微细群孔电火花加工间隙流场分析及电极损耗研究

发布时间：2018-03-11 16:11

本文选题：微细群孔电火花加工　切入点：间隙流场　出处：《哈尔滨工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着科学研究及工业技术的飞速发展,微细群孔结构零部件得到广泛的应用。微细电火花加工技术由于其无加工机械作用力、可加工难切削导电材料、加工精度高等特点,在微细群孔结构零部件的加工中具有很大的优势。微细群孔的加工精度影响着该类零件的使用效果及工作寿命,而工作液条件及电极损耗是影响微细群孔加工精度的重要因素,因此研究微细群孔电火花的工作液条件及电极损耗具有重要意义。本文首先论述了国内外微细群孔加工的研究现状,分析了微细群孔电火花加工各阶段的加工特点,并利用流体仿真软件建立了间隙流场的仿真模型,对各加工阶段的间隙流场的速度分布情况进行研究。针对间隙流场状态最为复杂的孔加工中间阶段,研究了冲液流量、电极转速和加工深度对间隙流场的速度分布影响规律。基于微细电火花加工系统的结构特点及工作原理,采用块电极磨削及线电极磨削相结合的方法制备出试验所需微细电极。为了选取合理的冲液流量及电极转速,对不同冲液流量及电极转速条件下的微细群孔电火花加工进行实验研究。当冲液流量增大时,被加工孔的孔径一致性及入口形貌质量得到明显改善,且微细孔的加工效率提高、电极损耗降低;当电极转速提高时,放电间隙的排屑能力增强,放电环境得到改善,并提高了微细孔加工的效率。该实验结果与加工间隙流场的仿真分析结论相符。为了选取适合于微细群孔加工的电源加工模式及电参数,在对微细电火花加工使用的多模式微能脉冲电源进行分析的基础上,开展了RC、TC、TR三种电源模式下的电参数加工工艺试验,得出不同电参数对工具电极损耗、加工效率及微细孔的放电间隙的影响规律。根据实验结论,在RC电源模式下,选取低电压及较大电容,能够获得较好的微细孔加工质量。在选取合适的电参数及相关加工参数后,对不同工件厚度及不同工具电极直径条件下的微细群孔电火花加工的电极损耗规律进行研究,得出在工具电极保持不变时,电极的轴向损耗随着加工工件厚度及加工孔数的增加,呈线性增长。根据该规律,对电极的损耗补偿策略进行研究,得出一种每孔均匀补偿的损耗补偿策略。为了验证该策略的有效性,分别以100μm和80μm直径电极进行微细群孔加工实验。
[Abstract]:With the rapid development of scientific research and industrial technology, micro-hole structure parts have been widely used. It has great advantages in the machining of micro group hole structure parts. The machining precision of micro group hole affects the working effect and working life of this kind of parts, and the working fluid condition and electrode loss are the important factors that affect the machining accuracy of micro group hole. Therefore, it is of great significance to study the working conditions and electrode loss of micro group hole EDM. Firstly, this paper discusses the research status of micro group hole machining at home and abroad, and analyzes the processing characteristics of each stage of micro group hole EDM. The simulation model of the clearance flow field is established by using the fluid simulation software, and the velocity distribution of the clearance flow field in each processing stage is studied. In the middle stage of the hole machining, the flow rate of the flushing fluid is studied, which is the most complicated state of the clearance flow field. The effect of electrode speed and machining depth on the velocity distribution of gap flow field is studied. In order to select the reasonable flow rate and rotating speed of the electrode, the micro electrode was prepared by the combination of block electrode grinding and linear electrode grinding. The experimental study on EDM with different flow rate and electrode speed was carried out. When the flow rate was increased, the pore diameter consistency and the quality of the inlet morphology were improved obviously, and the machining efficiency of the micro-hole was improved. The electrode loss is reduced, and the discharge gap is enhanced with the increase of electrode speed, and the discharge environment is improved. The experimental results are in agreement with the results of simulation analysis of the gap flow field. In order to select the power source machining mode and electrical parameters suitable for the micro-hole machining, the experimental results are in good agreement with the simulation results of the flow field in the machining gap. Based on the analysis of the multi-mode micro-energy pulse power supply used in micro-EDM, the experiments of electrical parameter processing under three power supply modes, RCU TCU TR, are carried out, and the electrode losses of tool are obtained with different electrical parameters. The effect of machining efficiency and discharge gap of micro holes. According to the experimental results, low voltage and large capacitance are selected in RC power supply mode. After selecting appropriate electrical parameters and relevant machining parameters, the electrode loss law of EDM with different workpiece thickness and tool electrode diameter is studied. When the tool electrode remains constant, the axial loss of the electrode increases linearly with the thickness of the workpiece and the number of holes. According to this law, the loss compensation strategy of the electrode is studied. In order to verify the effectiveness of this strategy, a loss compensation strategy with 100 渭 m and 80 渭 m diameter electrodes was developed.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG661

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