In the extruder, in general, the most basic and most versatile is a single screw extruder. It mainly includes six parts: transmission, feeding device, barrel, screw, machine head and die.
The transmission part is usually composed of an electric motor, a reduction gear box and bearings. During the extrusion process, the screw speed must be stable and cannot change with the change of the screw load, so as to maintain the uniform quality of the obtained product. However, in different occasions, the screw can be required to be shifted to achieve the requirement that one device can extrude different plastics or different products. Therefore, this part generally uses AC commutator motor, DC motor and other devices to achieve stepless speed change, the general screw speed is 10~100 rev / min.
The function of the drive system is to drive the screw, which supplies the torque and speed required by the screw during the extrusion process, usually consisting of a motor, a reducer and a bearing. Under the premise that the structure is basically the same, the manufacturing cost of the reducer is roughly proportional to its external dimensions and weight. Because the shape and weight of the reducer are large, it means that there are many materials consumed during manufacturing, and the bearings used are also relatively large, which increases the manufacturing cost.
In the same screw diameter extruder, the high-speed and high-efficiency extruder consumes more energy than the conventional extruder, and the motor power is doubled. It is necessary to increase the frame number of the reducer. But a high screw speed means a low reduction ratio. The same size of the reducer, the low reduction ratio compared to the large reduction ratio, the gear modulus increases, the reducer's ability to withstand the load also increased. Therefore, the increase in the volumetric weight of the reducer is not linearly proportional to the increase in motor power. If the derivation is used as the denominator, the speed of the reducer is divided, the number of high-speed and high-efficiency extruders is small, and the number of ordinary extruders is large. In terms of unit output, the motor power of the high-speed high-efficiency extruder is small and the weight of the reducer is small, which means that the unit production cost of the high-speed and high-efficiency extruder is lower than that of the ordinary extruder.