The cutting speed of grinding is high, so the power consumed during cutting is large, and most of its energy is converted into heat energy. This heat does not pass deep into the workpiece but concentrates on the surface of the workpiece. So there is a large temperature difference between the surface and the inside of the workpiece. When the surface temperature is very high (the temperature of the grinding point can reach more than 1500℃ in an instant, and the average temperature of the working contact area is 500~800℃), the processed surface will appear burns and thermal deformation, affecting the quality and finish of the processed surface. So in the whole grinding system, the correct selection of grinding fluid is also an important method to improve the surface quality of the workpiece and prolong the service life of the grinding tool.
Grinding fluid can be divided into oil-based grinding fluid and water-based grinding fluid according to the chemical composition of the oil.
1. The water-based grinding fluid is divided into emulsion grinding fluid, microemulsion emulsion grinding fluid (also known as semi-synthetic grinding fluid), and synthetic grinding fluid.
Emulsified grinding fluid. It is mainly composed of emulsified oil and water.The concentrate consists of mineral oil 50 ~ 80%, fatty acid 0 ~ 30%, emulsifier 15 ~ 25%, antirust agent 0 ~ 5% and preservative.
2. Forming grinding fluid. Do not contain mineral oil, concentrated by a variety of water-soluble functional additives. Extreme pressure agent, the oily agent, anti-rust agent, surface active agent, and defoaming agent, etc, diluent heat faster, clean sex strong, transparency, good, have good visibility of workpiece. And half a synthetic grinding liquid ratio, its stability and ability to resist corruption is strong, but relatively poor lubrication performance.
Semi-synthetic grinding fluid.The concentrate consists of mineral oil 5 ~ 30%, fatty acid 5 ~ 30%, extreme pressure agent 0 ~ 20%, surfactant 0 ~ 5% and rust inhibitor 0 ~ 10%.Semi-synthetic grinding fluid is transparent or translucent, which not only has good lubrication and cooling performance of emulsified grinding fluid but also has the advantages of excellent cooling, cleaning, and transparency of synthetic grinding fluid.