Research On Tool Wear Characteristics And Control In Precision Cutting Pure Iron Curved Components

Pure iron materials are widely used in aerospace,energy and power,national defense and military industries due to their excellent plasticity,impact resistance and electromagnetic properties.However,pure iron is a typical difficult-to-machining material.During cutting pure iron,the cutting deformation is large,the work hardening is serious,and the tool wear is fast.Tool wear has a serious impact on cutting force,surface quality,residual stress,processing accuracy,etc,and is an important factor affecting high-precision pure iron thin-walled components.Therefore,it is important to improve the manufacturing accuracy of pure iron thin-walled curved surface components by probing tool wear characteristics during precision cutting of pure iron curved surface components and their influence on the contour accuracy.The main research work of this article includes:(1)Pure iron end face cutting tests was used to study tool wear modes and mechanisms in the precision cutting process.The test results show that main tool wear modes are flank wear,major notch wear,minor notch wear and tool nose wear.Major and minor notch wear are greater than the average flank wear.Tool wear mechanisms are the results of the combined effects of adhesive wear,oxidative wear,and diffusion wear.(2)It was studied that the effect of pure iron material grain size and cooling lubrication on tool durability during end face cutting,and influence mechanisms of MQL and plasma on tool wear.The results show that pure iron grain size and cooling-lubrication methods will not change the tool wear modes,but will affect major notch wear,minor notch wear and flank wear.MQL can effectively reduce tool wear and suppress the occurrence of major notch wear.Plasma can also improve tool durability at high speeds.Pure iron material has super lipophilic properties,and it is easy to form a lubricating film between tool and workpiece under MQL.The plasma can modify pure iron surface.Pure iron surface changes from hydrophilic to superhydrophilic after plasma treatment,and the surface hardness decreases.(3)Tool wear characteristics of the precision cutting pure iron curved components were studied.Based on the theoretical position of major notch wear and minor notch wear in end face turning,a mathematical model of notch movement along the tool nose was established.By comparing and analyzing the difference in tool wear between pure iron curved cutting and pure iron end cutting,It is found that notch wear disappears during curved surface cutting,only the flank wear land exists,and flank wear band width is about twice that of the end face cutting,which indicates that major notch wear and minor notch wear participates in theformation of the flank wear land,and confirms the rationality of major and minor notch wear movement model.(4)The influence of tool wear on the contour accuracy of pure iron curved components was studied.Based on tool degradation characteristics and the tool reflection,a mathematical model is established about the effect of tool wear on the contour accuracy.By comparing and analyzing tool wear of curved surface cutting under dry cutting,MQL and plasma.MQL can effectively suppress flank wear and tool nose degradation of the cutting edge during the cutting process of pure iron curved components.This will lay the foundation for improving the contour accuracy of pure iron curved components.