Rational use of cooling methods
In grinding, a strong airflow layer is generated on the surface of the grinding wheel rotating at a high speed, so that the cooling fluid is difficult to enter the grinding zone, and a large amount of cooling fluid is poured on the machining surface which has left the grinding zone. At this time, burns have already occurred. Therefore, it is necessary to use cooling methods reasonably.
Adopt high pressure and large flow cooling.
1. This can not only strengthen the cooling effect but also can wash the grinding wheel surface so that its gap is not easy to be blocked by cutting. To prevent spatter of coolant, the machine tool shall be equipped with a protective cover.
2. Install coolant nozzle with air baffle on the grinding wheel.
In order to reduce the high-pressure adhesion airflow on the surface of the high-speed rotating grinding wheel, a coolant nozzle with an air baffle can be installed as shown in Figure 3, so that the coolant can be injected into the grinding zone smoothly.
3. Achieve internal cooling.
Since all the pores of the grinding wheel can reach water, the coolant can be fed into the grinding zone through the wheel under the action of centrifugal force. In order to prevent the gap of the grinding wheel from being blocked by the coolant, special attention should be paid to the cleanliness of the coolant during internal cooling grinding.
4. Right Angle nozzle.
Right-angle nozzles have been widely used in high-speed grinding because of their simple design and outstanding effect. The right-angle nozzles basically eliminate the blocking effect of airflow on grinding fluid in a wide range of wheel speed V =(40 ~ 150)m/s.
5. Impregnated grinding wheel.
The liquid-solid lubricant penetrates into the pores of the grinding wheel and covers the grinding particle surface. During grinding, the abrasive particles and chips are formed, and the lubricating effect of the abrasive particles and the machining surface is formed.
6. Self-accelerating method.
By using the principle of liquid dynamic pressure, the grinding fluid can get a speed equal to the wheel cycle speed, thus producing a synchronous cooling effect.
7. Low temperature compressed air cooling.
The compressed air is cooled to (-110 ° C) by liquid nitrogen (-192 ° C) in the heat exchanger and then cooled by the nozzle to the grinding zone. To prevent water in the air from freezing in the heat exchanger pipe when the temperature drops, an air dryer must be used. This is a new technology instead of the traditional grinding liquid cooling method.
Grinding burns in the production process often appear, in addition to the above measures, but also to pay attention to heat treatment and strictly abide by the process discipline.