Introduction
Cutting fluid is an important criterion for selecting machining methods and ensuring the quality and stability of the machining process and product quality. Selection and application of cutting fluid is the object of research in many industrial disciplines. Along with the rapid development of science and technology, cutting fluid is accompanied by higher demands in technological level and performance requirements. The selection and application of cutting fluid is mainly depend on the material and machining conditions of the workpiece as well as the manufacturing requirements.
Types of Cutting Fluids
Cutting fluid is a kind of fluid that is used in the cutting and grinding process for cooling, lubrication and chip control in the machining process. It is an effective means of avoiding excessive wear, surface damage and cratering of the cutting tools. The following are the main types of cutting fluids commonly used in machining:
1. Soluble oil cutting fluids: dissolve fatty acid oil in water and form a true solution. The main components are emulsifier, fattening agent, anti-rust agent and antifoaming agent. It has the characteristics of low viscosity, low friction coefficient and good rust resistance.
2. Semi-synthetic cutting fluid: It is composed of neat oil or mineral oil and 15-20% substance of alcohol ester or other synthetic oil, and carbohydrate or soap paste as a stabilizer. The main components are emulsifier, antioxidant, antifoaming agent and coupling agent. It has the characteristics of high lubricity and good cooling ability.
3. Synthetic cutting fluid: It is made of synthetic oil such as phosphate ester, silicones, fluorine compounds and boron compounds, and more than one organic or inorganic surface active agent, anti rust agent and anti foaming agent. It has excellent lubrication and cooling effect, but is also more expensive than other types of cutting fluids.
Selection Principles of Cutting Fluids
1.The cutting fluid should be in good condition and have good heat dissipation performance, because the heat generated at the cutting interface will make the chip move up and down and cause vibration of the cutting tool and workpiece, affecting the machining quality.
2. The cutting fluid should have good lubricity, low coefficient of friction, low coefficient of adhesion and good cooling performance, in order to reduce the tool wear and the cutting temperature.
3. The cutting fluid should have good anti-corrosion performance to protect the cutting tool and workpiece during machining.
4. The cutting fluid should have good detergency to flush away the chips generated at the machining surface and clean the cavities.
5. The cutting fluid should have good biocompatibility, so as to protect the operators health.
Application of Cutting Fluids
The cutting fluid should match the cutting tools, workpiece material and machining conditions. It is necessary to select the appropriate cutting fluid according to different working environment compounds, cutting speed, cutting depth, cutting temperature, time and other working conditions.
1. Turning machining: dry cutting, cutting fluid cutting and high pressure cutting fluid cutting. Dry cutting is suitable for low cutting hardness and small cutting depth, and can reduce the cost; cutting fluid cutting is suitable for high cutting hardness and high cutting speed, and can reduce the cutting temperature and reduce the cutting force; high pressure cutting fluid cutting is used for deep hole and internal thread cutting, which not only reduces the cutting temperature, but also maintains good machining precision.
2. Milling machining: suitable for dry cutting, cutting fluid cutting and high pressure cutting fluid cutting. Dry cutting is suitable for low cutting hardness and small cutting depth, and can reduce the cost; cutting oil cutting is suitable for high cutting hardness and large feed and depth, which can reduce cutting temperature, tool wear and improve processing efficiency; high pressure cutting fluid cutting is suitable for deep hole, inner end face and internal thread cutting, which can reduce cutting temperature, reduce vibration and improve processing precision.
3. Planing machining: suitable for dry cutting, cutting fluid cutting and high pressure cutting fluid cutting. Dry cutting is suitable for low cutting hardness and small cutting depth, which can reduce the cost; cutting fluid cutting is suitable for high cutting hardness and large feed and depth, which can reduce cutting temperature, tool wear and improve machining efficiency; high pressure cutting fluid cutting is suitable for deep hole and inner end face machining, which can reduce cutting temperature and improve processing precision.
4. Drilling: suitable for dry cutting, cutting oil, neat oil, high pressure cutting fluid and cutting paste. Dry cutting is suitable for low cutting hardness, small cutting depth and short hole, which reduces cost; cutting oil is suitable for high cutting hardness, large cutting depth and deep hole, which has good cooling performance and high service life; neat oil is suitable for high cutting hardness, large cutting depth, large diameter and internal thread drilling, which can reduce cutting temperature and improve machining precision; high pressure cutting fluid is suitable for large depth and large inner end face holes and internal thread drilling, which can reduce cutting temperature and improve processing precision.
5. Boring: suitable for dry cutting, cutting fluid cutting and high pressure cutting fluid cutting. Dry cutting is suitable for low cutting hardness and small cutting depth, which can reduce the cost; cutting fluid cutting is suitable for high cutting hardness and large feed and depth, which can reduce cutting temperature, tool wear and improve machining efficiency; high pressure cutting fluid cutting is suitable for deep hole and inner end face machining, which can reduce cutting temperature and improve processing precision.
Conclusion
The selection and application of cutting fluids is very important for machining process. To determine suitable cutting fluids is based on the workpiece material and machining conditions. It is necessary to select the appropriate cutting fluids according to different working environment compounds, cutting speed, cutting depth, cutting temperature, etc. Cutting fluid not only can reduce the cutting temperature, but also can reduce the cutting force. Besides, it also has the effect of rust prevention and chip removal. Therefore, in order to ensure the quality of workpiece and improve machining efficiency, it is necessary to select and use cutting fluids correctly.
