Twin screw parts are a very important component of the twin screw extruder, its operating state will greatly affect the operation of the twin screw extruder, and in so many spare parts, the gearbox is also a relatively critical part, its maintenance method should be in accordance with its wear condition, bearing wear status, lubricating oil cleaning status, and its cleaning and cleaning after installation and so on to carry out maintenance.
Gearbox is a very critical spare part in the operation of twin screw extruder, its operating state will have a great impact on the operation of the extruder, the following introduces the maintenance method of the gearbox of twin screw parts:
1. Check the wear condition of the gearbox
Disassemble the gearbox cover, check the wear and tooth condition of the working surface of the reduction gear of each transmission system, if there is a burr or shallow hemp pit on the toothed face, it can be polished with oil stone; Gears with severe wear should be prepared in advance to purchase spare parts for replacement during the next maintenance; The gearbox part of the main engine of the twin screw extruder should be well ventilated, and the working environment temperature should be within the range of 5-35 °C.
2. Check the wear condition of each bearing
Disassemble the gearbox cover, check the wear and tooth condition of the working surface of the reduction gear of each transmission system, if there is a burr or shallow hemp pit on the toothed face, it can be polished with oil stone; Gears with severe wear should be prepared in advance to purchase spare parts for replacement during the next maintenance; The gearbox part of the main engine of the twin screw extruder should be well ventilated, and the working environment temperature should be within the range of 5-35 °C.
2. Check the wear condition of each bearing
First clean the bearing and check whether the inner and outer sleeves are cracked; Observe the noise level and radial void size of the empty operation, and find no problems. Can add some grease to use again; Pay attention to check the bearing parts of the box frequently, and the oil temperature of the fuel tank of the transmission box should not exceed 70 °C when working.
3. Check the cleanliness of the lubricating oil
Check the lubricating oil in the box, if the oil is mixed with impurities or metal powder, it is necessary to carry out filtration and impurity removal work on the lubricating oil, and then replenish the amount of lubricating oil, and often check the oil quantity of the gear lubricating oil in the box to ensure that the transmission parts in the box have good lubrication; The newly put into use gearbox needs to be replaced after 250h of work, and the oil change time after that depends on the state of the oil, it is recommended to replace it once a year after 4000-8000 hours of operation.
4. Clean up and install it after tidying
After cleaning and checking the parts in the box, install the lid; After adding sufficient grease to each bearing part, replace the new oil seal and tighten the bearing cover. Clean the outside of the gearbox to keep the equipment clean.
Maintenance of extruder screws:
- The twisted screw, to seriously check whether the barrel is seriously damaged, if the barrel can be used again, according to the actual inner diameter of the barrel to fully consider, according to the normal void with the barrel to give the outer diameter deviation of the new screw for manufacturing.
- After the thread surface with the reduced diameter of the wear screw is treated, the wear-resistant alloy is hotly sprayed, and the production is thickened at 2-3 mm, and then ground to the size. This kind of production has technical professional screw barrel manufacturers spraying processing maintenance.
- Overlay welding wear-resistant alloy in the threaded part of the worn screw. Depending on the degree of screw wear, overlay welding is 1-2 mm thick, and then the screw is ground to size. This type of wear-resistant alloy is composed of materials such as C, Cr, Vi, Co, W and B, which increases the wear and corrosion resistance of the screw. Technical professional overlay welding plants have a high cost for this type of processing, except for special requirements of screws, which are generally rarely used.
- The maintenance screw can also be plated with hard chrome on the surface, and chromium is also a wear-resistant and corrosion-resistant metal, but the hard chromium layer is relatively easy to fall off.
The daily maintenance of the twin screw extruder should be regular and on time, not accounting for the operating hours of the machine and equipment, usually carried out during the start-up. The focus is on cleaning the machine, lubricating the moving parts, tightening the threaded parts that are easy to loosen, inspecting and adjusting the motor as soon as possible, controlling the instrument, working parts and pipelines, etc.
