Extruder classification and its structure
Extruders are generally divided into single-screw extruders, twin-screw extruders, and multi-screw extruders in terms of the number of screws. Screw extruder consists of four parts: plasticizing system, heating and cooling system, transmission system and electrical control system.
The main component of the plasticizing system is the screw, and different types of screws are selected according to the type of plastic and its products. The screw diameter of commonly used extruders is 30 to 250 mm, and the rotation speed is 30 to 300 r/min. The length of the screw is usually 20 to 25 times of the diameter, and the maximum is 30 times. The extruder barrel is heated by an electric heater and cooled with water or air. The extruders used in screw extruders are mostly commutator motors or DC motors.
At present, the single-screw extruder is the most widely used and suitable for extrusion processing of general materials. The twin-screw extruder has less heat generated by friction, the shearing of the material is relatively uniform, the conveying capacity of the screw is larger, the extrusion amount is relatively stable, the material stays long in the barrel, and the mixing is uniform. SJSZ series conical twin-screw extruder has the characteristics of forced extrusion, high quality, wide adaptability, long service life, small shear rate, difficult material decomposition, good mixing and plasticizing performance, direct molding of powder, and temperature control. Vacuum exhaust and other devices.
In recent years, a large number of theoretical and experimental studies have been carried out on the screw. Up to now, there have been nearly a hundred kinds of screws, and the common ones are separation type, shear type, barrier type, split type and wave type. From the standpoint of single screw development, although single screw extruders have been relatively complete in recent years, with the continuous development of polymer materials and plastic products, new types of special screw and special single screw extruders will emerge.
In plastic extrusion molding equipment, plastic extruders are often referred to as mainframes, and their accompanying follow-up equipment, plastic extrusion molding machines, are called auxiliary machines. After more than 100 years of development, plastic extruders have derived twin screw, multi-screw, and even screwless models from the original single screw. It is believed that in the future, the technology of the plastic extruder industry will have a qualitative leap, and it will no longer depend on imports. In the international arena, the influence will continue to rise, and the development prospects are optimistic.
China’s plastic extruder industry is advancing toward health, from scratch, from import to production, from the simulation to the self-refurbished development process is always unconvincing development process, lack of license is familiar with our company’s ability to produce their own production Discovered my own plastic extrusion machinery to meet our own needs or even the world’s needs
- Intuitively understand the wear of consumables Because it is easy to open, you can always find the degree of wear of threaded elements and sleeves in the barrel, so as to perform effective maintenance or replacement. It will not be discovered when there is a problem with the extruded product, causing unnecessary waste.
- Reduce production costs When manufacturing masterbatch, it is often necessary to change the color. If it is necessary to replace the product, open the open type processing area within a few minutes. In addition, the mixing process can also be performed by observing the melt profile on the entire screw.analysis. At present, an ordinary twin-screw extruder requires a large amount of cleaning materials to perform the cleaning when changing colors, which is time-consuming, power-consuming and wastes raw materials. The split twin-screw extruder can solve this problem. When the color is changed, the barrel can be quickly opened in a matter of minutes to carry out manual cleaning, so that no or little cleaning materials can be used and the cost can be saved.
3, improve labor efficiency In the maintenance of equipment, the ordinary twin-screw extruder often has to first remove the heating and cooling system, and then extract the screw. The split-type twin-screw is not used. Just loosen a few bolts and turn the worm gear handle to raise the upper half of the barrel to open the entire barrel and then perform maintenance. This will not only shorten the maintenance time, but also reduce labor intensity.
- High torque and high speed At present, the development trend of twin-screw extruders in the world is to develop toward high torque, high speed and low energy consumption. The effect brought by high speed is high productivity. Split twin-screw extruders fall into this category, with speeds up to 500 rpm. Therefore, it has unique advantages in processing high-viscosity and heat-sensitive materials.
In the core technology of high-speed, high-torque, asymmetric and symmetrical high-torque gearboxes currently have only German and Japanese related manufacturers to master the core technology, and their maximum speed can reach 1800 or more, while the domestic master of this core technology, Only Sichuan Zhongzhuang Technology Co., Ltd. is currently one of the main choices of high-end material processing companies in China, and it is a national incentive project for independent innovation.
5, a wide range of applications A wide range of applications can be applied to the processing of a variety of materials.
6, high yield, high quality, high efficiency has the other advantages of ordinary twin-screw extruder, can achieve high yield, high quality, high efficiency.
