One, choose according to the tool material
1. Tool steel knives:
It has poor heat resistance and requires good cooling effect. It is better to choose emulsion.
2. High-speed steel tools:
The highest temperature can reach 600°C. When cutting at low and medium speeds, use oil-based cutting fluid or emulsion. In high-speed cutting, water-based cutting fluid is appropriate due to the large heat generation
3. Cemented carbide tools:
The maximum allowable working temperature can reach 1000℃, and the oil-based cutting fluid containing anti-wear additives is selected. Attention should be paid to cooling the tool uniformly. Before cutting, the tool should be cooled with cutting fluid in advance. For high-speed cutting, a large flow of cutting oil should be used to spray the cutting area to reduce uneven heating of the tool and chipping, and also to reduce oil smoke.
4. Ceramic knives:
High temperature wear resistance is the highest, generally dry cutting is used, water-based cutting fluid can also be used.
5. Diamond tool:
With extremely high hardness, dry cutting is generally used. In order to avoid excessive temperature, water-based cutting fluid is also used like ceramic materials.
Second, the selection and maintenance of aluminum alloy cutting fluid
1. Features of aluminum and aluminum alloys
1) Aluminum and aluminum alloys are soft and plastic, deform large during cutting, and are easy to stick to the tool, forming a built-up edge on the tool, which may cause melting and welding, which will cause the tool to lose its cutting ability, and affect the machining accuracy and surface roughness.
2) The thermal expansion coefficient of aluminum alloy is large, and the heat of cutting is likely to cause thermal deformation at work and reduce machining accuracy.
3) The surface is prone to discoloration and pitting corrosion, and the surface brown becomes black, and white powder will be precipitated, commonly known as white rust.
2. Selection of aluminum alloy cutting fluid
Both lubricity and cooling performance should be taken into consideration, and emulsified cutting fluid or low-viscosity cutting fluid should be selected for finishing.
3. Aluminum alloy grinding
Since the grinding is very small, the filterability of the cutting fluid should be paid attention to. Do not choose a grinding fluid that is too thick, otherwise the chips will not be deposited or filtered out in time, which will scratch the surface of the workpiece and affect the surface finish. Therefore, it is easy to choose precision grinding oil or semi-synthetic cutting fluid for fine grinding or super fine grinding.
4. Use and maintenance of aluminum alloy cutting fluid
1) Use tap water, preferably deionized water, to ensure the effectiveness and service life of the cutting fluid.
2) The machine tool must have a filter system, and the filter or non-woven fabric should be cleaned at least once every 3 days. Because aluminum alloy is prone to produce aluminum soap, it will destroy the stability of the cutting fluid. The aluminum chips should be filtered out immediately to prevent the aluminum chips from reacting with the cutting fluid and affecting the effect and life. During the grinding process, the aluminum chips are both small and light, and it is difficult to settle down. If the filtering is not performed or the filtering is not sufficient, the aluminum chips will scratch the machined surface and affect the surface gloss.
3) Ph value. Aluminum material is very sensitive to the Ph value of cutting fluid. It is necessary to check the Ph value of cutting fluid frequently. If abnormalities are found, adjust the Ph value in time to control the Ph value between 8-9 to avoid excessively high Ph value corroding the workpiece. Too low makes the bacteria multiply and affects the stability and performance of the cutting fluid.
4) Add new liquid regularly. That is to ensure the good lubrication of the cutting fluid, but also to ensure the good rust resistance, sterilization and corrosion resistance of the cutting fluid, so as to extend the service life of the working fluid.
5) Pay attention to the method of preparing new liquid, when to add diluent, and the method of in-depth management.