In the plastic granulation line, a twin-screw granulator and a single-screw granulator can generally be used. Whether it is a twin-screw granulator or a single-screw granulator, the main body is an extruder, and the barrel and screw on the extruder are single screw and barrel the most important plasticizing systems. The China Plastics Machinery Research Institute focuses on the barrel of a single-screw extruder.
In the plastic granulation line, a twin-screw granulator and a single-screw granulator can generally be used. Whether it is a twin-screw granulator or a single-screw granulator, the main body is an extruder, and the barrel and screw on the extruder are the most important plasticizing systems. This article focuses on the barrel of a single screw extruder. The barrel can also be called a barrel. Like the screw, it works under high pressure and high temperature, severe wear and certain corrosion conditions. The barrel also has the effect of transferring heat to the plastic or transferring heat away from the plastic. The barrel of a single screw granulator is generally divided into a unitary type and a segmented type. The monolithic barrel is machined from an integral alloy such as 30Cr or 28CrMoAl.
In general, small plastic extruders use an integral barrel. Large plastic extruders (with a screw diameter of 90 mm or more) use general carbon steel or cast steel as the base. Made of inlaid alloy steel bushing. The integral barrel is characterized by a long length and high processing requirements. It is easy to guarantee the machining accuracy and assembly accuracy. The integral barrel is heated evenly, which is generally used by professional manufacturers, but it is difficult to repair after the inner surface of the barrel is worn. The segmented barrel is a combination of several barrels. Then the segments are connected by flanges or other forms. The materials used are the same as the monolith. The machining of this barrel is simpler than the one-piece barrel.
It is easy to change the aspect ratio and can be used in laboratory extruders that need to change the aspect ratio of the screw. However, since it is difficult to ensure the alignment of the segments due to too many segments, the flange connection affects the uniformization of the barrel heating.
