The local damage of screw thread is repaired by surfacing special wear and corrosion resistant alloy. Inert gas shielded welding and plasma argon arc welding are generally used. Metal spraying technology can also be used for repair. Firstly, grind the worn cylindrical surface of the screw to a depth of about 1.5 mm, and then weld the alloy layer to a sufficient size to ensure sufficient strength
Finally, grind the outer circle of the screw and the side of the thread to the overall dimension of the screw as the original dimension.
2.3 ring blocking material at screw inlet（extruder)
This fault is mainly caused by the cut-off or insufficient flow of cooling water. It is necessary to check the cooling system and adjust the cooling water flow and pressure to the specified requirements.
conclusion
(1) The natural service life of extruder is long, and its service life mainly depends on the wear of machine Jane and reduction gearbox. The extruder and reducer with excellent design, material selection and manufacturing are directly closed
Considering the service performance, although the equipment investment increases, the service life is prolonged. Considering the overall economic benefits, it is more reasonable.
(2) The normal use of screw extruder can give full play to the efficiency of the machine and maintain a good working state. Unremitting and careful maintenance is required to prolong the service life of the machine.
(3) The main faults of screw extruder are abnormal wear, foreign matter jamming, link blocking, wear or damage of transmission parts, poor lubrication or oil leakage, etc. In order to avoid failure, the drying, mixing and feeding operations and the setting of process temperature must be strictly managed, and daily maintenance, maintenance and overhaul must be carried out in strict accordance with the requirements of equipment point patrol inspection benchmark.