The special refining effect and excellent performance of the single screw extruder have been proved in practice. Practice has proved that the reciprocating single-screw mixing extruder is a new type of plastic extrusion equipment. The emergence of single screw extruder provides a high-performance plastic processing equipment for the majority of users. Made a huge contribution to the development of the plastics industry.
What is the function of the single screw extruder operation screen?
What is the significance of the emergence of a single screw extruder?
What are the application fields of single screw extruder?
The operating panel is installed above the single screw extruder and can be rotated within 60 degrees for easy operation. There is a power indicator and emergency stop button on the right side of the touch screen. In an emergency, press the emergency stop button to stop immediately, which is used to protect the safety of the operator and the single screw extruder. The data recording, parameter setting, operation control and other operations of the entire instrument are all completed in this operation screen.
In the process of polymer processing, in order to give the polymer certain processing characteristics or to give the product specific use performance, it is often necessary to blend different polymers or blend the polymer with various additives and pigments. The single-screw extruder has the characteristics of uniform shearing, high dispersion, high filling, and stretching of the melt. And it combines the advantages of single and twin screw extruders. The unique working principle, coupled with a complete set of threaded components and supporting equipment, makes it more widely used. On a single screw extruder, it can achieve mixing, Mixing, plasticizing, dispersing, shearing, stretching, degassing, and granulation make the interface area of the melt flow in the machine far larger than the general shear flow.
The reciprocating single-screw mixing extruder is a new type of plastic mixing processing equipment, which is widely used in the filling, blending, modification, crosslinking, grafting, color masterbatch, functional masterbatch, and resistance of various plastics. Production of fuel masterbatch, conductive material, degradable masterbatch, reinforcement, toughening and other special plastic materials.
Blending different types of polymers to obtain brand new polymer alloys with specific uses.
Various mineral fillers are added to the polymer melt to make high-filling materials with excellent performance and low price.
Production of various glass fiber reinforced and flame retardant products, with the addition of glass fiber up to 50%.
It is suitable for the production of various cable sheathing materials, insulating materials, cross-linking materials, semiconductors, shielding materials, and conductive materials.
Production of thermoplastic elastomers and hot melt adhesives.
The single screw extruder is increasingly used in industrial production.Nanjing JlEYA has committed itself to offering the best-suited single screw extruders at a reasonable price, and all that is necessary to meet the needs of the customer.
The single screw extruder is a special reduction power device designed for plastic and rubber single screw extruder equipment. The reducer is matched with the motor. The gear parts are made of high-strength alloy steel. The gears are processed by carburizing, quenching, and high-precision gear grinding. The gear accuracy is level 6, and the tooth surface hardness is HRC58-62.
What is the principle of single screw extruder?
What is the current industry development of single screw extruder?
What should I pay attention to when using single screw extruder?
The single screw extruder is generally divided into three sections in effective length. The effective length of the three sections is determined according to the diameter of the screw and the pitch and depth of the screw, which are generally divided into one-third of each; the last thread of the single screw extruder has been called the conveying section. It is required that it cannot be plasticized, but it must be preheated and compressed;
The second section of the single screw extruder is called the compression section. At this time, the volume of the screw groove gradually decreases, and the temperature must reach the degree of plasticization of the material. The compression produced here is from the conveying section three, and here it is compressed to one. Some machines also have Change, the plasticized material enters the third stage;
The third section of the single screw extruder is the metering section, where the material maintains the plasticizing temperature to supply the machine head, which is generally slightly higher than the plasticizing temperature.
In single screw extruder equipment, the plastic extruder is normally referred to as the main machine and the following equipment, the plastic extruder, is referred to as the auxiliary machine. After more than 100 years of development, the plastic extruder has been derived from the original single-screw extruder, a variety of models such as double-screw, multi-screw and even non-screw models have been derived. The plastic extruder (host) can be used with different plastic moulding machines such as tube, foil, holding material, monofilament, flat wire, strapping, extruding network, plate material, profile material, pelleting, cable coating, etc. are used. Suitable for different plastic extrusion production lines for the production of different plastic products. Therefore, plastic extrusion machines are today and in the future one of the most common models in the plastics processing industry.
What should I pay attention to when using single screw extruder?
(1) The material convey way of the single screw extruder mainly relies on friction, which limits its feeding performance. And it is difficult to add the powder, paste, glass fiber and inorganic fillers, so pay attention to the material used.
(2) When the pressure of the single screw extruder head is high, the reverse flow will increase and the productivity will decrease. Therefore, always pay attention to the pressure of the equipment.
(3) The surface renewal effect of the single screw extruder material in the exhaust zone is small, so the exhaust effect is poor.
(4) single screw extruder is not suitable for certain processes, such as polymer coloring, thermosetting powder processing, etc.
The single screw extruder has achieved an irreplaceable position in industrial production. Nanjing JlEYA is committed to providing various bending and rolling machines of high quality for all customers from all over the world.
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 basic mechanism of the twin screw extrusion process is simply that a screw rotates in the barrel and pushes the plastic forward. The screw structure is a bevel or ramp wrapped around a central layer, the purpose of which is to increase the pressure to overcome the higher resistance. What do I need to pay attention to when using a twin screw extruder? The following is a detailed description.
