Like the screw, the barrel also works under high temperature, high pressure, high load friction and certain corrosive conditions. The barrel also has the effect of transferring heat to or from the material.
1. The structure of the barrel. The barrel structure is available in both integral and assembled versions.
The overall barrel is machined from the monolith. The structure is characterized by easy to ensure high manufacturing and assembly precision, easy to set up and disassemble the heating and cooling system, and the barrel is heated evenly, but the machining requirements are high.
The assembly cylinder is generally composed of several barrel segments. It is characterized by easy processing compared with the overall barrel and can be changed according to the requirements of use and various types of products. However, this structure requires more processing precision. High, each barrel is connected by flanges and bolts, which destroys the uniformity of barrel heating, increases heat loss, and is not convenient for setting and maintenance of heating and cooling system.
The material of the barrel is generally: alloy copper such as 30Cr and 38CrMoAL. Carbon steel or cast steel can also be used to make the alloy steel bushing in the base material to improve the wear resistance.
2. The form of the barrel feeding section. In order to improve the conveying capacity of the solid, one method is to open a longitudinal groove in the inner wall of the feeding section barrel, and the other method is to make the feeding section taper to a barrel of the hopper. The longitudinal groove in the nose can only be about 3-5D in the section before the material is still solid or begins to melt.
The taper of the inner wall of the barrel is generally 3-5D. The size of the taper depends on the size of the material particles and the diameter of the screw, and the taper is reduced as the screw diameter increases.
3. The shape and position of the feeding port. The shape of the feed opening and its opening position on the barrel have a great influence on the feeding performance. The feeding port should enable the material to be freely and efficiently added to the barrel without creating a "bridge" phenomenon, which is convenient for setting up the cooling system. The shape of the feeding port is circular, square, rectangular, etc., and generally rectangular.