1, Precautions for Operators
The operator of the plastic extrusion production line is the main person in charge of maintaining equipment and extending the service life of the extruder. Every operator should understand that reducing the frequency of extruder maintenance, replacing parts, and extending the service life of the extruder is an important measure to reduce the cost of producing plastic products and improve economic benefits. The ability of equipment to operate in optimal conditions for a long time, as well as the stability of plastic quality and production, are the basic conditions for ensuring high profits for production enterprises. The operator can work diligently and responsibly according to the equipment operating procedures, which is the best maintenance and upkeep of the equipment. So before new workers start working, they must learn and memorize the operating procedures of the extruder, and only after passing the actual operation assessment they can officially start working and operate independently. To work independently and become a qualified operator, the following precautions should be taken:
(1). During shift handover, any issues with the production equipment during this shift should be clearly handed over; Make handover records of the production volume, product quality, and production tools for this shift.
(2). When taking over the shift, the first thing to check is the production quality of the product, the quality of the raw materials used in production, and the amount of materials used in the extruder hopper. If any problems are found, they should be promptly reported to the person in charge.
(3). Check whether the extruder barrel and process control temperature are within the production required process temperature range. According to the quality of the product and one's own operating experience, adjustments can be made appropriately.
(4). Inspect the production equipment for one week, check the working condition of each transmission component during equipment operation, check whether the rotation is smooth and normal, listen for abnormal working sounds, and check whether the temperature of the heating part is working properly.
(5). Check the voltage and current pointer of the main motor on the operation control box, and the ammeter pointer should be within the normal rated current index.
(6). Production is normal. The extruder screw rotates smoothly, and plastic products are extruded from the machine head at a uniform speed and smoothly; At intervals, take a look at the appearance quality of the product or take some products to test whether all indicators of the product are qualified.
(7). When encountering a sudden power outage at work, the main motor, electric heating, and feeding system switches should be immediately turned off, and the speed control switch knobs should be adjusted back to zero. When restoring power, the machine barrel should be heated and warmed up first. After reaching the process temperature, it should be kept at a constant temperature for a period of time; Rotate the motor connection belt by hand and test the resistance of the screw rotation; If it's easier, you can start the motor at low speed and start working. If the ammeter pointer exceeds the rated current value or the screw starts at an unstable speed, it should be stopped in a timely manner, the cause should be investigated (possibly due to the low temperature of the material inside the barrel), the cause of the fault should be investigated and eliminated before starting up.
(8).If the shutdown time is long or the production is stopped, there is no need to clean the cylinder if it is made of polyethylene glycol raw materials. If there are raw materials such as polyamide inside the barrel, it is necessary to clean the raw materials inside the barrel; After cleaning the residue inside the screw machine barrel, apply a layer of rust proof oil, wrap the screw, and hang it vertically in a dry and ventilated place
2, Daily and regular maintenance
(1). Daily maintenance is a routine work that does not take up equipment operating hours and is usually completed during driving. The main task is to clean the various components of the extruder and check for any damage or wear regularly. Especially, it is necessary to clean and replace the screws to ensure the smooth operation of the extruder regularly. Lubrication of various moving parts, such as gearboxes, bearings, oil pumps, etc.Check the operation status of these lubrication components and add an appropriate amount of lubricating oil as needed to ensure the normal operation of the extruder. Tighten easily loose threaded parts,inspect and adjust the motor, control instruments, various working components,pipelines and etc timely .
(2). Regular maintenance is usually carried out after the extruder has been running continuously for 2500-5000 hours and then stopped. The machine needs to be disassembled for inspection, measurement, and identification of the wear of major components, replacing parts that have reached the specified wear limit, and repairing damaged parts. Check the output, temperature control accuracy, and pressure sensor of the extruder, as well as check for any odor or alarm sounds around the equipment, to ensure that the extruder is within its normal operating range.
(3). When plastic extrusion equipment needs to be stopped for a long time, anti rust lubricating grease should be applied to the working surfaces of screws, machine blades, machine heads, etc. Small screws should be suspended in the air or placed in wooden boxes, and leveled with wooden blocks to prevent deformation or damage to the screws.
(4). If there is any abnormal noise during the operation of the extruder, it should be stopped immediately for inspection or repair.
(5). Pay attention to the cleanliness of the production environment, and do not let garbage and impurities mix into the material to block the filter plate, which will affect the output and quality of the product and increase the resistance of the machine head.
(6). The maintenance of the gearbox for plastic extrusion equipment is the same as that of a general standard gearbox. The main task is to inspect the wear and failure of gears, bearings, and other components. The gearbox should use the lubricating oil specified in the machine manual, and add oil according to the specified oil level height. If the oil level is too low, the lubrication will not be reversed, which will reduce the service life of the parts; Excessive oil, high heat generation, high energy consumption, and easy deterioration of oil can also cause lubrication failure and result in damage to parts. The oil leakage part of the gearbox should replace the sealing gasket timely manner to make sure the amount of lubricating oil.
(7). Strictly prevent metal or other debris from falling into the hopper to prevent damage to the screw and barrel. To prevent iron debris from entering the barrel, magnetic components or magnetic racks can be installed at the feeding port of the barrel to prevent debris from falling. The material needs to be screened beforehand.
(8). When removing residues from the barrel, screw, and mold, only bamboo or copper knives can be used to scrape the adhesive material. Steel knives are not allowed to scrape the adhesive material, and it is also not allowed to remove residues from the screw by fire grilling methods
(9). The inner wall of the cooling water pipe attached to the plastic extrusion equipment is prone to scaling, while the outer wall is prone to corrosion and rust. Careful inspection should be carried out during maintenance. Excessive scale can clog the pipeline, fail to achieve cooling effect, and severe rust can cause water leakage. Therefore, measures such as descaling and anti-corrosion cooling should be taken during maintenance.
(10). Empty operation is not allowed to prevent screw and machine from becoming rough. When the host starts idling, it is not allowed to exceed 100r/min.
(11). For DC motors that drive screw rotation, the main inspection is to check the wear and contact of the brushes, and the insulation resistance value of the motor should also be regularly measured to ensure it is above the specified value. In addition,check the connecting wires and other components,if they are rusted, and take protective measures.
(12). Calibrate temperature control instruments regularly, check the correctness of adjustment and effectiveness of control.
From the above introduction, we can see that maintenance of plastic extruders is very necessary. Only continuous maintenance and upkeep can ensure the normal use of the extruder and extend its service life. Therefore, for users, it is very important to maintain the extruder well, and it is also one of the effective measures to reduce production costs and improve product quality.