Technical Research Of Some Problems On The Mechanism And Process Of Micro-scale Milling

It is necessary means that micro-fabrication technology manufactures tiny or operating very small scale micro-machinery and micro-electromechanical systems. Micro-manufacturing technology based on micro-machine tool system has many advantages on a three dimensional processing capability, a wide range of applicable work-piece material-s, low cost, and the high processing efficiency. So it is widespread concerned by industry and academia of the domestic and foreign. Especially, it becomes a hot topic and focus trends on the complex function, bulk flexible manufacturing and high precision manufacturing of micro-mechanical parts because of its benefits in line with micro-milling technology.In the micro-scale milling process, the strength and stiffness are not allowed the larger micro-milling parameters due to the small size of the parts. At the same time, the final machining layer thickness must be less than the precision value to ensure accuracy requirements of the parts. The feed per tooth may be less than the grain size of materials due to a very small chip thickness. The micro-edges may destroy the grain boundary when it is cutting in the grains. The stress on the blade will be a sharp increasing with high spindle speed. The micro-milling edge will simultaneously scratch and squeeze materials combined with the minimum chip thickness effect. Its results have significant change on wear of micro-edge, micro-milling forces process and the quality of the work-pieces. Therefore, the traditional theory of milling principle and processing has been unable to effectively guide and explain the characteristics of micro-scale milling process performance.The key of solving problem the above is to establish the methods and models of micro-scale milling process and a large number test of micro-milling. In this paper, a combination means of theoretical guidance and practical test are used based on micro-milling system test platform Meanwhile, the different micro-milling parameters and different materials as research supporters, the dynamic stability of the micro-milling, micro-milling force, the quality of the parts, the distribution of temperature field, wear of micro-edge and so on are researched in micro-milling processing. And several other research work also. The main contents are as follows:(1) To explore dynamic variation of micromachining of the micro-milling edge. The average tooth angle method and the theory of Fourier frequency method based on the RC method are applied. The micro-milling dynamic lobes are acquired with the help of digital simulation means according to the actual processing parameters. The micro-milling parameters corresponding to the different processing materials and different spindle speeds and axial depths of cut are initially identified The micro-milling tests are carried out according to the acquired theory processing parameters in order to research chatter of micro-milling. This approach also provides a theoretical basis for the followed test processing.(2) The forces of micro-milling can be indirectly speculated that wear of micro edges, the quality of the parts, the material impact on the micro-milling and so on. The model of micro-milling force is established combined with the actual processing conditions in theory. So the law of dynamic and static force is obtained The different characteristics of the material and different number of teeth micro-cutter are applied at the same processing conditions in the test. The forces of dynamic and static micro-milling are accurately measured by dynamometer. To The characteristics of micro-milling process performance are inferred in order to better understand the mechanism of micro-milling. Consequently, the theory of micro-milling is in-depth researched by test accumulation.(3) Parameters of micro-milling, material properties and micro cutter have an impact on quality of parts and so on. Micro-grooves are selected as the objects of processing. The laws are obtained by the research on quality of the bottom surface and distribution of edge burr of micro-grooves. From a theoretical point of view, the effect on the quality of the micro grooves are analyzed and researched at different micro-milling parameters, different materials and different micro-cutters conditions. The factors on affecting the quality of the micro-parts are determined and it provides a theoretical basis for improving manufacturing precision of the miniature parts.(4) The distribution of temperature field corresponding to wear of the micro-edge can be not researched on the test conditions now Thus, wear of micro-edge is researched by the digital simulation. The edge radius gradually increases due to micro-cutter edge wear. The distributions of internal temperature are obtained in materials, chips and micro-cutters by test on different micro-edge radius. The tendency of temperature corresponding to different of parameters and materials under the same conditions are obtained by infrared measurement test. Finally, the results both numerical simulation and experimental temperature measurement are analyzed in order to understanding in-depth distribution of temperature field.(5) The amount of micro-cutter wear can not be accurately measured and evaluated by using conventional methods.Therefore, a new method is proposed due to some inevitable link to both the groove width and diameter of micro-cutter. The amounts of micro-cutter wear are obtained indirectly by measuring accurately dimensions of micro-groove. Finally, the law of micro-edge wear is summarized through the different micro-milling parameters corresponding to the different micro grooves.(6) The basic parameters of stable machining are obtained by research on mechanism and process of micro-milling mentioned above. The typical parts are manufectured in order to verify the correctness of the foregoing parameters in reducing wear of the micro-edge and improving the life of the micro-cutters of view. The analysis above is to prove the accuracy of the machining process.Finally, The main conclusions of the paper are summarized and elaborated and some of the proposals work are put forward on about the next phase of the research based on the theoretical and experimental problems are found in test.