In plastic extrusion molding equipment, the plastic extruder is usually called the main machine, while its subsequent equipment plastic extrusion molding machine is called the auxiliary machine. Plastic extruders can produce a variety of plastic products. Therefore, the plastic extrusion molding machine is one of the widely used machines in the plastics processing industry, both now and in the future. So what are the characteristics of plastic extruders? The following is a detailed introduction.
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Modularity and specialization
High efficiency and multi-functionalization
Enlargement and precision
Intelligent and networked
The modular production of plastic extruders can adapt to the special requirements of different users, shorten the research and development cycle of new products, and strive for a larger market share; while specialized production can arrange the production of each system module component of extrusion molding equipment at a fixed point or even for global procurement, which is very beneficial to ensure the quality of the whole period, reduce costs and accelerate the capital turnover.
The high efficiency of plastic extruders is mainly reflected in the high output, low energy consumption, and low manufacturing cost. In terms of function, the screw plastic extruder has been used not only for extrusion molding and mixing processing of polymer materials but its use has been broadened to food, feed, electrode, explosives, building materials, packaging, pulp, ceramics, and other fields.
Achieving the large-scale plastic extruder can reduce the production cost, which is a more obvious advantage in the large twin-screw plastic pelletizing set, film blowing set, pipe extrusion set, etc. National key construction services required for major technical equipment, large-scale ethylene project supporting one of the three key equipment of large extrusion pelletizing unit long-term dependence on imports, so we must accelerate the localization process to meet the development needs of the petrochemical industry.
Plastic extruders in developed countries have generally used modern electronic and computer control technology, the entire extrusion process parameters such as melt pressure and temperature, the temperature of each section of the body, the main screw and feeding screw speed, feeding volume, the ratio of various raw materials, motor current and voltage and other parameters for online detection, and the use of microcomputer closed-loop control. This is extremely beneficial to ensure the stability of process conditions and improve the precision of products.
If you need to buy a plastic 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, 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 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.
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Twin-screw extruders have barrels with an extension range of 4 and 6D, allowing for precise process design to meet specific customer requirements. All barrels allow for precise temperature control. Cooling is achieved by cooling water injection and high-performance electric heating rods for direct and fast heating. The auxiliary equipment of the twin-screw extruder consists of a straightening device, a preheating device, and a cooling and heating device. The following is a detailed description of the auxiliary equipment.
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l Straightening device
l Preheating device
l Cooling device
One of the most common types of plastic extrusion rejects is eccentricity, and bending of the wire core in various patterns is one of the most important causes of insulation eccentricity. In sheath extrusion, scratches on the sheath surface are also often caused by the bending of the cable core. Therefore, a variety of extrusion units in the straightening device is essential. The main types of straightening devices are roller type (divided into horizontal and vertical type); pulley type (divided into single pulley and pulley group); stranded pulley type, which plays a variety of roles such as dragging, straightening, and stabilizing tension; pressure pulley type (divided into horizontal and vertical type), etc.
Cable core preheating is necessary for both insulation extrusion and sheath extrusion. For the insulation layer, especially the thin layer of insulation, the existence of pores should not be allowed, the core can be completely removed from the surface of the water, oil, and dirt through high temperature preheating before extrusion. For the sheath extrusion, the main role is to dry the cable core, to prevent the role of moisture (or moisture around the bedding layer) to make the sheath in the possibility of porosity. Preheating can also prevent the plastic from being extruded due to sudden cooling and residual internal pressure. In the process of extruding plastic, preheating can eliminate the cold line into the high-temperature heat, in contact with the plastic at the mouth of the die to form a disparity in temperature, to avoid fluctuations in plastic temperature and lead to fluctuations in extrusion pressure, to stabilize the amount of extrusion and ensure the quality of extrusion. Extrusion unit is used in the electric heating core preheating device, requires sufficient capacity, and ensures rapid temperature rise, so that the core preheating and cable core drying efficiency. The preheating temperature is restricted by the speed of wire release, generally similar to the temperature of the head.
The formed plastic extrusion layer after leaving the head should be immediately cooled and shaped, otherwise, deformation will occur under the action of gravity. The way of cooling usually uses water cooling, and according to the water temperature is different, divided into rapid cooling and slow cooling. Rapid cooling is the direct cooling of cold water, rapid cooling of plastic extrusion layer sizing is beneficial, but for crystalline polymers, due to sudden heat cooling, easy to internal residual stress in the extrusion layer organization, resulting in the use of the process of cracking, general PVC plastic layer using rapid cooling. Slow cooling is to reduce the internal stress of the product, in the cooling water tank placed in sections of different temperatures of water, so that the product gradually cool down and set, PE, PP extrusion on the use of slow cooling, that is, after hot water, warm water, cold water three cooling.
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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.
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 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?
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
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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.
Malfunctions that are caused by inadequate or improper maintenance can result in high repair costs and unnecessarily long gearbox down times. Regular servicing and inspection work are therefore imperative!
All servicing and repair work is only allowed to be performed with the gearbox stationary and by trained,authorized and appropriately instructed personnel.
Refilling lubrication oil
The oil level is to be checked regularly.It must never be below the bottom mark. In the case that the oil level drops below the minimum,it is imperative that the lubricant is topped up. The oil is only allowed to be topped up with the drive units shut down. A funnel with a filter is to be used for toppcng up (filter mesh 40um). The gearbox is always to be filled with the same type of oil as used previously It is not allowed to mix different oils or oils from different manufacturers.
The effectiveness of the oil reduces with increasing use due to soiling (foreign bodies and water) and chemical changes(ageing products). When the soiling and/or ageing is/are excessive, it is necessary to change the oil. Regular oil analyses provide information on the effectiveness of the gearbox oils. For larger quantities of oil it is recommended to make oil changes dependent on the results of an oil analysis.A missed oil change increases the risk of damage and can result in premature failure of the gearbox.
The first oil change should be made at approx.2500 perating hours.Subsequent oil changes depend on the state of the oil and are to be performed every 4,000 to 6,000 operating hours, however at the latest after one year.
The gear box is the core part of the twin screw extruders, we shall pay attention to its maintenance for long servicelife.