Process Points of Twin Screw Extruder

In many chemical companies, twin-screw extruders are needed. Because of its good working performance and high efficiency, it is favored by many companies. In this article, we give you a detailed introduction to the process points of the twin-screw extruder and the analysis of the problems in the use process.

Process points of twin screw extruder

1. During the extrusion process, the material is transformed from the glass state to the molten state. In addition to the balance between the heat required for plasticization of the material and the heat supplied to make the material complete the ideal plasticization, melt pressure is also a very important control index. Because the material is affected by the resistance of the die and the compression ratio of each section of the screw during the extrusion process, it does not exist under normal pressure. For different die, the compression ratio of each section of the screw is constant and immutable.

2. Under the premise of the same extrusion speed, increase or decrease the feed rate, the volume of the screw material in the feeding section will change, and the volume of the material in the exhaust section will remain unchanged. Therefore, as the compression ratio changes in the feeding section and compression section, the melting pressure increases or decreases accordingly. Under the premise that the feeding speed is constant, increasing or reducing the extrusion speed will change the volume of the screw material in the feeding section.

The volume of the material in the exhaust section remains unchanged, so the feed section and compression section change with the compression ratio, and the melt pressure increases or decreases accordingly. The feeding speed increases or decreases synchronously with the extrusion speed. Because the volume of the screw material in the feeding section remains unchanged, the melt pressure changes only due to the increase or decrease of the speed.

Problem analysis of twin screw extruder

1. The reamer is severely worn

The gap between the reamer and the inner wall of the mud tank is too large, or the helix angle of the reamer blade is incorrect. When replacing the reamer, care should be taken to keep the gap of 3-5 mm, and the reamer blades should be made according to the designed angle.

2. The surface is too rough

The surface of the reamer blade is too rough, and the friction between the mud and the blade is too large. When surfacing the reamer, do not build up in groups, replace them all at once, and replace them in batches step by step to ensure smooth brick output.

3. Severe wear of the mud tank wall bushing

The gap between the reamer blade and the mud tank wall is too large, which causes the mud to rotate too much in the mud tank, and the mud cannot come out or get in. At this time, a new mud tank liner should be replaced, or several ribs parallel or inclined to the axial direction should be installed on the inner wall of the liner to replace the rifle grooves that have been worn away and prevent the ineffective rotation of the mud.

4. The gap is too large

The clearance between the mud pressing blade and the reamer is too large to hold down the mud. At this time, the blade should be adjusted or repaired and updated so that the gap between the blade and the reamer blade is less than 10 mm.

Do you now know how to better display the real performance of the extruder? Chuangbo is a professional twin screw extruder manufacturer and supplier in China. We can provide customers with different extruders with excellent performance, such as masterbatch extruder, PVC compounding, thermoplastic elastermor, reaction extrusion line, devolatilization extruder, pelletizing system, etc.