Nanjing Rubber & Plastics Machinery Plant

A twin screw extruder is not a simple combination of two single screws. In addition to the nuclear space between twin screw and barrel, there are side gap, the tetrahedron gap and calendaring gap. Mating-type twin screw extruder can be divided into full meshing engagement and a part one and the entire mating type can be further subdivided into conjugate and non-conjugated type. It is interrelated among different geometric parameters, such as screw diameter, screw head, screw edge width, the center distance. Due to the different geometric parameters, the horizontal spiral flow channel slot of twin screw extruder can be opened. It is geometric complexity that can distinct single screw extruder and twin screw extruder fundamentally.

Screw extruder including single screw extruder and twin screw extruder, is the most commonly used method of polymer processing, and it was in 1930s that twin screw extruder came into being era.

In accordance with the direction of the two screws’ relative rotation, an extruder can be divided into two broad categories: the rotation and varies with the rotating. In 1960s, appearing on behalf of the two axes is not parallel conical twin screw extruder machine, which belongs to the counter-rotation. With high stability, counter rotating twin screw extruder is mainly used for pipe, profile and so on, demanding cross-section size extrusion products and it is used as a host in the current window and door profile production. Co-rotating twin screw extruder is applied for mixing, and mixture occupies an important position in polymer processing (above the polymer need to be final products before going through the mixture screw). Nowadays, the extrusion system of co-rotating twin screw extruder mainly uses modular structure, the barrel assembly, and the screw components.

This stabilizator can heat and control pressure screw to make sure the polymer in pressure screw keep in molten state and drive motor connected with pressure screw though reducer. In the working process of extruder, extruder system will produce pressure in head of extruder; and polymer melt is pushed into parallel pressure ptabilizator and makes polymer melt keep in pressure screw within a certain length. On the other hand, pressure fluctuation will also change remaining length of polymer melt in pressure screw. The stabilizator can be adjusted its installation position and angle from from the longitudinal and transverse two directions and it is convenience for disassembly and cleaning.

Actually, the stabilizator can be seen as a parallel single screw pumping device which has stabilization effect between extruder and its head. The part betwen pressure screw and extruder appears as the form of parallel connection, so there will be a pressure value just the same as extruder system.

There is three-dimensional flowfield of the melt conveying zone in an intermeshing counter-rotating twin screw extruder. Nowadays, the research about twin screw extrusive process main focus on the step of fuse-element output. This is because the output characteristics of materiel in this section clearly affect the performance characteristics of twin screw extruder and the solution of molten ingot flow process can take research achievements of hydrodynamics as reference. Rotational direction of screw must maintain a certain relationship with the rotational direction of thread in order to make sure that the materials can transfor from the charging hole to the head of extruder.

A mathematical model of the parallel pressure stabilizator for a single screw extruder was proposed.The results of simulation by the proposed model indicated that by means of changing the speed of the subsidiaryscrew in the stabilizator and the self-adjusting length of the filled melt polymer , the stability of the pressure and production rate of the extruder can be effectively improved.

Plastic is melt into homogeneous melt plastics by a twin screw extruder, and can make the head of the extruder with constant temperature, constant quality and constant pressure under the pressure created in the process of plasticization. This is also the way which is used on most thermoplastic plastic. Extruders have different kinds of type and etalon， among which twin screw extruder is the most common one.

The technological requirement can be satisfied and the technological control index can be reached by the wheeling of the mainframe of twin screw extruder, which uses the kv2000 AC frequency converter.

From long stable practical operation of each place, it is obvious that twin screw extruder has a strong adaptability that can bring significant economic benefits to our society.

The competition of single screw extruder is pretty strong in international plastics market. In order to ensure the expansion of its market share of extruder, it is necessary for extruder manufacturers to improve their equipment reliability, reduce costs and ensure that the manufacturing process of products doesn’t be interfered.

It is essential to choose machines and components with high reliability.Extruder manufacturers begin to involve tubes and the membrane system in the huge market of single screw extruder.

There are a variety of requirements for the speed box of single screw extruder:

◆ the axial force in the process of absorbing and extruder
◆ to provide high torque
◆ to push the screw out from the drive side
◆ to resist overloading
◆ gear without limit life
◆ high efficiency
◆ low Noise
◆ high reliability
◆ excellent price / performance ratio

In recent years, twin screw extruder extremely has a strong market, but relatively speaking, single screw extruder has been in a state of silence. However, the single screw extruder, as basic plastic processing equipment, enjoys the fame of simple structure, lower cost and greater design flexibility. A variety of special single screw extruders now have attracted people’s attention.

Screw extruder because of its simple structure, good value for money and high production efficiency, has been playing an important role of processing, like the formation of plastic pipe, plate, sheet, etc. With the continuous advancement of technology, as well as people’s awareness of screw extruder, a number of extruders with different structure have come into being.

In recent years, twin screw extruder is in a high rate of development. However, due to more and more studies on extrusion technology and continuous improvement, it is a tendency that special single screw extruder will replace multi-screw extruder in processing technology.

Twin screw plastics processing technology has become very common in industrial applications, so that competition is extremely fierce. Different suppliers of twin screw extruder have been offering their own unique features and innovative technologies in order to win the twin screw extruder market.

1) High-speed, high-volume: high-speed, high efficiency, energy saving in recent years have been the main theme of the continuous improvement in international plastics industry. The potential for solving problems caused by high-speed is one of the major directions for suppliers of
technological innovation in twin screw extruder.

2) Multi-function: In the function, twin screw extruder is no longer limited to polymer materials and the mixing of the molding, and its use has been extended to food, feed, explosives, construction materials, packaging, paper and ceramics and other fields.

3) Large-scale and precision: the realization of large-scale extrusion equipment can reduce the production cost, and precision can improve the value of products.

4) Intelligent and networking: the technological transformation in the equipment itself, the advanced twin screw extruders have been widely used with computer control ,online monitoring and control process conditions in extrusion process s, which can ensure the stability, improve the accuracy of product.