Periodic lubrication of machine tools is of great significance, because lack of lubrication or poor lubrication will lead to machine tool, bearing and other components to find acceleration wear and even cause machine tool failure. Therefore, it is very important to choose the most suitable lubrication oil and lubrication point in oper
In general, the lubrication oil used in machine tools must have the following properties:
1. Good corrosion resistance. It can prevent corrosion from various kinds of working environment, thus prolonging the service life of machine tools and other components.
2. Good oxidation stability. Many oil components are liable to be oxidized and decomposed by air and water vapor, which will produce sludge, so the oil must have strong oxidation stability.
3. Good viscosity stability. The viscosity of oil should remain relatively unchanged over a wide range of temperature, this requires that the oil has good oxidation stability, but also has good thermal cracking resistance.
4. Good anti-foaming and air release performance. Generally, the oil film is easy to produce foam, which not only affects lubrication effect, but also reduce the life of machine tools and other components. Air release ability of oil is the key.
5. Good anti-rust and anti-wear performance. In the mixed operation of small particles, large or small metal particles or grinding powder, if there is no anti-rust and anti-wear property of the oil, it is easy to cause wear of machine tool and other components. Therefore, the anti-rust and anti-wear performance of the lubricating oil is very important.
6. Good cleaning performance. The metal powder and grinding powder mixed in the oil during the operation will cause metal corrosion and the accumulation of loose dirt in the machine tools, which requires that the lubricating oil must have good cleaning performance.
In addition, the lubricating oil used in machine tools must also have high flash point and low pour point, so as to avoid the low temperature embrittlement of the lubricating oil and ensure operation safety.
In general, there are several types of lubricating oil that can be used for machine tool lubrication, including lubricating oil for mechanical parts, guide rails and ball screws; hydraulic oil for hydraulic CNC system; cutting oil for machining, etc.
For machine tool parts, mechanical parts and guides, the most suitable lubricant is mechanical lubricating oil. To a certain extent, grease is also used. According to the compositions, special mechanical lubricating oils are divided into mineral oil, synthetic oil and semi-synthetic oil. Which one should be used depends on its application conditions, such as working temperature, pressure and load size.
Synthetic oil has good oxidation stability, low viscosity change and excellent anti-wear properties, so its service life is long, generally up to four times of mineral oil. Synthetic oil is suitable for low temperature and high load heavy load lubrication. However, because synthetic oil is expensive, it is not economical to use when the pressure and load are relatively low.
In the operation of CNC machine tools, if they are still using droplet lubrication and manual lubrication, the oil can be selected according to environmental conditions, temperature, number of lubrication points, lubrication interval, etc. When the number of lubrication points is small and the lubrication interval is long, it is recommended to use anti-wear grease or semi-fluid lubricating oil.
For hydraulic system of CNC machine tools, hydraulic oil is selected as lubricant. Because hydraulic lubrication system is relatively closed, rarely influenced by external factors, this kind of oil requires excellent oxidation stability, anti-rust and anti-emulsification performance, and excellent air release performance. The viscosity of this kind of oil is usually 22-68cst.
In addition, for machining of high precision and small tolerance, cutting oil needs to be selected. The quality of cutting oil directly affects the machining quality, the cutting force and feed. If the cutting oil is not suitable, it is easy to cause chip failure, burr, poor quality, etc. Cutting oil is generally composed of special mineral oil and multiple additives, and its viscosity is generally 15-85mm2/s.
In conclusion, the choice of lubricants should be based on the type, size and speed of the machine tool, as well as the structure, function and operation environment of the machine tool. In order to ensure the normal work of the machine tool and prolong the service life, it is necessary to choose the lubricant strictly according to the environmental requirements and performance requirements.
