The plastic extruder is a common plastic machinery equipment, in the process of the daily operation of the extruder, the extruder will have a variety of failures, affecting the normal production of plastic machinery, the following we will analyze the extruder failure.
Here is the content list:
Unstable host current
The main motor can not start
The head is not discharged smoothly or blocked
The main electric starting current is too high
The main motor makes an abnormal sound
1. Production reasons.
(1) Uneven feeding.
(2) The main motor bearing of the plastic extruder is damaged or poorly lubricated.
(3) A section of the heater is out of order and does not heat up.
(4) The screw adjustment pad is not correct, or the phase is not correct, and the component interferes.
2. Treatment methods.
(1) Check the feeder, troubleshooting.
(2) Overhaul the main motor of the plastic extruder, replace the bearings if necessary.
(3) Check whether each heater is working properly, replace the heater if necessary.
(4) Check the adjustment pad, pull out the screw to check whether there is interference with the screw.
(1) There is a mistake in the start-up procedure of the plastic extruder.
(2) The main motor thread has a problem, whether the fuse is burned ring.
(3) The main motor-related chain device to function
2. Treatment methods.
(1) Check the program, reboot the machine in the correct boot sequence.
(2) Check the main motor circuit.
(3) Check whether the lube oil pump of the plastic extruder is started and check the status of the chain device associated with the main motor. The oil pump is not on and the motor cannot be turned on.
(4) The inverter induction power has not been discharged. Turn off the main power and wait for 5 minutes before starting again.
(5) Check whether the emergency button is reset.
(1) A section of the heater does not work, and the material is not plasticized well.
(2) The operating temperature setting is low, or the molecular weight distribution of plastic is wide and unstable.
(3) There may be foreign substances that do not melt easily.
2. Treatment methods.
(1) Check the heater of the plastic extruder and replace it if necessary.
(2) Verify the set temperature of each section, and if necessary, consult with the technician to increase the temperature setting.
(3) Clean and check the extrusion system and the head.
(1) Insufficient heating time and high torque.
(2) A section of the heater does not work.
2. Treatment methods.
(1) Apply hand pan machine when starting, if not easy, extend the heating time or check whether each section heater is working properly.
1. Produced by.
(1) The main motor bearing of the plastic extruder is damaged.
(2) The main motor silicon controlled rectifier line in silicon controlled damage.
2. Treatment methods.
(1) Replace the main motor bearings.
(2) Check the silicon-controlled rectifier circuit, if necessary, replace the silicon-controlled components.
Our company's website is https://www.njjyextrusion.com/. If you still have questions, you can contact us on the official website.
Nanjing JIEYA hereby sincerely invited you to attend 2021 China (Hainan) Degradation Exhibition.
Our booth no.: B06
Time: June 23-25
Add: Hainan International Convention and Exhibition Center
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As common extruder equipment used in the plastic processing industry, single screw extruder is mainly used for extruding soft and hard PVC, polyethylene, and other thermoplastics, which can process many kinds of plastic products, such as blown film, extruded pipe, pressboard, drawn ribbon, etc. It can also be used for melt pelletizing. The plastic extruder has advanced design, high quality, good plasticization, low energy consumption, involute gear transmission, low noise, smooth operation, high load capacity, and long life. To have a long service life of the machine, maintenance measures are indispensable, the following is a detailed description of the single-screw extruder maintenance measures.
Here is the content list:
1. Because the electrical control system of single-screw extruder has high requirements for ambient temperature and dustproof, the electrical system should be separated from the production site, and install ventilation or ventilation fan, it is recommended that the electrical control cabinet in a simple room, keep the room clean, ventilation, so that the indoor temperature is not higher than 40 ℃.
2. Single-screw extruderis not allowed to run empty, so as not to roll the screw and machine simple hair. Host start idling is not allowed to exceed 100r / min; start the host first low speed, after starting the host to check for abnormal noises and then slowly increase the host speed to within the allowable range of the process (can be adjusted to the best state is good). When the new machine is breaking in, the current load should be at 60-70%, and the current in normal use should preferably not exceed 90%. Note: If an abnormal sound occurs when the extruder is running, it should be stopped immediately for inspection or repair.
3. Turn on the oil pump first and turn off the oil pump after shutting down the machine; keep the water pump working during the whole production process and do not stop the pump to avoid the barrel temperature rising and causing the material in the barrel to decompose and carbonize; the asbestos wind cover of the main motor fan needs to be cleaned often to avoid the dust sticking too much to block the wind cover and cause the motor to overheat and trip due to insufficient heat dissipation.
4. Clean up the dust and dirt, tools, and debris on the surface of the unit in time.
1.Regularly check the screws and other fasteners on the surface of the single-screw extruder unit for looseness and timely and proper tightening. The lubricant level of the transmission box should be added or replaced promptly (the dirt at the bottom of the oil tank should be cleaned regularly). For new machines generally, 3 months to replace the oil, after that every six months to a year. The oil filter and oil suction pipe should be cleaned regularly (once a month).
2. Single screw extruder gearbox maintenance and general standard reducer are the same. The main thing is to check the wear and failure of gears and bearings.
3, When reinstallation please note that A, B two screws must be in the original position, can not be replaced! After the installation of the new combination of the screw on the machine, you must first use the hand pan car, such as normal rotation before the low-speed start. Screw or barrel for a long time without use, there should be anti-rust and anti-fouling measures, the screw should be placed hanging. If the threaded block is with fire, the flame should be moved left and right, while burning to clean up, and can not burn too much (blue ringers red), not to mention the thread block into the water.
4. Regularly calibrate the temperature control instrument to check the correctness of its adjustment and the sensitivity of its control.
