Theoretical Analysis Of Atomization Mechanism And Experimental Study Of Oils On Water (OoW) Cutting Fluid

In process of machining, cutting fluid is usually used to reduce cutting force, lower cutting temperature, extend tool life and enhance machining efficiency and surface finish quality. However, conventional cutting fluids not only have bad effect on environment and health but also increase production costs. The current attention on the environmental impacts of machining processes by governmental regulations has been forcing manufacturers to reduce or eliminate the amount of wastes. Therefore, more and more new green cutting methods are being the focus of attention in manufacture field in the 21th century. Because Oils on water (OoW) cutting fluid is cheap, pollution-free, eco-friendly and no recovery, OoW cutting fluid used as coolants and lubricants is a new green cutting technique. It utilizes the strong action of compressed air, naturally decomposable plant oil and a small amount of water to create a tiny amount of Oils on water (OoW) cutting fluid in the special multipart nozzles. Therefore, we have made a study on action mechanism and experiments with OoW as coolant and lubricant in green cutting, which is of great theoretical significance and practical value.(1) This thesis about Oils on water (OoW) cutting fluid makes a deep study of mechanism theory.1) This thesis makes a study of the forming mechanism of plant oil and eater oil changed into Oils on water (OoW) cutting fluid, determining to use high dynamic viscosity canola oil as the applied oil.2) This thesis makes performance analysis of atomization nozzles and jet theory study.3) This thesis makes an analysis on the stability of column viscous liquid jets in swirling gas in the case of 3-D considered. The characteristic equation is obtained which delineates the evolution of a general 3-dimensional disturbance on the free surface of an incompressible viscous liquid jet, then by combining the complex analysis with implicit function existence theorem, the existence and uniqueness of the solution of the characteristic equation has been proven. Both the evolution of disturbances on the free surface of a liquid jet and its relative intensity are applied to analyze the mechanics reason of and difference between the breakup and atomization. Here, a new dimensionless parameter Te= We/Qis introduced as a criterion to distinguish between the breakup mode and atomization mode. The parameter indicates disturbance modes on free surface of a viscous liquid jet characteristic. That is to say that, within the range of Te> 1, axisymmetric disturbance on free surface of liquid jet is at a absolute advantage, which is the most instable disturbance modes; within the range of Te< 1, non-axisymmetrical disturbance on free surface of liquid jet arises. In the meantime, along with the reduction of Te, increment rate becomes more increasing.It finally becomes the most instable disturbance modes. Within the range of Te＜＜1, defferent angular modulus multi-format non-axisymmetrical disturbance on free surface of liquid jet simultaneously arises, their intension grade being at the same level. Then a unified theory about the breakup and atomization of viscous liquid jets has been raised based on the linear theory.(2) Homogeneous transform has been applied to the structure design of the nozzle, and the formation of line of intersection equation is made simple and easy. Formulas have been presented about the section area of exit flow determined by the structure parameters of nozzle, about the relationship between flow rate characteristic and structure parameters of nozzle, and about characteristic sizes of orifice. On this basis, Oils on water (OoW) cutting fluid multi-function supply equipment and special multipart nozzle have been improved.(3) Improved Oils on water (OoW) cutting fluid multi-function supply equipment and special multipart nozzle are used to experiment in the lathe, grinding machines and machine Centers,and with satisfactory experimental results.1)The turning experimental results showed:with OoW as coolants and lubricants, the main cutting force,the path force and the feed force are lower than the cutting force by dry cutting method and oil water emulsion cutting method. And the effect on reducing cutting force is more obvious when OoW cutting fluid is sprayed at flank face. This cutting fluid can effectively take away the heat and reduce cutting temperature. So it can improve the tool life. In the experiment studied of tool life, the tool life, using Oils on Water (OoW) cutting fluid spray direction at flank face, is 1.57 times,1.46 times compared to the tool life using dry cutting method and oil water emulsion cutting method when cutting 45 carbon steel process; and is 1.54 times,1.14 times compared to the tool life using dry cutting method and oil water emulsion cutting method when cutting 1Cr18Ni9Ti stainless steel process. On the experiments studied of surface finish, Oils on Water (OoW) cutting fluid can also effectively reduce surface roughness compared to dry cutting method and oil water emulsion method, therefore, surface quality is greatly improved.2)The experimental results in the grinding machines and machine Centers showed: compared to emulsion, horizontal milling force approximately rduces 30%; while the roughness value of processed surface is approximately the same. While measuring milling force,with milling depth 1μm, milling quantity 30μm and milling width 30mm as conditions,OoW cutting fluid milling force is the smallest, by approximately 30%. OoW cutting fluid makes the smaller surface roughness of the milling part.From theoretical analysis of mechanism and experimental results,Oil film of OoW cutting fluid has fine lubrication effect. At the same time, Water drops of OoW cutting fluid absorbs a great deal of heat in metal cutting process,reduces surface temperature of cutting processing zone, reduces tool wear and extends tool life, restrains built-up edge (BUE) and scale and reduces surface roughness of parts. Therefore,OoW cutting fluid is a great challenge to conventional cutting fluid, and it will be popularized and disseminated, and its wide application in the manufacturing will definitely bring about an all-round transformation of traditional processing method in the manufacturing enterprise and update machine tool, create great pushing effect on beautifying the environment, the development of science and technology, economic construction and social development.Accordingly the reseach of OoW cutting fluid has not only immediate economic benefit, social benefit and environmental benefit but also a bright future in application.