The barrel wear of the plastic extruder is mainly manifested in the wear and tear during use, which leads to the increase of the barrel inner diameter. Since the inner surface hardness of the barrel is higher than that of the screw, the barrel is damaged later than the screw. The barrel maintenance method and the following matters should be noted during maintenance:

1. Due to wear, the diameter of the cylinder increases. If there is a nitriding layer, the hole in the cylinder can be directly ground to obtain a new diameter size, and then a new screw is prepared according to the new diameter.

Through machining, the inner diameter of the barrel is trimmed, the alloy is recast, the thickness is controlled at 1~2mm, and then fine-machined to the required new size.

3. Under normal circumstances, the barrel homogenization section wears faster than other positions. The boring of the homogenization section can be trimmed and then equipped with a nitrided alloy steel bushing. The inner hole diameter refers to the screw diameter, and the normal matching clearance is left for processing and preparation.

4. Screw and barrel manufacturing materials.

At present, the commonly used screw and barrel materials in China are 45, 40cr and 38crMoAlA, while the manufacturing materials of screw and barrel in imported extruders are 34crAINi7 and crMoV9, and the material yield strength is about 900mpa. After nitriding treatment, it has good wear resistance, good corrosion resistance, and hardness above 1000HV.

It should be noted that the extruder screw barrel is two important parts, one is a threaded rod with a smaller diameter, a longer hole, and a finer hole, and its machining and heat treatment process are more complicated. Therefore, it is not a good choice to repair the wear of the screw and barrel, and it can also be replaced with a new one. Repair or replace? It should be analyzed from an economic point of view. It is not the right choice to determine the repair based on the cost of repair being lower than the cost of replacing a new screw, but it can only be said to be one aspect of evaluating whether to repair. It is important to look at the ratio of the cost of repair and the time of using the screw after repair to the cost of renewal and the time of using the renewed screw. The solution with a small ratio is economical!