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  Nanjing Jieya Extrusion Equipment Co., Ltd. (referred to as "Jieya") was established in 2004. It has the manufacturing capacity of various types of production lines with an annual production and sales of more than 350 sets. Its comprehensive capability ranks in the forefront of the Nanjing twin screw extruders industry. The company focuses on the R&D and manufacturing of various production lines centered on co-rotating twin-screw extruders and single-screw extruders. The product applications cover compounding, modified granulation, polymerization, devolatilization, one-step molding, and recyclable resources, etc.

  Project Director Mr Chen introduced that every industry has competition, but specific to a certain market segment, the competitors involved are different. Traditional physical blending and modification is the largest market for twin-screw extruders, so the competition is the most intense. For Jieya, the bio-degradable plastic market was changed greatly in 2021, and a considerable part of Jieya’s orders in 2021 also came from this market.

  Mr Chen explained that the reason why bio-degradable plastics are singled out from the traditional blending and modification market is that there have been many entrants in this market in the past two years, which has led to the rapid expansion of the market scale. Therefore, from traditional compounding and extrusion to processing bio-degradable plastics, is it necessary to carry out certain technical reserves? Mr Chen said frankly that it depends on how much bio-degradable plastics companies want to achieve. Just like melt blown materials in 2020, some companies have astonishing shipments, and some companies choose to take the quality to a higher level. The bio-degradable material made by special equipment must be of higher quality.

  Around 2010, Jieya began to get involved in bio-degradable-related projects. During this period, we saw the ups and downs of major companies, and also witnessed the gradual growth of some companies from small to large. Most of these surviving companies are in the bio-degradable market. They started foreign trade before they became popular, and some companies even achieved a market share of about 30% in the export of Chinese vest bags.  

   He also talked about some distressing points in the biodegradable market: at present, the Chinese government has not clearly stipulated the definition and criteria of "bio-degradable". For example, some regions regard photo-degradable as a kind of bio-degradable. Many people oppose this. Mr Chen said that at present, most people in the Chinese market think that 'bio-degradable' is compostable and degradable, and garbage must be sorted and recycled before composting is possible.

  However, Mr Chen is still very optimistic about the development of bio-degradable plastics. Bio-degradable must be the general trend of future social development, but the specific direction remains to be verified. Jieya has a layout for the main bio-degradable plastic categories, such as targeting for many PBAT projects launched in China in the past two years, we are actively discussing with customers whether we can directly use the twin-screw extruder in the polymerization stage to directly make modified materials (without extruding PBAT raw materials). Jieya has also followed up on the project of carbon dioxide production of PPC bio-degradable materials and PGA synthesized with glycolide. At present, the bio-degradable plastics market is still developing and improving. What we need to do now is to develop the corresponding twin-screw technology with the industrial chain. Based on the accumulated experience of a large number of practical applications to continuously improve the stability of the equipment.

  Under the big goal of carbon neutrality, some very big changes have taken place in industries such as home appliances and automobiles. The intuitive impact is that Jieya has recently received some projects for recycling, dismantling, and regranulating waste household appliances, as well as the crushing, recycling, and regranulation of some new energy battery shells, which is also one of the important markets for Jieya in 2021. Mr Chen said that these manufacturers have multiple production lines and large projects, but they are usually new entrants, and usually require suppliers to provide them with whole-plant project planning, so they put forward higher requirements for suppliers' project experience and service capabilities.

  Fluorochemicals, another key application area for which Jieya is recognized. Fluoroplastics are also known as "plastic kings". Their corrosion resistance, solvent resistance, weather resistance and temperature resistance are relatively good, so they are often included in the field of special engineering plastics. The most well-known is the PVDF used with lithium battery binder. In 2021, Jieya also undertook some projects in this field.

   Mr Chen believes that the Chinese market is developing very fast, and twin-screw extruder enterprises must keep abreast of customer needs in order to gain a foothold in the market. Therefore, Jieya is also seeking new development in the upstream links. For example, the twin-screw devolatilization extrusion unit developed to meet the growing demand of downstream customers for products with low VOC and low residue; as well as corrosion resistance and wear resistance under high temperature conditions. The extrusion unit meets the production needs of special products under severe working conditions.

  The success of Nanjing Jieya in the market is inseparable from the technical advantages of its twin-screw extruder equipment: its core components are all self produced, including high-torque gearboxes, extruder barrels, extruder screw elements, screen changer, die, etc. The product quality is stable and controllable, which can meet the personalized customization needs of customers, and the delivery time is flexible. In addition, Jieya stable team has also played a huge advantage. It is said that its sales, technology, management, and after-sales teams have an average of more than 10 years of experience in the industry. They have rich industry experience and are relatively clear about the pain points of various market segments. Provide complete personalized solutions, and can also undertake large and complex complete system projects.

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

 

Structural principles

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.

 

Temperature Principle

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.

 

Speed reduction principle

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.

A twin screw extruder is composed of several parts such as a transmission device, feeding device, barrel, and screw, etc. The role of each part is similar to that of the single screw extruder. So what are the main differences between the twin screw extruder and single screw extruder? The following is the detailed introduction

 

Here is the content list:

l Cross sectional profile

l The way of material transfer

l The material flow velocity field

 

Cross sectional profile

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.

 

The way of material transfer

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 material flow velocity field

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.

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:

• Daily maintenance.

• Regular maintenance.

 

Daily maintenance.

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.

 

Regular maintenance.

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.

A single-screw extruder consists of an Archimedes screw rotating in a heated barrel. It is widely used because of its simple structure, easy manufacturing, high processing efficiency, and low price, and is the most technically mature and used type of extruder at present. The following is a detailed introduction to single-screw extruders.

