parallel co-rotating twin screw extruder- China Factory Suppliers Manufacturers

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.

 

Here is the content list:

l Straightening device

l Preheating device

l Cooling device

 

Straightening 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.

 

Preheating device

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.

 

Cooling device

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.

 

If you are engaged in a twin-screw extruder-related industry, you can consider our cost-effective products.

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.

The single-screw extruder has a simple design and a low price, so it is widespread and demand on the market was high.

• What are the application areas and benefits of single-screw extruders?

• What is the development history of the single-screw extruder?

• What are the main technical parameters of the single-screw extruder?

What are the application areas and benefits of single-screw extruders?

The single-screw extruder is mainly used for extruding soft and hard polyvinyl chloride, polyethylene, and other thermoplastic. It can process a variety of plastic products such as films, tubes, plates, tapes, etc., can also be used for granulation.

The single-screw extruder is characterized by advanced design, high quality, good plasticization, and low energy consumption. It uses an evolutionary drive that is characterized by low noise development, stable operation, high load capacity, and long service life.

What is the development history of the single-screw extruder?

The single-screw extruder is one of the most important devices for the processing of plastic molding parts. It uses external energy transfer and heat transfer of external heating elements to carry out the transport of plastics solids, compaction, melting, shielding, and extrusion forms.

Since the birth of the snail extruder, it has evolved from an ordinary snail extruder to a new type of snail extruder after almost a hundred years of development. Although there are many types of new single-screw extruders, the extrusion machine is the same.

The extrusion process of the traditional snail extruder is realized by heating outside the cylinder, solid and cylinder, snail friction, and melting shear force.

"friction coefficient" and "friction force", "viscosity" and "shear tension" are the main factors influencing the performance of conventional screw extruders. The extrusion process from the machine is unstable and difficult to control, especially for some heat-sensitive plastics with poor thermal stability and high viscosity.

What are the main technical parameters of the single-screw extruder?

1. Screw diameter: refers to the diameter of the outer circle of the screw, marked with D, and the unit is millimeter (mm).

2. Proportion of screw length to diameter: refers to the ratio of the length L of the working part of the screw (the length of the threaded part, i.e. the length from the center line of the feed opening to the end of the screw) and the screw diameter D, expressed by L/D.

3. Snail speed range: refers to the highest speed of the snail up to the lowest speed of the snail; n is used to represent the speed of the snail, and the unit is revolutions per minute (U/min).

4. The power of the main screw drive engine: expressed by P, the unit is kilowatt (kW).

5. Heating performance of the extruder cylinder: expressed by E is the unit kilowatt (kV).

6. The output capacity of the extruder: expressed by Q, the unit is kilogram per hour (kg/h).

7. The height of the extruder rim: refers to the distance from the center line of the screw to the ground, expressed by H, and the unit is millimeters (mm).

8. Extruder outer dimensions: refers to total length (x) total width (x) total height expressed by L x B x H, and the unit is millimeters or meters (m m or m)

9. Extruder quality: expressed in W, the unit is kilogram or tonne (kg or t).

We can see the huge role that single-screw extruders play in the production industry, and they have become indispensable components. And Nanjing JlEYA a Chinese pioneer in single-screw extruder production,has committed to providing the most suitable single-screw extruder at a reasonable price, and whatever it takes to satisfy the customer’s needs.

The high efficiency of the single-screw extruderis mainly reflected in high output, low energy consumption, and low manufacturing cost. In terms of function, the 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, building materials, packaging, ceramics, and other fields. So how to operate the single screw extruder? The following is a detailed introduction.

 

Here is the content list:

• Preparation work before starting the machine

• Start-up operation

• Stop operation

 

Preparation work before starting the machine

1. For single-screw extruder extrusion production of materials, should meet the required drying requirements, if necessary, further drying.

2. According to the variety of products, size, select the head specifications, the machine will be installed in the order of the column, installed head flange, die body, mouth die, porous plate, and filter network.

3. Connect the compressed air pipe, install the core mold electric heating rod head heating ring, check the water system.

4. Adjust the gap evenly in all parts of the mouth die and check whether the centerline of the main machine and the auxiliary machine are aligned.

5. Start the single-screw extruder of each running equipment, check whether the operation is normal, and find faults in time to eliminate.

6. Turn on the electric heater, the head, body, and auxiliary machine evenly heated up, to be the temperature of each part than the normal production temperature of about 10 degrees, constant temperature of 30 ~ 60 minutes so that the machine temperature inside and outside the same.

 

Start-up operation

Start-up is an important part of the production, poor control will damage the screw and head, the temperature is too high will cause plastic decomposition, the temperature is too low will damage the screw, barrel, and head. The start-up steps are as follows.

1. Start the machine at low speed, idle, check the screw for any abnormalities and motor, amperage meter current no overload phenomenon, the pressure gauge is normal. Machine idling should not be too long to prevent the screw and barrel-scraping grinding.

2. Gradually add a small amount of material, wait for the material extrusion out of the die, before the normal addition of material. Before the plastic is extruded, no one should be in front of the mouth die to prevent casualties.

