How to Maintain Screw Extruder barrels?

Maintenance is crucial for mechanical items, and the screw cylinder is one that requires frequent care. The working quality of the combination of the screw and cylinder components significantly impacts the plasticization of materials, the quality of products, and production efficiency. Their performance is related to the manufacturing precision of the cylinder screw and the assembly clearance. When the screw cylinder is severely worn and the output of plastic machinery declines, it's time to schedule maintenance for the screws and cylinders. Today, let's discuss several maintenance methods for the screw cylinder.

· If the machine is shut down for more than half an hour, it is recommended to close the feeding mouth, clean the material inside the hopper, and set the temperature to maintain heat.

·Prevent screw shaft from rotating in vain or slipping.

· Avoid mixing POM and PVC in the hopper simultaneously, as a reaction may occur at melting temperatures, leading to severe industrial accidents.

· When using new plastics, clean the excess material from the barrel thoroughly. Minimize material degradation when using materials like POM, PVC, and PA+GF, and promptly flush the barrel clean with water-shut materials like ABS after shutdown.

· When the temperature of the molten plastic is normal yet black spots or discoloration is continually found, it should be checked whether the reverse stopper seat of the胶螺杆(gasket, spacer) is damaged.

· Do not start the machine if the barrel has not reached the preset temperature. For newly opened electric heaters, it is generally required to wait 30 minutes after the temperature reaches the set value before operating the screw.

· Ensure that the plastic in the hopper is fully melted when using the anti-splash device to prevent damage to the transmission system components when the screw retracts.

· Avoid foreign objects falling into the hopper to damage the screw and hopper. Prevent metal fragments and debris from entering the bin; if processing recycled material, use a magnetic bin to prevent iron shavings and other debris from entering the hopper.

· After removing the screw from the barrel, take advantage of the remaining heat in the barrel to clean it with a cloth roll when the residue materials are soft. Shine a light to inspect for any abnormal scratches or abrasions on the inner wall of the barrel. Measure the inner diameter of the barrel for any changes, comparing it to the dimensions before and after use, to assess wear. Subsequently, check for any damage to other parts of the barrel. Once the screw barrel is clean, apply oil to prevent rust.

· Clean or replace the rubber tip, remove it and burn it to thoroughly burn off any excess material from the tip.

· When using new plastic, ensure the excess material in the extruder barrel is thoroughly cleaned. Minimize degradation of materials like POM, PVC by reducing exposure, and promptly clean with water nozzle materials such as ABS after shutdown.

· The disassembly of a screw thread typically involves pushing the screw out from the rear or removing it with a specialized tool.

· After cleaning the screw and its connected parts, inspect the working surfaces for scratches and friction damage. For minor scratches, use fine sandpaper or an oilstone for smoothing.

· When the working surface of the screw shows severe wear and the groove is quite deep, the cause of the damage should be analyzed and cleared, the fault should be rectified, to prevent recurrence of similar issues, and then the worn groove should be treated. If both the screw and the barrel are heavily worn, first measure the actual clearance between the two components. If it exceeds the standard by a significant margin, it is time to replace the screw.

· When assembling the screw, apply a layer of molybdenum disulfide heat-resistant grease to the mating surface of the other parts for easy disassembly next time.

· Idle screws should be coated with protective oil after surface cleaning, wrapped, and hung in a dry and well-ventilated area.

· Screws should be manufactured from alloy steel that is wear-resistant and minimally deformed at high temperatures. The working surface of the screw after precision processing should be both wear and corrosion-resistant, thus the threaded portion of the screw should be nitrided and coated with hard chrome, achieving a hardness of HV940-1100.