Laboratory twin screw plastic extruder screw extruder is also called laboratory twin screw extruder. It is mainly used for research on polymer plastics. It is mainly used for research and development in universities, enterprises and research institutes. The main feature is that the screw diameter is small, which greatly reduces the amount of materials used in application research and development.

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Laboratory twin screw extruder test machine lab twin screw extruder

The auxiliary machines of the twin screw extruder unit mainly include wire release device, straightening device, preheating device, cooling device, traction device, meter counter, spark test machine, and wire take-up device. The auxiliary equipment selected for the extruder unit is different depending on its purpose, such as cutter, blow dryer, printing device, etc.

Directory

Structural features

Advantages

Application examples

Auxiliary equipment for laboratory twin-screw extruder test machine:

Differences between laboratory twin-screw extruder test machine and single-screw extruder

Daily maintenance of laboratory twin-screw extruder test machine:

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Edit this section Structural features

The notable features of the split co-directional parallel twin-screw extruder are: the barrel can be split. At the same time, the screw and the barrel liner can be used in combination at will.

1. Split barrel

The barrel of the previous laboratory twin-screw extruder test machine was integral and could not be opened. The split laboratory twin-screw extruder test machine is split, which consists of an upper and lower barrel. The lower barrel is fixed on the frame, and the upper barrel is connected to the lower barrel through a worm gear reduction. Normally, the upper barrel and the lower barrel are fastened with two rows of bolts. When the barrel needs to be opened, just loosen the bolts and turn the worm wheel to the handle to open the barrel.

2. Building block screw and barrel

The screw and barrel of the split laboratory twin-screw extruder experimental machine adopt the advanced "building block" design. The screw is composed of various forms of screw blocks mounted on the mandrel. The inner sleeve in the barrel can be adjusted according to the different screw blocks, so as to flexibly combine the ideal screw element structure according to the process requirements such as material variety, realize the various process processes such as material transportation, plasticization, refinement, shearing, discharge reduction, decompression and extrusion, so as to better solve the contradiction between the so-called universality and speciality of the screw, which is generally difficult to take into account, and achieve the purpose of one machine with multiple uses and one machine with multiple functions. Another advantage of the "building block" design is that the worn screw and barrel elements can be partially replaced, avoiding the scrapping of the entire screw or barrel, and greatly reducing the maintenance cost.

1. The twin screws of the main machine are high-speed co-rotating meshing type, which can produce very strong and complex material transfer exchange, diversion blending, shearing and kneading in various threads and mixing elements. These effects can be fully and freely adjusted and controlled by changing the screw configuration and operating process conditions to meet the requirements of various processes.

2. Accurate measurement and reasonable feeding method are the key to strictly implement the formula and the first step to ensure product quality. According to the performance of the material and the needs of the user, we are equipped with a variety of feeding methods, such as volume measurement, dynamic weight loss measurement, etc., to meet the needs of different products.

3. Advanced control system. The extruder is equipped with an advanced and beautiful control system. Most of its space control components are imported components with good quality and high sensitivity. The operating parameters of the main machine such as current, voltage, temperature, torque, etc. are very intuitive, so it is very convenient to operate and the requirements for operators are not high.

4. The system is equipped with several pelletizing methods such as wire drawing water cooling pelletizing, hot cutting water cooling, hot cutting air cooling, etc. It can be configured according to different materials and user requirements.

Edit this paragraph Advantages

1. Intuitively understand the wear of wearing parts

Because it is easy to open, the wear degree of threaded components and barrel liner can be found at any time, so as to carry out effective repair or replacement. It is not discovered when there is a problem with the extruded product, causing unnecessary waste.

2. Reduce production costs

When manufacturing masterbatch, it is often necessary to change the color. If it is necessary to change the product, open the open processing area within a few minutes. In addition, the mixing process can be analyzed by observing the melt profile on the entire screw. At present, when changing the color of ordinary laboratory twin-screw extruder test machines, a large amount of cleaning materials are needed to clean the machine, which is time-consuming, power-consuming, and wasteful of raw materials. The split laboratory twin-screw extruder test machine 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 materials are needed, saving costs.

