How to use the extruder screw and barrel

Extruder screw barrel contain a feed pocket that carries plastic pellets into the barrel. The depth and volume of the feed channel gradually decreases during the transition section, causing a restriction in the pellet's forward path. This causes the pellets to compact until there is no free volume between them. Once this happens, the pellets form a solid bed. This bed causes tremendous pressure during the compression section of the screw as the pellets move as one mass and create intense friction against the barrel wall.The extruder screw and barrel form the heart of the extrusion process. All other components support the screw and barrel. The screw and barrel perform three vital functions: feeding, compacting, and melting. Let's look at these functions and how they work. The first step in the extrusion process is feeding plastic pellets.

Extruder screw barrel for PVC plastic machine


Oftentimes, a broken or damaged extruder screw will lead to a lower performance and decreased service life. To avoid such an outcome, consider using a bimetallic screw barrel. It will help you avoid premature wear and tear while saving energy and maintenance costs. The bimetallic screw barrel will also help counteract friction and reduce energy consumption.Another important consideration is the speed of heating the barrel. The temperature needs to be regulated, and a barrel with a fast heating rate will improve plasticization capacity. The heating time of small machines is about 30 minutes, while large machines can take up to an hour to reach the desired temperature. During this time, the extruder screw barrel must be equipped with a heat exchanger and a large stainless steel water tank. The cooling system should be designed to accommodate softening water and regulate the flow of water through a solenoid valve.

If the gap is too large, the extrusion melt pressure will be unstable and the product will be uneven or may have size errors.The gap should be small enough to prevent the melt from flowing backwards. Otherwise, the extruded product will have a discolored surface and focal spots. It will also decrease the output of the extrusion process.The screw barrel of a plastic extruder plays an important role in the process. It will help you control the flow of material as you process it through the extruder. When you select the right screw barrel, it will make the whole process easier and faster. You can choose from a wide variety of designs and specifications.The wear of a screw barrel can affect the productivity of the extruder. While minor wear is not harmful, it can decrease throughput.

It can also increase the temperature of the melt. In either case, you can adjust the settings so that the screw barrel keeps running efficiently. In case of a screw that is too worn or has too little clearance, you can adjust its radial clearance.When selecting the right screw barrel for your application, you must take into account its inner and outer diameters. The size of the barrel can vary from 14 mm to 300 mm. Make sure to consult an expert if you're unsure of which is best. It is best to use an OEM company's spare parts drawings, which are available in AutoCAD format. They should include all material details, dimensions, and machining requirements.