 

Here is the content list:

• The design concept of a single-screw extruder

• Single-screw extruder features

• Uses of single screw extruder

 

The design concept of a single-screw extruder

(1) Single-screw extruders are high-speed, high-output extrusions based on high quality, and the design concept of low-temperature plasticization ensures the extrusion of high-quality products. Two-step overall design to strengthen the plasticizing function and ensure the adjustment of high-performance extrusion.

(2) A special barrier of the single-screw extruder, integrated mixing design to ensure material mixing effect and high torque output, extra-large thrust bearing.

(3) The gears and shafts of a single screw extruder are high-strength alloy steel, carburized, ground teeth treatment, high hardness, high finish, and ultra-low noise. PLC intelligent control, the linkage between main and auxiliary machines is possible.

(4) Single screw extruder easy to monitor human-machine interface, easy to understand the processing and machine status, and the control method (temperature control instrument) can be changed as needed.

(5) The material of the single screw extruder is 38CrMoAL/A nitride treatment, which is wear-resistant. It has a combination of air-cooled and water-cooled cooling for strict temperature precision control, and the unique air inlet design makes it a perfect water-cooling device.

(6）Single screw extruder with grooved surface feeding bottom sleeve of screw barrel has enhanced feeding function, which provides a guarantee for high speed and high output extrusion.

 

Single-screw extruder features

1. Hard gearbox, AC or DC stepless drive speed regulation.

2. New screw structure, melt and mix uniformly to ensure low melt temperature and high output

3. Screw barrel material adopts nitride steel 38CrMoAIA nitride treatment, and the surface alloy treatment has higher hardness.

4. Cast copper, cast aluminum heater, air-cooled and water-cooled according to requirements.

5. Advanced electrical control system of single screw

 

Uses of single screw extruder

Pipe extrusion of single-screw extruder: it is suitable for PP-R pipe, PE gas pipe, PEX cross-linked pipe, aluminum-plastic composite pipe, ABS pipe, PVC pipe, HDPE silicon core pipe, and various co-extruded composite pipes.

Sheet and plate extrusion: applicable to PVC, PET, PS, PP, PC, and other profiles and plates extrusion. Extrusion of various other plastics such as silk, rod, etc.

Profile extrusion: adjusting the extruder speed and changing the structure of the extrusion screw can be applied to the production of various plastic profiles such as PVC, polyolefin, etc. Modified pelletizing: It is suitable for blending, modifying, and enhancing pelletizing of various plastics.

 

Nanjing JlEYA is a leading extruder manufacturer specializing in a twin-screw extruder, micro twin-screw extruder, plastic extruder, and parallel twin-screw extruder, which are widely used in compounding, modification, polymerization, devolatilization, reaction, recycling, and other fields. After 17 years of development for many years, now we have a 20,000 square meters plant, 300+ sets of annual sales, and export to more than 60 countries.

The twin screw extruder has the basic principles of single-screw extruder: solid conveying, melt pressurization and pumping, mixing and stripping and evaporation, but it is not limited to this. The development of twin screw extrusion theory is relatively late, coupled with its wide variety, messy screw shape, and messy extrusion process, which brings many difficulties to the research. And the following words will give you a brief introduction about the information of the twin screw extruder.

What is the future research direction of twin screw extruder?

What is the basic principle of a twin screw extruder?

What is the difference between a twin screw extruder and a traditional extruder?

What is the future research direction of twin screw extruder?

1. Established the physical model and mathematical model of the twin screw extruder to guide the design of the twin screw extruder and the optimization of the extrusion process.

2. It is necessary to understand the relationship between the true state change, the mixing form, the whole process of the structure change and the later mixing and characteristics of two or more polymers and materials during the entire extrusion process.

3. As a twin screw extruder, it establishes the internal connection between the entire reaction process, speed and characteristics of the extrusion reaction molding and the screw structure and operating conditions. It can be extruded through reaction molding.

What is the basic principle of a twin screw extruder?

The twin screw extruder has the basic principles of single-screw extruder: solid conveying, melt pressurization and pumping, mixing and stripping and evaporation, but it is not limited to this. The development of twin screw extrusion theory is relatively late, coupled with its wide variety, messy screw shape, and messy extrusion process, which brings many difficulties to the research.

Generally speaking, the research of twin-screw extrusion theory is still in the development link, which is called "technology more than science". From the perspective of the entire extrusion process of a twin screw extruder, there are about three parts: the polymer's physical state change rule during the extrusion process, the basic principle of conveying, the conveying of solid melt, the exhaust phase and the law, and the establishment of mathematics The physical model is used to guide the planning of the twin screw extruder and the optimization of the extrusion system process.

What is the difference between a twin screw extruder and a traditional extruder?

The traditional extrusion molding process requires rotating a giant screw in the barrel. When using twin screw extrusion, the two screws mesh with each other and rotate together during the extrusion operation. They are installed in the housing on the spline shaft of the barrel. The twin screw extruder can simultaneously ensure food molding, heating, cooling, compression, mixing, pumping and even transportation.

At present, twin screw extruder has become the most common extruder with the largest variety and specifications in the world. Nanjing JlEYA has committed to fulfilling all the requirements of twin screw extruders. And it welcomes global customers to purchase.

DRIVE SECTION
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.
PROCESSING SECTION
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.
EXTRUSION PART
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.

2022 Chinese Mid-autumn festival is coming.

Jieya team wish you happy mid-autumn festival and enjoy your holiday!!

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