3. Improve labor efficiency

When repairing the equipment, ordinary laboratory twin-screw extruder test machines often have to remove the heating and cooling systems first, and then pull out the screw as a whole. However, the split twin-screw does not need to be repaired. Just loosen a few bolts, turn the worm gear box handle device to lift the upper part of the barrel to open the entire barrel, and then repair it. This not only shortens the maintenance time, but also reduces labor intensity.

4. High torque and high speed

At present, the development trend of laboratory twin-screw extruder test machines in the world is to develop in the direction of high torque, high speed and low energy consumption. The effect of high speed is high productivity. The split laboratory twin-screw extruder test machine belongs to this category, and its speed can reach 500 rpm. Therefore, it has unique advantages in processing high-viscosity and heat-sensitive materials.

5. Wide range of applications

Wide range of applications, suitable for processing a variety of materials

6. High output, high quality, high efficiency

It has other advantages of ordinary laboratory twin-screw extruders, and can achieve high output, high quality and high efficiency.

Edit this section Application examples

1. Granulation of glass fiber reinforced and flame retardant materials (such as: PA6, PA66, PET, PBT, PP. PC reinforced flame retardant, etc.)

2. Granulation of high filler materials (such as: PE, PP filled 75%CaCO. )

3. Granulation of heat-sensitive materials (such as PVC, XLPE cable materials)

4. Concentrated color masterbatch (such as: filled with 50% color powder)

5. Antistatic masterbatch, alloy, coloring, low filling blending granulation

6. Granulation of cable materials (such as: sheath materials, insulation materials)

7. Granulation of XLPE pipe materials (such as: masterbatch for hot water cross-linking)

8. Mixing and extrusion of thermosetting plastics Out (such as: phenolic resin, epoxy resin, powder coating) 9. Hot melt adhesive, PU reaction extrusion granulation (such as: EVA hot melt adhesive, polyurethane) 10. K resin, SBS devolatilization granulation Edit this section Laboratory twin screw extruder test machine auxiliary equipment: Straightening device The most common type of plastic extrusion waste is eccentricity, and various types of bending of the core are one of the important reasons for insulation eccentricity. In sheath extrusion, scratches on the surface of the sheath are often caused by the bending of the cable core. Therefore, straightening devices in various extrusion units are indispensable. The main types of straightening devices are: drum type (divided into horizontal and vertical types); pulley type (divided into single pulley and pulley group); winch type, which also plays multiple roles such as dragging, straightening, and stabilizing tension; pressure wheel type (divided into horizontal and vertical types), etc.

Preheating device

Cable core preheating is necessary for both insulation extrusion and sheath extrusion. For the insulation layer, especially the thin layer insulation, the existence of pores is not allowed. The wire core can be completely cleaned of surface moisture and oil by high temperature preheating before extrusion. For sheath extrusion, its main function is to dry the cable core to prevent the possibility of pores in the sheath due to moisture (or moisture in the wrapping cushion layer). Preheating can also prevent the residual internal pressure of the plastic due to sudden cooling during extrusion. In the process of extruding plastic, preheating can eliminate the large temperature difference formed when the cold wire enters the high-temperature die and contacts the plastic at the die mouth, avoid the fluctuation of the extrusion pressure caused by the fluctuation of the plastic temperature, thereby stabilizing the extrusion volume and ensuring the extrusion quality. Electric heating wire core preheating devices are used in extrusion units, which are required to have sufficient capacity and ensure rapid heating, so that the wire core preheating and cable core drying efficiency are high. The preheating temperature is restricted by the pay-off speed, and is generally similar to the die temperature.

Cooling device

After the formed plastic extrusion layer leaves the die, it should be cooled and shaped immediately, otherwise it will deform under the action of gravity. The cooling method usually adopts water cooling, and it is divided into rapid cooling and slow cooling according to the different water temperatures. Rapid cooling is direct cooling with cold water. Rapid cooling is beneficial to the shaping of the plastic extrusion layer, but for crystalline polymers, due to sudden heat cooling, it is easy to leave internal stress inside the extrusion layer, resulting in cracking during use. Generally, the PVC plastic layer adopts rapid cooling. Slow cooling is to reduce the internal stress of the product. Water of different temperatures is placed in the cooling water tank in sections to gradually cool down and shape the product. Slow cooling is used for the extrusion of PE and PP, that is, it is cooled in three stages of hot water, warm water and cold water.

