An extruder is the main machine of an extrusion line, which plasticizes and conveys materials and provides the required pressure for the products. Extruders exist as the main equipment for processing many types of products and have been widely used in many countries and China. And have become a series of machinery products with many specifications. There are many extruder types, and the relevant parameters express their range of use and performance indicators.
So how many types of extruder are there?
We can classify Extruders into twin-screw extruders, single-screw extruders, and, less frequently, multi-screw extruders and screwless extruders. The screw extruder relies on the pressure and shear force generated by the rotation of the screw, which allows the material to be fully plasticized and uniformly mixed, and then molded through the mouth die.
The classification of extruders is as follows：
1, according to the number of screws, can divide it into single-screw, twin-screw, and multi-screw extruder.
2, according to whether the exhaust can divide into the exhaust and non-exhaust extruder.
3, according to the position of the screw, can be divided into vertical and horizontal extruders.
In the extruder, in general, the most basic and common is the single-screw extruder. Its main components include transmission, charging device, barrel, screw, head, mouth die, and other six parts. The twin-screw extruder has the characteristics of less heat generated by friction, more uniform shear to which the material suffers, larger conveying capacity of the screw, more stable extrusion volume, long stay of the material in the barrel, and uniform mixing, etc. It is also more widely used.
Differences between the two types of extruders:
Single-screw machine and twin-screw machine: one is a screw, one is two screws, a motor drives both, the power varies depending on the screw, the output is related to and screw, the production of a single screw is only half.
The twin-screw extruder has forced extrusion, high quality, wide adaptability, long life, low shear rate. The material is not easy to decompose, mixing and good plasticizing performance, direct powder molding, and other characteristics. The temperature is self-control, vacuum exhaust, and other devices. Therefore, it is suitable for the production of products such as tubes, plates, shaped materials.
Single-screw extruder, whether as plasticizing granulation machinery or molding processing machinery, occupies an important position. At present, single-screw extruder has a great development. The main sign of the development of a single-screw extruder is the development of its key components – screw. Recently, people have conducted a lot of theoretical and experimental research on the screw. There are nearly 100 kinds of screws, common separation type, shear-type, barrier type, diversion type, and wave type.
From the perspective of single screw development, although the single-screw extruder has been near perfect, with the continuous development of polymer materials and plastic products, the new screw and special single-screw extruder will be more characteristics. In general, the single-screw extruder to high-speed, high-efficiency, specialized direction.
Twin-screw extruders have good feeding characteristics, suitable for powder processing. In addition, they have better mixing, exhaust, reaction, and self-cleaning functions than single-screw extruders, characterized by the poor thermal stability of the processing of plastics and co-mingled materials to show their superiority. In recent years, domestic and foreign twin-screw extruders have been a great development. Various forms of twin-screw extruders have been serialized and commercialized, producing more manufacturers. As a result, it will develop more and more perfectly.
The Food Extruder Machine currently on the market is mainly a twin-screw extruder that can produce various uncoated, coated or sandwich cereal snacks with multiple formulations and shapes. Food Extruder Machines use twin-screw extrusion technology and are highly flexible. Therefore, they can be easily converted into machines to process new products such as sandwich products, cornflake snacks, or crumb snacks with just a few easy additions to auxiliary equipment.
Food Extruder Machine uses corn, rice, wheat, oats, barley, etc., as raw material to make snacks. The grains are cooked in the extruder by the friction between screw and barrel. And the forming is done at the die face tool. The combination of die apertures determines the shape of the product. By adjusting the dies in the extruder, the machine can provide various forms such as spheres, tubes, bars, rings, fruit rings, stars, wheels, flowers, and hearts.
Among several types of extruders, screw extruders are using widely, and twin-screw extruders are the best extrusion equipment for foodstuffs, bringing many conveniences and high economic benefits to food processing enterprises. We believe that with the development of science and technology, extruders will have a broad development prospect.