in recent years, the co-rotating twin-screw extruder has developed rapidly, and its output, torque and rotational speed have been greatly improved, and its application has become increasingly widespread. Increasing the production efficiency of the co-rotating twin-screw extruder, improving the product quality and realizing the multi-functionality of the equipment are the basic requirements for achieving high performance, and it is also the difficulty of research and development.
Increasing production efficiency is one of the important goals of the development of a new co-rotating twin-screw extruder, which can be achieved by increasing the screw speed, enhancing plasticization and mixing capabilities.
At the same screw speed, increasing the depth of the groove can greatly increase the amount of conveyance. Correspondingly, the plasticizing and mixing ability of the screw is also required to increase, which requires the screw to withstand greater torque. At high screw speeds, the residence time of the material in the extruder is reduced, which may make the material plasticized and melted, and the mixing is insufficient. To this end, it is necessary to appropriately increase the length of the screw, which in turn leads to an increase in the actual load torque and power of the twin-screw extruder.
Increasing the free volume of the groove is also an important factor. In the feeding section and the devolatilization section, it is necessary to have a large free volume of the threaded element. For the bulk material, increasing the free volume of the feeding section and the fullness of the material in the groove can greatly improve the production of the extruder. ability.
To increase the torque and speed, the deceleration distribution box needs to be carefully designed. To greatly increase the torque index of the equipment, higher requirements must be placed on the design and manufacturing level of the transmission box. The higher the torque, the higher the design, manufacturing precision, material strength and heat treatment requirements of the gears, output shafts, bearings and other parts in the gearbox. At the same time, the design and manufacturing precision requirements of the screw mandrel, threaded components and kneading discs are also required. higher. Because the free volume of the threaded element is to be increased, the center distance of the two screws will be reduced with the outer diameter of the screw unchanged, which will certainly make the problem of insufficient installation space of the proportioning gear and the thrust bearing become more prominent.
improve product quality
In order to obtain high product quality, the design of the plasticizer system, the core component of the extruder, is of great importance.
The plasticizing system mainly includes a screw and a barrel. In order to meet various processing requirements, the screw and the barrel are usually designed into a modular structure. According to the function of each section, the screw can be divided into a feeding section, a plasticizing section, a mixing section, an exhaust section and an extrusion section. These sections have different functions in the extrusion process, their structures are different, and the corresponding screw element geometric parameters are also different. Therefore, how to determine the geometrical parameters of the threaded components becomes the key to the design of the plasticizing system.