5. In the barrel with a cooling water tank, must be used distilled water to prevent the formation of scale blocking the cooling water channel in the barrel, resulting in temperature failure. Pay attention to the appropriate amount of water in use to prevent scaling. If the blockage should be changed down the cylinder specific maintenance, no blockage and the water output is small indicates that there is scale, the tank water should be changed to dilute hydrochloric acid swishing cycle, clear scale to normal and then change the distilled water. General water in the tank is used to cool the barrel, and the natural water we pass is used to cool the tank. Regularly check the water quality of the cooling water tank, if there is turbidity, should be replaced promptly.
6.Check whether the solenoid valve is working properly, the coil has not burned out if there is a timely replacement.
7. The temperature does not rise to quite the temperature continues to rise and fall may exist for the following reasons: whether the day electric couples loose fall; heater relay is working properly; solenoid valve is working properly, timely replacement of deformation of the heater, and tighten the screws.
8. Timely clean up the dirt in the vacuum tank, and the material in the exhaust chamber so that the pipeline is smooth. Vacuum pump seals need to be replaced promptly if there is wear and tear regular inspection, the output shaft jumping is bearing damage and shaft fracture must be opened and replaced, such as the gearbox two output shaft bearing position wear is too serious, the box must be replaced to avoid greater loss of failure.
9, To drive the screw rotation of the DC motor to focus on checking the brush wear and contact, the insulation resistance value of the motor whether in the specified value should also be measured frequently. In addition, check the connection line and other components that are rusted, and the use of protective measures.
10. When the single-screw extruder needs to stop using for a long time, should be in the screw, Jane, the head, and other working surfaces coated with anti-rust grease. The small screw should be suspended in the air or placed in a special wooden box, and a wooden block pad flat, so as not to deform the screw or bruise.
11. Single-screw extruder attached to the cooling water pipe wall is prone to scale external corrosion and rust. Maintenance should be carefully checked, too much scale will block the pipeline, can not achieve the cooling effect, rust will be serious leaks, so maintenance must take descaling and anti-corrosion cooling measures.
12. Designate a person responsible for the maintenance of equipment. And each maintenance and repair detailed record is included in the plant equipment management files.
If you still have questions, you can consult our company, we are happy to answer for you. The company insists on the purpose of "quality first, customer first", and warmly welcomes new and old customers to cooperate with us.
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 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/
Twin screw extruder is developed based on the single screw extruder, which has been widely used in the molding process of extruded products because of its good feeding performance, mixing and plasticizing performance, exhaust performance, and extrusion stability. So what are the advantages of a twin screw extruder? The following is a detailed introduction.
Here is the content list:
l Wear and tear
l Reduce production costs
l Increase output
l Improve labor efficiency
l High torque and high speed
Wear and tear
Since twin screw extruders are easy to open, the degree of wear of threaded elements and barrel bushings can be detected at any time, so that effective repair or replacement can be carried out. It is not necessary to find out only when there is a problem with the extruded product, which causes unnecessary waste.
Reduce production costs
When producing masterbatches on twin screw extruders, it's usually necessary to alter colors, and if a product amendment is critical, to open the open process space within several minutes, in addition to analyzing the mixing process by looking at the melt profile on the entire screw. The current common twin screw extruder needs to be cleared with a large amount of clearing material when changing colors, which is time consuming, power consuming, and a waste of raw material. The split twin screw extruder can solve this problem. When changing the color, it only takes a few minutes to quickly open the barrel for manual cleaning, so that no or less cleaning material can be used, saving costs.
Twin screw snack extruders use side feeding technology to improve the integrity of the material and greatly increase production. The position and shape of the feed opening also have a great influence on feeding efficiency. With the same parameters, the output increases with an increase in the feed area. A rectangular cross section has a higher feed efficiency than a circular cross section for the same inlet area. The use of side by side twin screw feeds is also based on this consideration.
Improve labor efficiency
During equipment maintenance, ordinary twin screw extruders often have to remove the heating and cooling system before the screw can be withdrawn as a whole. In contrast, the split twin screw does not need to be opened by loosening a few bolts and turning the worm gearbox handle device to lift the upper half of the barrel, and then the entire barrel can be repaired. This shortens the maintenance time and reduces the labor intensity.
High torque and high speed
At present, the event trend of twin screw extruders within the world is to develop within the direction of high torsion, high speed, and low energy consumption, and also the impact of high speed is high productivity. The split twin screw extruder belongs to the current class, and its speed will reach and five hundred revolutions per minute. Therefore, its distinctive benefits in process high viscousness and warmth sensitive materials.
In the high speed, high torque core technology, asymmetric and symmetric high torque gearbox currently only Germany and Japan related manufacturers master the core technology, its speed can reach up to 1800 rpm or more, and domestic also master this core technology, such as Nanjing JlEYA extrusion company, is also currently one of the main choices of domestic high end material processing manufacturers, belongs to the domestic independent innovation national encouragement projects.
If you want to buy twin screw extruders, you can consider our cost effective products. We insist on the tenet of "quality first, customer first" and warmly welcome new and old customers to cooperate with us.
The company focuses on twin screw extruders, micro twin screw extruders, plastic extruders, parallel twin screw extruders, and other research and development and manufacturing as the core of the isotropic rotary twin screw mixing and extruding machine, the application range covers the mixing and modification of granulation, polymerization, deswelling, step molding, recycling, and other fields.
Nanjing JIEYA attend Chinaplas 2021 held in Shenzhen. We sincerely welcome your visiting.
Our booth no.: 7Q25
Time: April 13-16, 2021
Address: Shenzhen World Exhibition Center
Look forward to meet you at there.
Jieya team wish you have a nice holiday :)
(Nanjing Jieya is a professional manufacturer of twin screw compounding extruders with 20+ years experience and competitive price. We look forward to receive your inquiry.)