Grinding is one of the most common machining methods in metal cutting. The grinding surface is of high precision, and the dimension tolerance grade can reach IT5 ~ IT6, with high surface finish. Another feature of grinding is not only can be a variety of carbon steel, cast iron, non-ferrous metals, but also to grind high hardness of hardened steel, all kinds of cutting tools and cemented carbide [1]. In the grinding process, the grinding wheel and the workpiece material can occur between grinding and scratching and scratching, resulting in a large number of grinding heat, planing, milling and cutting in different ways, planing, milling cutter cutting mode is about 70% ~ 80% of the heat accumulation in the chip flows away, coming into the workpiece material about 10% ~ 20%, the incoming tool is less than 5%, but due to grinding of metal material is grinding thin, about 60% to 90% calories was introduced into the workpiece, only less than 10% of the heat is grinding away, resulting in a large number of grinding heat on the surface of the workpiece, the grinding zone temperature can reach 400 to 1000 DEG C about 2, in such a high temperature, material deformation and the grinding wheel will burn, serious wear, grinding quality. In order to reduce the grinding temperature, reduce the abrasion of the grinding wheel, prolong the life of the grinding wheel, and improve the surface quality, it is necessary to choose the appropriate grinding fluid.

Most grinding processing precision and roughness of the workpiece is relatively high, so the use of grinding fluid, so it requires the following functions:

(1) cooling function grinding fluid should have better cooling function than other working fluids. It can take a lot of heat in the grinding area, reduce the grinding temperature, improve the durability of the grinding wheel and improve the production efficiency.

(2) in the grinding process, the grinding wheel must bear the working pressure. The grinding fluid can penetrate into the tiny gap between the grinding wheel and the surface of the workpiece to form a thin film, which can reduce the friction factor, prolong the life of the grinding wheel and improve the surface finish of the workpiece.

(3) the debris produced in the grinding process and the falling sand on the grinding wheel can be attached to the workpiece and the grinding wheel if it can not be washed away quickly. Impact on workpiece precision and surface finish. So it is necessary to have good cleaning performance.

(4) if the grinding fluid can not provide good antirust function, it may cause the workpiece to rust, so that the product can be scrapped. Therefore, the grinding fluid with certain antirust property should be selected.

Through the use of several kinds of grinding fluid and dry grinding compared to the lubrication effect, the use of grinding fluid processing lubrication effect, in the high-speed operation of the process, the grinding wheel surface and the workpiece surface friction. Grinding pressure is very high, the maximum temperature of 1000 degrees celsius. At this time, if the use of grinding fluid can not play a good lubrication function, it will cause serious wear wheel, reducing the processing accuracy and surface finish. In addition, whether the grinding fluid can penetrate into the grinding zone directly affects the cooling and lubricating effect. Whether it is inside and outside grinding grinding, or grinding, if the nozzle position of grinding fluid on grinding fluid pouring faults resulted in the wrong direction, then the grinding fluid due to high-speed rotating wheel greatly hindered the air can not enter the grinding zone, so that the machining process in grinding can not be cooled, then grinding the grinding heat liquid on the grinding zone has no cooling effect on the whole of the work can only reduce the temperature effect. There exists grinding fluid grinding costs, environmental issues and influence health problems of several processors.

In the grinding process, the use of appropriate grinding fluid, to improve the surface finish, the effect is often greater than the thickness of grinding. In order to effectively ensure the best function of grinding fluid, so that the four functions of the real implementation, to play its role, I think we must strengthen the following work:

(1) to ensure that the grinding fluid is not corrupt and deteriorated

1) the reasons for the deterioration and deterioration of grinding fluid

The spoilage of grinding fluid is a result of the rapid propagation of microorganisms under certain conditions, which results in the biochemical changes of grinding fluid. Microorganisms that cause spoilage include fungi, bacteria and yeasts. These fungi can be found in the atmosphere, soil, rivers, natural objects and so on. There are several kinds of representative bacteria in the degradation of grinding fluid:

A, copper green gram bacillus: one of the main bacteria of grinding fluid spoilage.

B, sulfate reducing bacteria: another major bacteria in the grinding fluid odor, under anaerobic conditions, there are rust. Scale, it can reduce the sulfate, hydrogen sulfide, the smell; hydrogen sulfide corrosion of iron.

C, yeast: bacteria will produce strong enzymes, so that grinding fluid sticky, corrupt.

2) conditions for rapid propagation of microorganisms

A, nutrient source fully: grinding fluid for the reproduction of microorganisms to provide a full range of organic matter (carbohydrates, fatty acids, fatty alcohols......) Minerals and trace elements, nitrogen compounds (organic nitrates, etc.), as well as sulfur, phosphorus, etc..

B, oxygen: aerobic bacteria will produce light odor, anaerobic bacteria will produce odor, facultative anaerobic bacteria will produce light odor.

C, temperature: bacteria in 30 ~ 37 degrees easy to breed, mold in 20 ~ 30 degrees of easy reproduction.

D, pH value: bacteria in pH7.0 ~ 8.5 easy to breed, mold in pH4.5 ~ 7 easy to breed, pH>9 bacteria, fungi breeding probability is the smallest.

3) grinding fluid corruption