Study On The Formation Echanism And Characterization Method Of Micro Cutting Burr

With the rapid development of mechanical manufacturing science and technology,the requirements of machining quality for miniaturized,accurate and lightweight mechanical parts are becoming higher and higher.Micro cutting technology has the comprehensive advantages of wide range of materials,stable quality,high production efficiency and low processing cost,which has become one of the main research contents of advanced machining processing and manufacturing technology,and it is highly concerned by mechanical engineering experts and scholars all the world.Because the micro cutting burr is mainly formed in the process of machining,its size and shape directly affect the machining quality.Therefore,the research has a very high theoretical research value and a wide prospect of engineering application on the formation mechanism of micro cutting burr and the technology of suppression and removal.On the basis of metal cutting experiments,this paper systematically studies the formation mechanism,prediction and characterization method of burr in micro turning,drilling and milling.In this paper,the cutting theoretical model of burr formation is established,the basic law of burr formation and its change is revealed,and the prediction of burr formation and change law is basically realized,the characterization method of edge(burr)quality based on surface quality is proposed,and the technology,process and method of active control of metal cutting burr is proposed in combination with the machining experiment.The main research work and achievements of this paper are as follows:First of all,this paper based on the theory of system engineering,the main factors that affect and restrict the formation of burr are given.The experiments on the formation of micro turning,milling and drilling burr are carried out systematically,the changes are observed and studied,and the basic laws of the formation and the change of cutting burr are revealed systematically.Secondly,based on Johnson cook(J-C)strength theory,the formation model of micro cutting burr is established.It describes the dynamic behavior of Al2024-t6 from low strain rate to high strain rate,and gives the constitutive relation under the condition of high stress,high strain and high temperature field.Using Arbitrary Lagrangian Eulerian(ALE)technology,the simulation of burr formation is carried out,and the prediction of burr formation in micro milling is preliminarily realized.Thirdly,based on the data analysis of the micro metal cutting test results,the burr forming process and its changing law are revealed.The micro end milling cutter of cemented carbide is selected to cut forged aluminum 6061 and aluminum alloy AlSi9Cu3,so as to study the influence on the formation and change of burr by cutting parameters,geometric parameters of cutting tools,shape of cutting surface,etc.It finds five stages of burr and defect formation and their transformation conditions.These further enrich and improve the theory of metal cutting burr formation.Fourth,it proposes a comprehensive evaluation system of machined surface based on Metrology and simulation experiment.According to the modern cutting surface quality theory-surface integrity,the quality of machined surface(including edge)is divided into surface quality,edge(burr)quality and surface quality.This paper puts forward the "cutting quality evaluation method(draft of national standard)" and "cutting burr detection method(draft of national standard)",which lays a foundation for the normalization,standardization and scientific construction of burr research.Fifthly,based on asp.net platform,the paper builds a network expert knowledge system of burr,develops a burr knowledge expert system composed of micro burr quality knowledge base,database and rule base,and builds a docking platform of burr theory research and engineering application.Sixth,based on the optimization of tool parameters and cutting path,the active burr control technology is developed,which lays the foundation for the realization of less burr free machining.According to the experiment and analysis of micro cutting,the accuracy principle,efficiency principle and position principle of active control of micro cutting burr are expounded.Combined with the specific machining experiment,the technology,process and method of active control of burr are put forward,such as improving part structure design,adjusting tool parameters,optimizing machining process and cutting path.As a part of the NSFC(No.51075192)and the national major science and technology special project "surface integrity testing technology and evaluation method for CNC tool cutting"(No.2013zx04009031-5),the research work and results can further enrich and improve the metal cutting theory,promote the development of ultra precision machining and micro cutting technology in China.Its application will bring good economic and social benefits.