Maintenance of Extruder Screw

Ⅰ. Selection and installation of extruder screw

1. The extruder screw should be made of alloy steel with wear resistance and small deformation when working in a high temperature environment. After finishing, the working surface of the extruder screw should be wear-resistant and anti-corrosion, so the screw thread part should be nitrided and plated with hard chromium layer. The hardness is 700-800HV.

2. When idling the test machine, pay attention that the extruder screw cannot run idly for a long time. During the commissioning of the test machine, the idling time should exceed 3 minutes.

3. After the extruder screw and its connected parts are cleaned, check whether there are scratches and friction damage on each working surface. If there are minor scratches, use a fine emery cloth or whetstone to repair.

4. When assembling the extruder screw, the joint surface with other parts should be coated with a layer of molybdenum disulfide heat-resistant grease to facilitate the next disassembly.

5. To dismantle the extruder screw, generally the extruder screw can be ejected from the rear or pulled out with a tool.

Ⅱ. Daily maintenance of extruder screw

1. The daily maintenance of the extruder screw is a regular routine work, which does not occupy the operating hours of the equipment and is usually completed during the start-up period. The key is to clean the machine, lubricate the moving parts, tighten the loose threaded parts, check and adjust the motor, control instruments, working parts and pipelines in time.

2. Regular maintenance of the extruder screw is generally carried out after the extruder runs continuously for 2500-5000h. Machines need to be dismantled to check, measure and identify wear on major components. Replace parts that have reached the specified wear limit and repair damaged parts.

3. The extruder screw is not allowed to run empty, so as to prevent the screw and barrel from rolling.

4. Strictly prevent metal or other sundries from falling into the hopper of the extruder screw, so as not to damage the screw and barrel. In order to prevent iron debris from entering the barrel, magnetic parts or a magnetic frame can be installed at the feeding port of the barrel to prevent debris from falling. The materials must be screened in advance.

5. Pay attention to the clean production environment of the extruder screw. Do not mix garbage and impurities into the material, which will block the filter plate, affect the output and quality of the product and increase the resistance of the machine head.

6. When the extruder needs to be stopped for a long time, anti-rust grease should be applied to the working surfaces of the extruder screw, barrel, head and so on. The small screw should be suspended in the air or placed in a wooden box. It should be leveled with a wooden block to prevent the screw from being deformed or bruised.

Ⅲ. Repair of extruder screw

1. If an abnormal sound occurs when the extruder screw is running, it should be stopped immediately for inspection or repair.

2. When the working surface of the extruder screw is severely worn and the scar groove is deep, the cause of the damage should be analyzed and the fault should be eliminated to avoid the recurrence of similar phenomena. Then the worn scars should be dealed with. If both the screw and the barrel are severely worn, the actual fit clearance of the two parts should be checked first. If it exceeds the standard by a lot, the extruder screw should be replaced at this time.

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