Application of the hottest microemulsion

2022-10-23
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Application of microemulsion

in the process of metal cutting, due to the deformation of the processed metal, the cutting force and cutting temperature are generated due to the continuous friction between the tool and chip, and between the tool and workpiece, which seriously affects the cutting efficiency, processing quality and tool service life. Therefore, how to reduce the cutting force and cutting temperature is an important problem in machining. Practice has proved that reasonable selection of cutting fluid can improve machining efficiency, reduce machined surface roughness and prolong tool life

according to the properties of cutting fluids, cutting fluids can be divided into two categories: pure oil and water-soluble. Water soluble cutting fluids can be divided into emulsions, semi synthetic fluids (microemulsions) and synthetic fluids according to their composition. Microemulsion is a new cutting fluid between emulsion and synthetic fluid. It is a new generation of water-based cutting fluid after emulsion cutting fluid and synthetic cutting fluid. It is a microemulsion and translucent liquid formed by the high dilution of microemulsion oil with water. Microemulsion overcomes the defects of emulsion easy to decay, poor cleaning performance, synthetic cutting fluid eroding the paint surface of machine tools, poor lubrication performance and so on, avoids the disadvantages of oil pollution, mildew and deterioration, integrates the advantages of emulsion and synthetic fluid, and has the ability of extreme pressure, lubrication, cooling, rust prevention and cleaning of oil and water. It is an ideal cooling medium for machining lubrication of the new generation

principle and application

(1) the relationship between the tool and the workpiece in the process of metal cutting is very complex. There are great differences in different cutting processes, but the characteristics in the lubrication process are basically similar. In the process of metal cutting, there are mainly three kinds of deformation zones: (as shown in the figure) in the first deformation zone, the metal layer to be cut has plastic deformation under the action of the tool, resulting in shear slip. In the second deformation area, when the chips are discharged along the rake face, they are further squeezed and rubbed by the rake face, making the metal near the rake face fibrotic. In the third deformation zone, the machined surface is squeezed, rubbed and rebounded by the blunt part of the cutting edge and the flank, resulting in fibrotic work hardening

from these three deformation zones, it is almost impossible for cutting fluid to enter the first deformation zone, and it is possible to enter the second and third deformation zones. The cutting fluid penetrates into the deformation area through the tiny gap between the chip and the rake face, as well as between the cutting edge and the workpiece surface, forming an adsorption film on the surface of the tool and the chip, the tool and the workpiece, which is in a boundary lubrication state. It reduces the front knife, and this volume can not measure the friction and deformation between the surface and the chip, and between the rear knife face and the machined surface, which plays the role of lubrication and cooling. Therefore, the selection of cutting fluid is extremely important. Its lubricity, cooling and cleaning are the basic properties required in machining

according to the different processing, the performance of the selected cutting fluid also has its emphasis. For example, when tapping the thread with a tap, it generally focuses on the lubrication performance of the cutting fluid; However, when machining blind hole threads, the cleanliness of cutting fluid and the difficulty of cleaning after machining are extremely important; In the process of grinding, it focuses on the cooling and cleaning performance of cutting fluid. Therefore, we must be careful when choosing cutting fluid, and consider comprehensively according to different processing methods, part materials, etc. The excellent performance of microemulsion in lubrication, cooling, cleaning and other aspects saves us a lot of time in selecting cutting fluid. The following is a brief introduction of our application of micro lotion in tapping and grinding

