The Development Status And Future Trends Of Cutting Fluid Technology
時間：2020/10/13 關鍵詞：YongPu Precision 瀏覽量：17436
In the development process of cutting fluid technology, we can see two characteristics: First, the number of cutting fluid products is increasing, the types are becoming more complete, and the functions are becoming more refined. Corresponding cutting fluids are available for different machining methods. Second, the technology of cutting fluid is becoming more and more perfect, so the machining efficiency is continuously improved.
In addition, with the rapid development of modern manufacturing industry and people's increasing emphasis on environmental protection, cutting fluid technology is also in a cycle of improvement and renewal, and new cutting processing technologies are constantly emerging.
The current state of development of cutting fluid technology
Faced with the increasingly mature development of the cutting fluid market and the diversification of cutting fluid products, the International Organization for Standardization and some industrial developed countries have formulated relevant cutting fluid classification standards. The American Society for Testing and Materials has formulated the classification standard ASTM D2881—03 for metalworking fluids and related materials, and the Japanese Standards Association also formulated a new cutting fluid standard JIS K2241 in 2000.
Our country formulated the national standard GB/T7631.5—1989 "Classification of Lubricants and Related Products (L class) Part 5: M group (Metalworking)" in 1989, which divides metalworking lubricants into two categories, namely, the processing types that emphasize lubricity and the processing types that emphasize cooling. It is worth mentioning that, like the standard formulated by the American Society for Testing and Materials, our country's classification standards also include lubricants used in metal forming processing, such as forging, sheet bending, drawing, rolling, rather than the lubricants discussed in this article for removal processing (i.e. cutting processing) types, so it will not be repeated here.
Although various classification standards are different, they are generally divided into two major categories, water-based and oil-based, according to the composition and state of cutting fluid.
Water-based cutting fluid needs to be diluted with water before use, and can be divided into emulsified cutting fluid, micro-emulsified cutting fluid, and synthetic cutting fluid according to the state after dilution. The original liquid of emulsified cutting fluid generally does not contain water, and the cutting fluid after mixing with water is in an emulsified state; synthetic cutting fluid original liquid generally does not contain oil, so it can be mixed with water, and the cutting fluid after mixing is mostly transparent; micro-emulsified cutting fluid The original liquid contains a small amount of oil (i.e. the content of oil additives is small), and the content of surfactants and anti-wear agents is large, and the cutting fluid after mixing with water is semi-transparent and micro-emulsified, and the appearance is between the above two.
Oil-based cutting fluid (also known as cutting oil) is generally used directly, with the basic component being the base oil. According to different processing needs, various additives with different properties are added, resulting in different types of cutting oil. Oil-based cutting fluid can be roughly divided into pure mineral oil, pure synthetic oil, active extreme pressure cutting oil, non-active extreme pressure cutting oil, and anti-friction cutting oil according to the difference of base oil and additives.
Cutting fluid process technology
As mentioned above, cutting fluid is generally based on base oil or oil-soluble additives, and is formed by adding a variety of additives with different properties and functions to the base oil or oil-soluble additives and mixing them. Therefore, additives are the core elements in the process technology of metal cutting fluid, and excellent additive formulation has become a necessary condition for enterprises to improve their own brand market competitiveness.
The main role of metal cutting fluid in mechanical removal processing is cooling, lubricating, cleaning, and preventing. Since the convection and vaporization of the liquid can reduce the temperature of the tool and the workpiece surface, it prevents the burning and deformation of the workpiece surface.
At the same time, the cutting fluid cleans and takes away the chips generated during cutting, avoiding secondary cutting caused by the chips mixed between the workpiece and the tool, which affects the surface quality of the workpiece. Except for water-soluble synthetic cutting fluid, the oil compounds (from the base oil or oil-soluble additives) in other cutting fluids adhere to the surface of the workpiece and form an oil film through their polar groups, which reduces friction during cutting.
In cutting fluid containing extreme pressure additives, compounds composed of elements such as halogen, sulfur, and phosphorus react with the metal on the surface of the workpiece at high temperature and high pressure for a moment, forming a substance layer with low shear strength, which not only reduces friction but also prevents the adhesion of metal surfaces.
In addition, antioxidants (to prevent cutting oil from oxidizing at high temperature and high pressure), anti-vaporization agents (to prevent cutting fluid from volatilizing and producing misty liquid), and defoaming agents (to prevent cutting fluid from foaming and causing dry grinding phenomenon when sprayed) need to be added to the cutting fluid.
In water-based cutting fluid, there are also some special additives, such as corrosion inhibitors (to prevent metal corrosion), surfactants (to reduce the surface tension of the oil layer and change the interfacial state of the system), anti-mildew and bactericides (to prevent the growth of microorganisms and cause cutting fluid to deteriorate), and stabilizers (to protect the emulsified state), etc.
It is worth noting that when these additives are mixed with the cutting fluid to form the finished product, it is not only necessary to ensure that there is no chemical reaction between these substances, but also to ensure that the cutting fluid maintains a consistent performance during the processing of the workpiece and does not undergo unnecessary, irreversible chemical changes with the metal being processed.
Application of Cutting Fluid in Metal Machining
As mentioned earlier, different cutting fluids are used for different cutting methods. Therefore, in the actual operation of cutting fluid, it is necessary to choose the appropriate cutting fluid according to your own situation.
Firstly, the choice between water-based cutting fluid and oil-based cutting fluid needs to be considered. Generally speaking, oil-based cutting oil is more expensive and has more comprehensive performance. For more expensive machine tools or if it is required that the workpiece obtain a better surface quality and maximize the life of the tool, it is recommended to use cutting oil; if the processing efficiency and cost are the main reference factors, then water-based cutting fluid can be selected.
Secondly, it is necessary to refer to the characteristics of the machine tool itself. Usually, machine tool manufacturers often recommend some brands of cutting fluid for their own equipment, because they have considered the use of cutting fluid when designing the machine tool. For example, some open machine tools cannot use oil-based cutting fluid, otherwise, a large amount of cutting oil will volatilize and dissipate.
Thirdly, since the materials of the tool and the workpiece are different, their heat resistance, cutting index, hardness, etc. are also different, and different cutting fluids need to be selected accordingly. For example, diamond tools have a very high hardness, and in order to achieve a good cooling effect, water-based cutting fluid is generally used; for the processing of workpieces with low hardness, such as gears, it is necessary to use cutting fluid with high viscosity to prevent surface scratches.
Fourthly, the specific cutting method of metal cutting will also require the corresponding cutting fluid to cooperate. In modern mechanical processing, there are many kinds of cutting methods, such as turning, milling, drilling, threading, grinding, etc. As for fine processing and heavy cutting, the operation method undoubtedly puts forward higher requirements for cutting fluid.