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.
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.
underwater pelletizing machine is similar to airflow granulator and water jet granulator. The equipment part mainly covers: plastic granulator, single and twin screw plastic extruder, plastic film blowing machine, bag making machine, printing machine, coating machine, Adhesive tape machine, tape slitting machine, slitting machine, strapping machine.
What is the problem of uneven pelletizing by the underwater pelletizing machine?
What is the workflow of the underwater pelletizing machine?
What is the technological advantages of the underwater pelletizing machine?
1. underwater pelletizing machine, the machine head is not evenly heated, and the machine head temperature is stable before starting up;
2. The cooling water of the underwater pelletizing machine is boiled prematurely, and the water should be boiled when the machine head starts to discharge;
3. It is also possible that there is a problem with the hot runner design of the machine head, which is caused by uneven pressure.
Before being made into final products, most polymers must be blended and then pelletized to become marketable raw materials. The power required by the underwater pelletizing machine is directly proportional to the extrusion volume and exponentially related to the size of the filter screen. There are many different types of pelletizer designs, but all pelletizers have some common places, and they can be divided into two categories: cold pelletizing system and die face hot pelletizing system. The main difference between the two categories is the time arrangement of the pelletizing process. The cold pelletizing system cuts pellets from the solidified polymer at the end of the process; while in the die-face hot pelletizing system, pellets are cut when the molten polymer emerges from the die, and pellets are processed downstream cool down.
The underwater pelletizing machine treated by standard process has the following significant advantages:
The appearance standard of the products produced by the underwater pelletizing machine is exquisite and bright;
2. The hardness of the wear layer in contact with the material by the underwater pelletizing machine can reach HV 600-800, and the local hardness can reach HV900-1100. The hardness is increased to 2-4 times the original hardness. Compared with the non-standard machine without heat treatment, it is resistant to The wear performance is increased by 3-5 times;
3. The products of the underwater pelletizing machine are not deformed after long-term use, effectively avoiding the screw breaking due to the excessive wear of the barrel, and the stable service life is 2-3 times that of the traditional machine, which greatly reduces the investor's investment in replacement parts;
4. The wear-resistant layer of the barrel screw produced by the underwater pelletizing machine has high hardness, while the base material still retains good toughness and processing performance;
5. The service life of the screw of the underwater pelletizing machine has increased from the hundred-ton level of the ordinary plastic pelletizing machine to the thousand-ton level.
Nanjing JlEYA has focused on the production and development of underwater pelletizing machines for several years, and they have always put the needs of customers as their top priority. Here, you can choose the underwater pelletizing machine that suits your need.
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.
Plastic extruders can be divided into single-screw extruders, twin-screw extruders, and multi-screw extruders according to their number of screws. The following are the details of the types of plastic extruders.
Here is the content list:
Classification of plastic extruders
Classification of plastic extruders
1, According to the number of screws, divided into single-screw extruders, twin-screw extruders, and multi-screw extruders.
2, According to the presence or absence of a screw in the extruder, divided into screw extruders and plunger extruders.
3, According to the running speed of the screw to divide:
Ordinary extruder: speed below 100r/min.
High-speed extruder: speed of 100 to 300r/min.
Super high-speed extruder: the speed is 300~l500r/min.
4, According to the extruder assembly structure classification: there are integral extruders and separate extruders.
5, According to the spatial position of the screw in the extruder, can be divided into the horizontal extruder and vertical extruder.
6, According to whether the extruder is in the process of exhaust and can be divided into exhaust type extruder and non-exhaust type extruder
The single-screw extruder occupies an important position both as a plasticizing and pelletizing machine and as a molding machine, and in recent years, the single-screw extruder has developed greatly. Single-screw extruders were the first extruders to gain widespread application in the plastic processing and molding field due to their simple structure and high processing efficiency. Similarly, to meet different processing needs, various equipment manufacturers have explored various screw and barrel structures. The single-screw extruder has evolved from the basic pure screw structure to various structures such as damping screw block, exhaust extrusion, slotted screw barrel, pinned barrel, building block structure, etc., thus enabling the single-screw extruder to have a wider range of molding.
Due to the small footprint of single-screw extruders, they are almost the only equipment used in the compounding and blown film fields. Single-screw extruder technology has become an important part of the extrusion process market that cannot be ignored.
The twin-screw extruder has less heat generated by friction, more uniform shearing of the material, larger conveying capacity of the screw, more stable extrusion volume, long stay of the material in the barrel, and uniform mixing.
The twin-screw extruder has good feeding characteristics, is suitable for powder processing, and has better mixing, exhaust, reaction, and self-cleaning functions than the single-screw extruder, characterized by the processing of plastics with poor thermal stability and co-mingled materials show its superiority. Based on the twin-screw extruder, the multi-screw extruder was developed for easier processing of co-blends with poor thermal stability.
If you want to buy an extruder, you can consider our cost-effective products. Nanjing JlEYA is the leading manufacturer extruder manufacturer specializing in a twin-screw extruder, mini twin screw extruder, plastic extruder, and parallel twin-screw extruder in China, which is widely used in compounding, modification, polymerization, after 17 years of development, now we have 20,000 square meters workshop with annual sales over 300+ sets, export over 60 countries.