The use of cutting fluid has a great influence on the life of the cutter and the quality of processing, even if the best cutting fluid can't be delivered effectively to the cutting area, it can't play its due role. Therefore, when choose the cutting fluid (such as cutting oil) to be used to lubricate, it should be transported to the area where the oil film can be generated on the friction surface. Instead, the cutting fluid should be close to the cutting edge of the cutter if the selected cutting fluid is mainly cooled, such as water based cutting fluid. Under this condition, pressure is usually used to force the cutting fluid into the cutting area, thus taking away the heat generated by friction and deformation of the cutter, workpiece, and chip. The continuous application of cutting fluid is better than the intermittent application of cutting fluid. The intermittent application of the cutting fluid can produce a heat cycle, resulting in the crack and collapse of hard and brittle tool materials such as carbide cutting tools.
Another benefit of using the cutting fluid correctly is to effectively eliminate the chip, which also contributes to the extension of tool life. If the nozzle of the cutting fluid is properly placed, the cuttings of the milling cutter and the drill can be prevented from being blocked or unlined. For some master pieces of processing, or feed the powerful cutting, grinding, using two or more rows of coolant nozzle, so as to fully cooling, it can improve machining efficiency, ensure the quality of machining.
1. Manual oiling:
A solid or cream lubricant can be applied to a tool or workpiece using a brush or a brush (mainly for thread tapping and die sets). A portable liquid supply device has also been developed recently, which is atomized by pressure and sprayed onto knives and workpieces.
In a machine without a cooling system, if the number of drilling or tapping is small, the method is effective. When two different processes are to be completed on the same machine tool, the oil can be used in conjunction with the overflow cooling system on the machine tool.
2. Overflow method:
The most common method of using cutting fluid is overflow method. The cutting fluid is pumped into the pipe by low pressure pump, and the nozzle is installed in the near cutting area through the valve from the nozzle. The cutting fluid flows through the cutting area and then flows to the different parts of the machine, then collects into the oil pan, and then returns from the oil pan back to the cutting tank for recycling. As a result, the cutting fluid should have sufficient volume to allow the cutting fluid to cool down and make the fine cuttings and grinding particles settle. Depending on the type of processing, the volume of the cutting fluid box is about 20-200l, and the individual processing is larger, such as drilling deep hole and strong grinding, etc., the cutting fluid can reach 500-1000l or larger. A coarse filter should be provided in the oil collecting tray to prevent large cutting into the cutting tank and a fine filter is installed in the suction port of the pump. For grinding, grinding and deep hole drilling, deep hole boring machine, due to the processing of the workpiece surface quality requirement is high, must remove the finer abrasive dust particles, grinding wheel and the cutting particles, such as gun drill deep hole processing, with 10 um filter to filter. The filter equipment can avoid excessive pollution or excessive metal particles in the cutting fluid, which can help keep the cutting fluid clean and prolong the use cycle of cutting fluid. Modern automatic machine tools usually have cutting fluid filtration, separation and purification devices.
With overflow method, the cutting fluid can continuously flow to the cutting area and wash away the chip. The flow of the cutting fluid is larger to allow the cutter and workpiece to be submerged by the cutting fluid. In addition to providing appropriate cutting fluid to the cutting area, there should be sufficient cutting fluid to prevent abnormal temperature rise. In the deep hole drilling processing, cutting fluid, such as small, cutting fluid temperature rise quickly, when the oil temperature more than 60 ℃, cutting cannot proceed, so the deep hole drilling machine is generally equipped with large cooling tank.
3. High pressure method:
For some machining, such as deep hole drilling and hole drilling, use high pressure (pressure is 0.69-13.79 MPa) cutting fluid system oil supply. The deep hole drill is a single-blade bit, similar to the boring bore, except that there is a cutting fluid inside the drill. The drill hole drilling is a drilling method of drilling a cylindrical hole on the workpiece but leaving a solid cylinder. When the cutter enters the workpiece, the solid cylinder is drilled through the hollow cylinder head, and the cutting fluid is sent around the cutter with the pressure pump, forcing the chip to flow out from the center of the cutter. Set of drilling hole with cutting fluid must have good extreme pressure and sintering resistance, should be very low viscosity, can free flow around the tool, should also have good oil, in order to reduce the coefficient of friction between the tool and the workpiece, chip.
The cutting fluid can be sprayed into the cutter and the workpiece in the form of gas and oil mist. The cutting fluid is used by a small nozzle, which USES compressed air of 0.069-0.552 MPa to disperse the cutting fluid into small droplets into the cutting zone. In this case, the water-based cutting fluid is better than the oil-based cutting fluid, because the oil mist pollution environment of the oil based cutting fluid is harmful to the health and is easy to integrate the larger oil droplets. Spray method is best suited for machining with high cutting speed and low cutting area (such as end milling). Select the cooling performance of the cutting fluid, the small droplets with the hot cutting tools, workpiece or chip contact, can quickly evaporate the tropical walk. Spray cooling is not required to use a splash board, oil pan and return tubing, only a small ball, and the workpiece is dry, even if a bit of oil is dry.
5. Cooling liquid method:
Cooling liquid method is a lot of more phyletic, such as nitrogen, argon, carbon dioxide gas can be compressed into a liquid in the cylinder, the fluorine the available machinery compress a gas into a liquid, released when using, through regulating valve, by direct injection nozzle in the cutting zone, cooling by vaporization heat cutting tool, workpiece and cutting. This method has excellent cooling effect and is suitable for machining of difficult machining materials such as stainless steel, heat-resistant steel and high strength alloy steel, which can improve the tool durability greatly.
6. The central feeding system of cutting fluid:
For large and medium-sized mechanical processing plants, where possible, should consider adopting circulation system for machine tool cutting fluid supply, but it must be all the machine tools is to use the same kind of cutting fluid. Several grinders can be used to deal with the grinding of a conveyor system. Concentrated treatment of the cutting and grinding of the cutting fluid can reduce manpower treatment and improve working conditions.
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