Plastic extruder barrel wear maintenance method and precautions

The barrel wear of the plastic extruder is mainly manifested in the wear of the barrel, which causes the diameter of the inner diameter of the barrel to increase. The hardness of the barrel is higher than that of the screw because the inner surface hardness is higher than that of the screw. The following items should be noted in the barrel maintenance method and repair process:

1. The barrel is increased in diameter due to wear. If there is a certain layer of nitriding, the inner hole of the barrel can be directly grinded to obtain a new diameter size, and then a new screw is prepared according to the new diameter.

2. Through machining, the inner diameter of the barrel is recast and alloyed, the thickness is controlled between 1~2mm, and then finished to the necessary new size.

3. Under normal circumstances, the barrel homogenization section wears faster than other positions. The homogenization section pupil can be trimmed, and then a nitriding alloy steel bushing is used. The diameter of the inner hole is referenced to the screw diameter, and is left in the normal matching gap for processing. Formulated.

4, screw and barrel manufacturing materials

At present, the commonly used materials for screw and barrel manufacturing in China are 45, 40Cr and 38CrMoAlA. The raw materials for the screw and barrel in the imported extruder are 34CrAINi7 and CrMoV9, and the yield strength of the material is about 900MPa. After nitriding treatment, it is both wear-resistant and has good corrosion resistance, and the hardness is above 1000HV.

It is important to note that the extruder screw barrel is two important parts, one is a relatively small and long hole, and the other is a slender threaded rod. The machining and heat treatment processes are complicated, and it is difficult to ensure accuracy. . Therefore, screw and barrel wear repair is not a good choice, and new parts can be replaced. Is it repaired or changed? Must be analyzed from an economic perspective. According to the repair cost is lower than the cost of replacing the new screw, it is not necessarily the correct choice, but it can only be said to evaluate whether it is repaired. It is important to look at the ratio of repair costs to screw time and renewal costs after repair and update screw usage time. A scheme with a small ratio is economical!