Lubrication characteristics and application skills of metal cutting machine tools

Metal cutting machine tools (referred to as machine tools) are equipment with a large quantity and a wide range of varieties. Their structural characteristics, machining accuracy, automation degree, working conditions and environmental conditions are very different, and the lubrication system and the lubricant used are different. Requirements.
1. Features and requirements of machine tool lubrication:

1. The main parts and components in the machine tool are mostly typical mechanical parts, which are standardized, universal, and highly serialized. For example, sliding bearings, rolling bearings, gears, worm gear pairs, rolling and sliding guides, screw transmission pairs (screw nut pairs), clutches, hydraulic systems, cams, etc., have different lubrication conditions.

2. The environmental conditions of the machine tool: The machine tool is usually installed in an indoor environment. The maximum ambient temperature in summer is 40℃. When the temperature is lower than 0℃ in winter, heating methods are used to make the ambient temperature higher than 5-10℃. High-precision machine tools require a constant temperature air-conditioning environment, generally around 20°C. However, due to the high precision and automation requirements of many machine tools, the requirements on the viscosity, oxidation resistance (service life) and cleanliness of the oil are stricter.

3. The working conditions of the machine tool: different types of machine tools with different specifications and sizes, even on the same machine tool, due to the different conditions of the machined parts, the working conditions are very different. The requirements for lubrication are different. For example, the grinding wheel spindle bearings of high-speed internal grinders have very different requirements for lubrication methods and lubricants from the heavy-duty and low-speed spindle bearings of heavy-duty machine tools. The former needs to be lubricated with oil mist or oil/gas lubrication system, using lower viscosity lubricating oil, while the latter needs to be lubricated with oil bath or pressure circulation lubrication system, using higher viscosity oil.

4. The adaptability of lubricating oil to lubricating coolant, rubber seals, paint materials, etc.: Lubricating coolant is used on most machine tools. In the lubricating oil, the oil is often emulsified and deteriorated due to the mixing of coolant. The rust of the machine parts will cause the rubber seals to expand and deform, causing bubbles and peeling of the paint coating on the surface of the parts. Therefore, consider the adaptability of oil and lubricating coolant, rubber seals, paint materials, and preventing oil leakage. Especially with the improvement of the degree of automation of machine tools, common lubrication/cooling oils are used in some automation and numerical control machine tools, which can be used as lubricating oil and lubricating coolant.

2. Use skills of machine tool lubricants:

Due to the wide variety of metal cutting machine tools, the structure and component conditions have changed greatly, it is difficult to give clear opinions on the selection of lubricants for their main components. The following content is based on the recommendations of the reasonable application of lubricants for the main components of machine tools. Suggestions for reference when choosing lubricants.

1. Recommended selection of lubricants for machine tools:

Total loss system: refined mineral oil, L-AN32, L-AN68 or L-AN220, used for light-loaded parts, and HL hydraulic oil is often used.

2. Gear (closed gear): continuous lubrication (splash, circulation or spray), refined mineral oil, and improve its oxidation resistance, corrosion resistance (ferrous metals and non-ferrous metals) and foam resistance, CKB32, CKB68 or CKB100 , CKB150, closed gears (related to spindle box bearings, tool feed boxes, carriages, etc.) in light load and small operation, CKB32 and CKB68 can also be used for overflow lubrication of mechanical control clutches, CKB68 can replace AN68. Commonly used HL hydraulic oil for machine tool headstock; refined mineral oil, and improve its oxidation resistance, corrosion resistance (black and non-ferrous metals), foam resistance, extreme pressure and wear resistance, CKC100, CKC150, CKC200, CKC320 , CKC460, any type of closed gears (except hypoid gears) and related bearings that operate at normal or medium constant temperature and under heavy loads, can also be used for manual control and control of lead screws, feed screws and light-load guides Centralized lubrication.

3. Main shaft, bearing and clutch: main shaft, bearing and clutch, refined mineral oil, additives to improve its resistance to corrosion and oxidation, FC2, FC5, FC10, FC22, sliding bearing or rolling bearing and related clutch pressure, oil Bath and oil mist lubrication. In a system with a clutch, due to the risk of corrosion, it is necessary to use products without anti-wear and extreme pressure agents; spindles, bearings, refined mineral oil, and additives to improve its corrosion resistance , Anti-oxidation and anti-wear properties, FD2, FD5, FD10, FD22, pressure, oil bath and oil mist lubrication of sliding bearings or rolling bearings, can also be used for parts that require particularly low oil viscosity, such as precision machinery, hydraulics or hydraulics Lubrication of pneumatic machinery, solenoid valves, oil-air lubricators and hydrostatic bearings.

4. Guide rail: refined mineral oil, and improve its lubricity and stick-slip properties, G68, G100, G150, G220, used for the lubrication of sliding bearings, guide rails, especially suitable for low-speed motion guide rail lubrication, making the guide rail “crawl” “The phenomenon is reduced to a minimum, and it can also be used for lubrication of various sliding parts, such as lead screws, feed screws, cams, ratchets, and intermittent light-load worm gears.

5. Hydraulic system: hydraulic system, refined mineral oil, and improve its anti-rust, anti-oxidation and anti-foaming properties, HL32, HL46, HL68; refined mineral oil, and improve its anti-rust, anti-oxidation, anti-wear and anti-foaming properties HM15, HM32, HM46, HM68, general hydraulic systems including heavy-duty components, and also suitable for lubrication of sliding bearings, rolling bearings and various normal loads and gears (except worm gears and hypoid gears). HM32 and HM68 can Respectively replace CKB32 and CKB68; refined mineral oil, and improve its anti-rust, anti-oxidation, viscosity-temperature and anti-foaming properties, HV22, HV32, HV46, CNC machine tools, in some cases, HV oil can replace HM oil. Hydraulic and rail system, refined mineral oil, and improve its anti-rust, anti-oxidation, anti-wear, anti-foam and stick-slip properties, HG32, HG68, used for sliding bearings, hydraulic rail lubrication system combined machinery to reduce the low speed of the rail The “creeping” phenomenon of downward movement can also be used in a separate rail system if the oil viscosity is appropriate. HG68 can replace G68.

5. Where grease is used: general grease, and improve its anti-oxidation and corrosion resistance, XBA or XEB1, XEB2, XEB3, ordinary rolling bearings, open gears and various parts that need to be greased.

Note: Code description: AN—total loss system oil, CKB—anti-oxidation and anti-rust industrial gear oil, CKC—medium-duty industrial gear oil, FC—bearing oil, FD—FC bearing oil to improve wear resistance, G— Rail oil, HL hydraulic oil, HM hydraulic oil (anti-wear type), HV low-temperature hydraulic oil, HG—hydraulic-rail oil, XBA—anti-oxygen and anti-rust grease, XEB—anti-oxidant, anti-rust and anti-wear grease .