1. Abnormal noise
(1) If it occurs in the reducer, it may be caused by bearing damage or poor lubrication, or it may be caused by gear wear, improper installation and adjustment, or poor meshing. It can be solved by replacing bearings, improving lubrication, replacing gears, or adjusting gear meshing conditions.
(2) If the noise is a sharp scraping sound, consider the possibility of the shaft head and the drive shaft sleeve scraping due to the deflection of the barrel position. It can be solved by adjusting the barrel.
(3) If the barrel makes noise, it may be because the screw is bent to sweep the bore or the set temperature is too low, causing excessive friction of solid particles. It can be processed by straightening the screw or increasing the set temperature.
2. Abnormal vibration
If this happens at the reducer, it is caused by the wear of the bearings and gears, which can be solved by replacing the bearings or gears; if it happens at the barrel, it is due to the hard foreign matter mixed in the material, and the cleaning of the material needs to be checked.
3. The main cause of wear of screw extruder
The normal wear of the screw and barrel of the screw extruder mainly occurs in the feeding area and the metering area. The main cause of wear is caused by the dry friction between the chip particles and the metal surface. When the chip heats up and softens, the abrasion decreases.
Abnormal wear of the screw and barrel will occur when the screw is locked by ring knots and foreign objects. Ring knot means that the screw is locked by the condensed material. If the screw extruder lacks a good protective device, the powerful driving force may be twisted. If the screw is stuck, it will produce unusually huge resistance, causing serious damage to the surface of the screw and severe scratches on the barrel. The scratches on the barrel are difficult to repair. In principle, the service life of the barrel is longer than that of the screw. For the normal wear and tear of the barrel, it is generally not repaired. The method of repairing the screw thread is often used to restore the radial gap between the inner hole of the barrel and the outer diameter of the screw.
4. Solution to screw wear
The local damage of the screw thread is repaired by surfacing welding of special anti-wear and corrosion-resistant alloy. Generally, inert gas shielded welding and plasma argon arc welding are used. Metal spraying technology can also be used for repair. First, grind the outer surface of the worn screw to a depth of about 1.5 mm, and then surfacing the alloy layer to a sufficient size.
The machining allowance of is the original size after grinding the outer circle of the screw and the side of the screw thread to the outer dimension of the screw.
5. Annular blockage at the screw entrance
This kind of failure is mainly caused by the cooling water cut-off or insufficient flow. It is necessary to check the cooling system and adjust the cooling water flow and pressure to the specified requirements.