a nozzle and several forms.
The heating and cooling system of the inlet extruder consists of a heating device and a cooling device. It is a necessary condition for the smooth running of the extrusion process. The heater and cooling system shall ensure that the polymer material is melted and plasticized and that the temperature conditions during the molding process meet the process requirement.
The cooling system is generally installed in the cylinder, in the screw, and the bottom of the funnel of the inlet extruder. The cylinder cooling may be water-cooled or air-cooled. In general, small and medium extruder air cooling is used; Large series single screw extruders usually use water cooling or a combination of both. The main use of sludge cooling is a central water cooling system, the purpose of which is to increase the rate of solidification of the material, to stabilize the volume of discharges, and, at the same time, to improve product quality. The cooling system at the bottom of the funnel serves mainly to enhance the conveying effect of solids and to prevent the material particles from sticking due to the increase in temperature, blocking the material opening and impairing the supply. In general, in the case of extruders with screw diameters over 90 mm and fast-running screw extruders, a cooling device shall be installed at the bottom of the funnel.
Nanjing JlEYA has worked for many years to meet every customers’ need for single screw extruder. Just connect them.
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.
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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 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/