3. After the plastic is extruded, it is necessary to lead the extruded material slowly on the cooling and shaping, traction equipment, and start this equipment beforehand. Then, according to the control instrument indication value and the requirements of the extruded products, each link will be properly adjusted until the extrusion operation reaches the normal state.

4. Cutting and sampling, checking whether the appearance meets the requirements, whether the size meets the standard, quickly testing the performance, and then adjusting the extrusion process according to the requirements of quality, so that the products meet the standard requirements.

 

Stop operation

1. Stop feeding, extrude the plastic in the single screw extruder and turn off the power of the barrel and head for the next operation.

2. Shut off the power of the main machine and the auxiliary machines at the same time.

3. Open the head connection flange, clean the porous plate and various parts of the head, when cleaning, should use copper rods, copper pieces, after cleaning, apply a little oil. Screw, barrel clean up, if necessary, the screw from the end of the machine out of the top, clean up after recovery, in general, available for the transition of material cleanup.

4. Extrusion of polyolefin plastics, usually in the extruder full load shutdown (with material shutdown), when the air should be prevented from entering the barrel, so as not to oxidize the material and affect the quality of the product when continuing production. For polyvinyl chloride plastics, can also stop with material, then close the material door, reduce the temperature at the head connection body (flange) 10 ~ 20 degrees, to stop the machine after the material squeeze net.

5. Close the total power and cooling water main valve.

 

If you still have questions, you can consult our company. Our company's website is https://www.njjyextrusion.com/

 

 

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.
Changing oil
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.

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?

What are the advantages of engineering plastic twin screw extruders?

1. wear

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.

What role do pre-heaters play in the use of engineering plastic twin screw extruders?

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.

What is the reason for the "fault" of the exhaust air opening of the engineering plastic twin screw extruder?

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 two types of hard and soft RPVC pipes, RPVC pipes are chemically resistant and insulating, mainly transporting various fluids and used as wire sleeves, etc. SPVC pipes are manufactured by extruding PVC resin with a large amount of plasticizer and a certain amount of stabilizer and other additives after granulation. The following is a detailed description of the equipment functions of the PVC compounding extruder.

 

Here is the content list:

• High Speed Mixer High-Speed Mixing

• Accurate matching of feeding device

• Water tank for pipe forming

• Traction machine frequency conversion speed control

• Automatic cutting

• Unloading the material from the turning frame

 

High Speed Mixer High-Speed Mixing

Raw material intermixture is to feature PVC stabilizer, softener, inhibitor, and different auxiliary materials to the high-speed mixer in proportion and sequence to the method.

Accurate matching of feeding device

The PVC compounding extruder part is equipped with a quantitative feeding device to match the extrusion volume with the feeding volume to ensure stable extrusion of products. Due to the characteristics of the conical screw, the feeding section has a larger diameter, and the heat transfer area and sheer speed of the material are larger, which is contributive to the plasticization of the fabric and also the little diameter of the screw within the metering section reduces the warmth transfer space and also the sheer speed of the soften so that the melt can be extruded at a lower temperature. When the screw rotates in the barrel, the PVC mixture is plasticized and pushed to the head to achieve compaction, melting, mixing, and homogenization and to achieve the purpose of exhaust and dehydration. The feeding device and screw drive device adopt frequency conversion to realize synchronous speed regulation.

PVC compounding extruder dies head part of the compacted, molten, blended, and homogenized PVC has subsequent materials through the screw to the die head extrusion die head is the key component of pipe forming.

Water tank for pipe forming

The vacuum shaping water tank of PVC compounding extruderis used for pipe shaping and cooling, the vacuum shaping water tank is equipped with vacuum system for shaping and cooling and water circulation system stainless steel box body circulating water spray cooling, the vacuum shaping water tank is equipped with front and rear moving device and left and right, high and low adjustment manual device.

Traction machine frequency conversion speed control

The traction machine is used to continuously and automatically lead the cooled and hardened pipe from the head with frequency control.

Automatic cutting

The cutting machine is controlled by the travel switch according to the required length and then automatically cut and delay the turning frame to implement the flow of production, the cutting machine with a fixed-length work switch signal as a command to complete the whole process of cutting in the cutting process and pipe running synchronization cutting process is completed by electric and pneumatic drive, the cutting machine is equipped with a dust suction device to suck out the cutting debris and recycling.

 

Unloading the material from the turning frame

The material turning action is controlled by the cylinder through the air circuit to achieve the material turning frame is equipped with a limit device when the cutting saw cut off the pipe after the pipe continues to transport after a delay, the cylinder into the work of turning action to achieve the purpose of unloading. After unloading, it will be automatically reset after a delay of several seconds to wait for the next cycle.

 

Nanjing JlEYA is the leading manufacturer extruder manufacturer specializing in 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 development, now we have 20,000 square meters workshop with annual sales 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 andother fields.

LAB TWIN SCREW EXTRUDER. Technovel has modernize the small twin screw extruders for R

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