Edit this section The difference between laboratory twin-screw extruder and single-screw extruder

Single-screw machine and twin-screw machine: one is one screw and the other is two screws. Both are driven by one motor. The power varies with different screws. The power of 50 cone twin is about 20KW, and that of 65 is about 37KW. The output is related to the material and the screw. The output of 50 cone twin is about 100-150KG/H, and that of 65 cone twin is about 200-280KG/H. The output of a single screw is only half. Extruders can be divided into single screw, twin screw and multi-screw extruders according to the number of screws. At present, single screw extruders are the most widely used and suitable for extrusion processing of general materials. The laboratory twin screw extruder test machine has less heat generated by friction, more uniform shearing of the material, larger conveying capacity of the screw, more stable extrusion volume, longer material stay in the barrel, and uniform mixing.

SJSZ series conical laboratory twin screw extruder test machine has the characteristics of forced extrusion, high quality, wide adaptability, long life, low shear rate, difficult material decomposition, good mixing and plasticizing performance, direct powder molding, etc., temperature automatic control, vacuum exhaust and other devices. It is suitable for the production of products such as tubes, plates, and special-shaped materials.

Single-screw extruders occupy an important position as both plasticizing and granulating machinery and molding processing machinery. In recent years, single-screw extruders have made great progress. At present, the large-scale single-screw extruders for granulation produced in Germany have a screw diameter of 700mm and an output of 36t/h.

The main sign of the development of single-screw extruders lies in the development of its key parts-the screw. In recent years, people have conducted a lot of theoretical and experimental research on screws. So far, there are nearly 100 types of screws, including separation type, shear type, barrier type, diversion type and wavy type.

From the perspective of single-screw development, although single-screw extruders have been relatively perfect in recent years, with the continuous development of polymer materials and plastic products, more characteristic new screws and special single-screw extruders will emerge. Generally speaking, single-screw extruders are developing in the direction of high speed, high efficiency and specialization.

The laboratory twin-screw extruder has good feeding characteristics and is suitable for powder processing. It has better mixing, exhaust, reaction and self-cleaning functions than the single-screw extruder. It is more superior when processing plastics and blends with poor thermal stability. In recent years, foreign laboratory twin-screw extruders have made great progress. Various forms of laboratory twin-screw extruders have been serialized and commercialized. There are also many manufacturers, which can be roughly classified as follows:

(1) According to the relative position of the two axes, there are parallel and conical types;

(2) According to the meshing process of the two screws, there are meshing and non-meshing types;

(3) According to the rotation direction of the two screws, there are same direction and opposite direction, and in opposite direction, there are inward and outward; ¡õ

(4) According to the screw rotation speed, there are high speed and low speed;

(5) According to the structure of the screw and barrel, there are integral and combined types.

On the basis of the laboratory twin-screw extruder test machine, in order to more easily process blends with poor thermal stability, some manufacturers have developed multi-screw extruders such as planetary extruders, etc.

Edit this section Daily maintenance of laboratory twin-screw extruder test machine:

Daily maintenance method of laboratory twin-screw extruder test machine:

1. After 500 hours of use, there will be iron filings or other impurities in the gearbox, so the gears should be cleaned and the gearbox lubricating oil should be replaced.

2. After using it for a period of time, the extruder should be fully inspected to check the tightness of all screws.

3. If there is a sudden power outage during production, the main drive and heating stop. When the power supply is restored, the barrel sections must be reheated to the specified temperature and kept warm for a period of time before the extruder can be started.

4. If the full degree of steering of the instrument and pointer is found, the contact of the thermocouple and other side lines should be checked to see if they are in good condition.

Configuration:

Different equipment can be added according to different needs, such as adding film blowing machines, cast film machines, and bottle blowing machines. Multiple twin-screw extruders can be configured according to needs to form multi-layer film blowing machines and multi-layer cast film machines. Of course, there is no problem with multi-layer bottle blowing machines, but few friends ask about it. Generally, there will be more demand for multi-layer film blowing machines and multi-layer cast film machines.