| With the rapid development in economy around the world, High-accuracy miniaturized components are increasingly in demand for various industries, such as aerospace,biomedical,electronics,environmental,communications,automotive and so on. This miniaturization will provide Microsystems that promise to enhance health care, quality of life and economic growth in such applications as microchannels for lab-on-chips, shape memory alloy'stents', fluidic graphite channels for fuel cell applications, subminiature actuators,sensors and medical devices.Thus, The miniaturization of machine components is perceived by many investigators as a requirement for the future technological development of a broad spectrum of products. Miniature components can provide lower power consumption and higher heat transfer, since their surface-to-volume ratio is very high. To create these components,micro-meso-scale fabrication using miniaturized mechanical material removal processes has a unique advantage in creating 3D components using a variety of engineering materials. The motivation for micro-mechanical milling stems from the translation of the knowledge obtained from the macro-machining domain to the micro-domain. However, there are challenges and limitations to micro-machining, and simple scaling cannot be used to model the phenomena of micro-machining operations.Thus,it is necessary for us to investigate the principles of micro-milling.The investigations in micro-milling include these fields,such as minimum chip thickness,chip formation,milling force,milling temperature,micro-milling machinability,tool deflection,surface roughness,milling instability,burring,built-up edge,tool wear and finite element analysis or molecular dynamics simulation and so on. Many a investigators in the world have been stuying in this field,and getting significant achievement,but they haven't built up the theoretical framework of the field. The author investigates the steel material of 40 Cr,vividly describes the process of chip formation,residual stress in the machined surface and the temperature distribution in the workpiece by FEA。The FEA output could provide the simulation proofs to the coming design and investigation of the experiment scheme.finally,the author explains the principles about the minimum chip thickness effect, surface quality,micro-milling forces and so on,the above investigation will make people further understand the manufacturing principles.Firstly,the current demestic and abroad development situations are discussed,then the situation of techniques and mechanics in micro-milling is summarized,the author refers to the the methods of investigation according to the true condition in the laboratory,and its research signification,methods,main contents and overall structure are listed.In chapter 2,based on the metal micro-milling principles and FEA situation status,the 2D thermo-mechanical finite element model is constructured.In addition,the chapter particularly describes the process of the FEA modeling and the detail settings about the software. Afterwards,the process of orthogonal cutting is successfully simulated according to the dynamics and constitutive parameters.In chapter 3, The microstructure of mild alloy steel——40 Cr is got by metallographical experiment, the author fully investigates the design of the experiment scheme according to the output of the FEA and the next research contents,then the future phenomenons that may occur in the coming experiment is predicted in advance.At last,the author gets the related experiment datas which will be used to conclude the principles in micro-milling.Based an the experiment datas above, the minimum chip thickness effect,surface quality and micro-milling forces are particularly analyzed in chapter 4,and the correlative principles of micro-milling are investigated from the point of theoretical analysis to interpret the related phenomenons.Finally,systematical summary is given,and the future work is put forward according to the research results in the thesis in chapter 5.
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