Research On The Influence Of Tool Wear Effect On Hard Turning Process

Hard turning is a process method widely used in the contemporary manufacturing industry.As the final forming process of some difficult-to-machine materials,it has alleviated the grinding processing method currently commonly used.Because of its clean and environmentally friendly processing methods,hard turning has gradually replaced the grinding process.With the emergence of many emerging high hardness materials,the biggest challenge facing hard turning is the wear resistance of the tool.Tool wear is largely related to machining surface roughness,machining efficiency,and tool life.In this paper,the hard turning process of structural steel AISI 4340 is taken as the research object.The reverse thinking simulation modeling explores the impact of worn tools on hard turning,so as to better grasp the mechanism of tool wear.This article has completed the following based on finite element simulation software:First,the wear mechanism and form of the tool are analyzed,and the physical model of the tool after wear is established according to the type of tool wear,and the force and cutting heat of the tool after the wear are analyzed.During hard turning,crater-shaped flank wear,smooth wear-band shaped flank wear,and blunt form of boundary wear and front and back tool wear are often formed on the tool.In this regard,we have established four geometric models of worn tools,each of which uses three types of wear parameters to model in the blunt range.Since the effective structure of the tool will also change after wear,the force and heat transfer of the wear model are analyzed.Secondly,using reverse thinking simulation modeling,based on Advant Edge finite element simulation technology,based on the tool wear geometric model,four wear tool simulation models were established,the meshing and material property definition were performed,and Johnson-Cook material model was used to contact The friction and wear model and chip separation criterion are used to simulate the cutting process.The comparative analysis of different forms of worn tools and non-worn tools was performedby extracting the simulated clouds and curves in the post-processing interface,and the effects of tool wear on cutting force,cutting temperature,chip formation,DMZ and Mises stress were discussed.Then,we analyze the mechanism of a tool with a smoothing edge that is commonly used in hard turning.In terms of structure,the smoothing edge tool is a transition form of the main cutting edge and the secondary cutting edge.It is an extreme form of the secondary cutting edge.The purpose is to increase the impact resistance and wear resistance of the cutting edge and reduce the surface roughness.According to the cutting edge structure of the smoothing tool,two types of smoothing tool models were established for simulation analysis,and compared with conventional tools.Finally,a series of conclusions are made on the impact of tool wear effects,and the impact of different forms and degrees of tool wear on the hard turning process is discussed.The conclusions drawn from this study indicate that tool wear has a significant impact on cutting force,cutting temperature,and chip formation.And among several kinds of tool wear,the crescent-shaped rake face wear has the most obvious effect on the cutting process.Crescent wear not only changes the effective rake angle of the tool,but also acts as a chip breaker during the cutting process.