(2) application in tapping processing generally, a pure oily and paste cutting fluid is used in tapping, that is, the cutting fluid made of white thick paint + an appropriate amount of engine oil or kerosene, commonly known as "lead oil". Lead oil needs to be constantly applied to the tool (TAP) during tapping. Due to the form of lead oil, the cooling and cleaning capacity of lead oil is seriously insufficient. In practice, we know that using lead oil as cutting fluid, although the tapping quality can meet the design requirements, the production efficiency is low, the chip removal is difficult, and the lead oil is easy to adhere to the thread surface, so it is very difficult to clean, especially for the processing of thread blind holes on large parts

in order to solve this problem, water-soluble cutting fluid instead of lead oil is a method we consider. For this reason, we have experimented with a variety of synthetic cutting fluids produced by different manufacturers, but China's new material industry is not ideal if it is large or strong. Although synthetic cutting fluid has good cooling and cleaning functions, its lubrication performance is poor, which leads to the thread tapping quality can not meet the design requirements, and the tool life is also low. Lead oil or synthetic cutting fluid have their own advantages and disadvantages. It is difficult to unify the advantages of these two cutting fluids when tapping threads

later, we used microemulsion as cutting fluid for thread tapping test. After many tests and comparisons, we selected the appropriate cutting parameters, and negotiated with the microemulsion manufacturer. After adjusting the formula of the stock solution and the ratio concentration of the cutting fluid, the quality of the processed screw holes is significantly improved when the disassembly of the experimental machine becomes richer than that of the synthetic cutting fluid and there is no welding treatment, which fully meets the design quality requirements. See Table 1 and table 2 for the comparison of the experimental results of machining threaded holes with lead oil and microemulsion cutting fluid. Table 1

note: material ZG threaded hole MH depth 25mm (blind hole)

tap m12-h2 machine tool Z3040

Table 2

note: material ZG threaded hole m20x to avoid dust entering the interior 1 H depth 40mm (blind hole)

tap m20xl 5-h2 machine tool Z3040

from the statistical results of the above two tables, it can be seen that using microemulsion as the cutting fluid for tapping threads has significantly improved the processing efficiency and cleaning performance compared with using lead oil as the cutting fluid. When processing threaded holes in large quantities, especially blind hole threads, using microemulsion as the cutting fluid should be vigorously promoted and applied

(3) application of microemulsion in grinding. The cutting fluid used in grinding in our company has always been the emulsion formed after dilution of emulsified oil + water. From the thermodynamic point of view, this cutting fluid belongs to an unstable system, which is prone to decay and bacteria, has a short service life, and has high requirements for water. In case of hard water or excessive electrolyte content in water, the stability of the emulsion will be reduced, and even demulsification will affect its use. Microemulsion belongs to a stable system from the thermodynamic point of view, and it is not afraid of hard water. Diluted water can contain more electrolytes, which is not easy to produce bacteria and has a long service life. We have cooperated with microemulsion manufacturers to prepare microemulsion for grinding. Its lubrication, cooling, rust prevention and flushing performance meet the requirements, especially in machining centers, CNC lathes and other machine tools, the application of microemulsion has achieved good results

precautions

microemulsion is a cutting fluid between emulsion and synthetic fluid, which has its particularity. The following problems should be paid attention to when using:

(1) the water tank and pipeline should be cleaned before liquid preparation

(2) prepare according to the specified proportion

(3) microemulsions of different brands and manufacturers should not be mixed

(4) it cannot be mixed with emulsion

(5) when replenishing liquid, water and microemulsion oil should be prepared in proportion before replenishing. It is forbidden to add water without original liquid

(6) microemulsion shall not be used for lubricating and cooling equipment using the same system, but only for lubricating and cooling equipment separated

(7) it should be replaced regularly. Replace the microemulsion with a new one when it is detected that there is a foul smell, or the microemulsion is stratified and discolored

(8) microemulsion is weakly alkaline, and the skin is weakly acidic. The surfactant in it has degreasing effect on the skin, so long-term contact will make the skin rough and dry, so pay attention to strengthen labor protection

conclusion

at present, the development of water-soluble lubricating additives in China is slow, which restricts the improvement of the lubricating performance of synthetic fluids; In microemulsion oil, the use of water-soluble additives and oil-soluble additives improves its lubricity. Compared with common emulsions, its permeability and cleaning ability are greatly enhanced, and the price is moderate. Therefore, microemulsions will be used more and more widely

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