In order to extend the service life of the tool, it is necessary to select a reasonable type of metalworking fluid and optimize the processing method, especially for difficult-to-process materials. When cutting difficult-to-machine materials, high-quality cutting fluid is required, and the cost of this cutting fluid is also relatively expensive. However, in the cutting process, difficult-to-machine materials often have an adverse effect on the service life of the tool. Therefore, it is very necessary to choose a suitable cutting fluid to effectively extend the service life of the tool and reduce the processing cost. The direct cause of tool damage is cutting force and cutting heat. Therefore, no matter which processing method is used, the fundamental purpose is to minimize the temperature of the tool tip of the cutting part and the processed area of the part, and prevent the surface hardening of the processed part. And the temperature of the tool tip is too high to increase the heat dissipation area and control the cutting force.
Solution:
1. Properly control the cutting force and cutting speed
Properly controlling the cutting force and cutting speed of the tool is also one of the most effective means to reduce the temperature of the processing area and extend the service life of the cutting fluid. When processing difficult-to-machine materials, the cutting edge is generally finely ground, and the cutting depth and cutting width should not be too large. When selecting the cutting linear speed, it is necessary to consider factors such as different material types, part structures and processing equipment. In general, if the processing material is a nickel-based alloy, the line speed should be controlled at 20 to 50 meters per minute; the processing material is titanium alloy, and the line speed should be controlled at 30 to 110 meters per minute; the processing material is PH stainless steel, and the line speed It should be controlled within the range of 50 to 120 meters per minute.
2. Choose a reasonable cutting method
For difficult-to-machine materials, choosing different cutting methods has great differences in the damage of cutting fluid. No matter which cutting method you choose, the principle is the same, that is, to reduce the cutting force and temperature in the cutting zone as much as possible. Cycloidal cutting method can minimize the cutting area and minimize the actual cutting angle of cutting fluid, thereby prolonging the heat dissipation time of each tooth of the tool and reducing the cutting temperature; the spiral interpolation method can make the cutting amount of each tooth relatively uniform , To avoid the cutting force concentrated on a few teeth and accelerate the wear, this effect is most obvious at the corners; and the high-feed cutting method is adopted to effectively reduce the cutting with a smaller depth of cut and a larger feed. Force, so that the smallest cutting heat is generated during processing, and the processing area has the lowest temperature.
3. Ensure timely and effective chip breaking
In metal processing, a large amount of cutting heat is generally generated on the cutting chips. If the length of the chip can be controlled to ensure timely and effective chip breaking, this part of the cutting heat can be taken away by the chips. Therefore, the chip breaking is to control the cutting temperature. An effective way. When processing difficult-to-process materials, especially in the roughing process, under the premise that the rigidity of the processing system allows, try to make it break the chips during the entire processing process. At the same time, use a cutting fluid with good sedimentation performance to settle and discharge the cutting chips, and do not let the cutting chips rub against the surface of the machined workpiece.
4. Choose the right cutting fluid
Different cutting fluids should be selected according to the requirements of machining conditions and machining accuracy. For high-speed machining, a large amount of heat can be generated, such as high-speed cutting, drilling, etc. If the generated heat cannot be taken away by the cutting fluid in time, the phenomenon of tool sticking will occur, and the built-up edge will be severely affected. The machining roughness of the workpiece and the service life of the tool, and the heat can also deform the workpiece, which seriously affects the accuracy of the workpiece. Therefore, the choice of cutting fluid must take into account its own lubricity and cooling performance. For finishing, it is easy to choose emulsified antifriction cutting fluid or low-viscosity cutting oil. For semi-finishing and roughing, you can choose low concentration. Emulsified anti-friction cutting fluid or semi-synthetic anti-friction cutting fluid with good cooling performance.
For the grinding process, the grinding chips are very small, and a lot of heat will be generated during the grinding process. Therefore, when choosing a cutting fluid, it is necessary to consider not only the lubrication and cooling performance, but also the filterability of the cutting fluid. If the selected cutting viscosity is too large, the chips cannot be deposited or filtered out in time, then the surface of the workpiece will be scratched as the cutting fluid circulates to the processing area and the finish of the processed surface will be affected. Therefore, it is easy to choose low-viscosity anti-friction grinding oil or semi-synthetic anti-friction cutting fluid for fine grinding or super-finishing, and low-concentration semi-synthetic cutting fluid or fully synthetic cutting fluid for semi-finishing or rough grinding.
In the selection of cutting fluid, in addition to the performance of the cutting fluid's lubricity and cooling, the performance of the cutting fluid's rust resistance, cost and easy maintenance should also be considered. The cutting oil is easy to choose a base oil with a relatively low viscosity to add anti-friction additives, so that it can achieve lubrication and anti-friction, but also has good cooling and easy filtering. However, the problem of cutting oil is its low flash point, heavy smoke during high-speed cutting, low flash point, high risk factor, and fast volatilization, the user's use cost is correspondingly higher, so try to use water-soluble when conditions permit Cutting fluid.
For water-based cutting fluids, it is more important to consider its rust resistance. Nowadays, the commonly used water-based aluminum rust inhibitors include silicate and phosphate grease. For workpieces that have been stored for a long time between procedures, it is easy to use cutting fluids with phosphate grease type rust inhibitors during processing.
