微细型腔密集结构的电火花加工精度保障技术研究

The stability and reliability of dense micro-cavity structure machining accuracy in micro-EDM are the bottleneck of its industrialization and application. A research on guaranteeing precision of micro cavity machining in micro-EDM has been advanced. The technology of precision positioning, reliable clamping for rotating micro-electrode, the micro actuation technology, the online creep feed compensation technology have been adopted to develop micro rotating electrode online creep feed compensation precision air spindle device and its control system, and it can solve the technology blockade and embargo of developed countries to our country. In the field of pulse power, a high precision micro pulse power should be developed to satisfy the demands of micro cavity machining. The floating threshold detection technology and the characteristics of discharge gap for this micro pulse power also have been studied. The dielectric properties and flow field characteristics of working liquid which should be studied have great influences on accuracy of micro cavity machining and micro electrode grinding. And the same time, the project carries on a large number of experiments to study the method of micro cavity machining, and gains the loss law of array cavity in micro-EDM. And then, a loss model is established to help study the wear compensation of micro electrode. After these, we can improve and guarantee the machining accuracy of micro electrode and dense micro-cavity structure..The research on accuracy guarantee of dense micro-cavity structure machining in micro-EDM which the project will do enhances the industrial technical level and research & development ability in the field of micro cavity machining and micro nano manufacturing, and it might widely promote the micro cavity densely distributed structure parts’ application. All the advantages point that the project has a profound and far reaching significance.

微细型腔密集结构电火花加工精度的稳定性和可靠性是制约其实用化产业化和应用范围的技术瓶颈。本项目针对这一技术瓶颈，开展微细型腔密集结构的电火花加工精度保障技术研究。主要研究微细旋转电极的精密定位、可靠夹持、微驱动以及在线蠕动进给补偿技术，研制微细旋转电极在线蠕动进给补偿精密气浮主轴装置及其控制系统，解决发达国家对我国技术封锁和禁运问题；研究高精度微能脉冲电源技术、浮动阈值放电状态检测技术和放电间隙特性；研究工作液介电特性及其流场特性对微细电极和微细型腔加工精度的影响；研究微细型腔密集结构的电火花加工工艺和电极损耗规律，建立其损耗数学模型，研究电极损耗补偿技术，以提高和保障微细工具电极和微细型腔密集结构的加工精度。.本项目开展的微细型腔密集结构电火花加工精度保障技术研究，对提高我国微细型腔电火花加工技术的研究水平，拓宽微细型腔密集结构的应用领域，促进微纳制造业的发展，具有十分重要的现实意义。

随着科学技术的快速发展，对具有微细型腔密集结构的关键零部件与微机电系统的需求日趋迫切，对影响微细型腔密集结构加工精度的因素进行全面系统的研究，有利于保障微细型腔密集结构电火花加工精度的稳定性和可靠性。项目研制了集微细旋转电极的可靠定位夹持和在线蠕动进给补偿功能于一体的精密主轴，提高微细电极回转运动的定位精度，保障微细型腔密集结构电火花加工的精度。研究了多模式高精度微能脉冲电源技术，可根据加工需要切换电源模式，保证脉冲电源能量的可控稳定输出，实现粗、中、精加工功能。项目对火花放电间隙特性进行了研究，根据间隙特性研制出一种基于浮动阈值放电状态检测的自适应伺服进给系统和单脉冲放电式非接触感知定位控制系统，实现放电状态的稳定、快速、准确检测，加工间隙放电的稳定控制和电极相对工件表面的精密定位。项目研制了集主动供丝和电极丝恒速、恒张力控制等功能于一体的微细电极磨削系统，建立电极加工直径精度预测模型，实现微细电极的高效、高精度制备。项目研究了工作液介电特性及间隙流场对微细型腔密集结构加工精度的影响规律，研制出一套工作液循环供给系统，并优化了加工冲液条件。项目建立了微细型腔密集结构电火花加工电极损耗数学模型，并结合CCD视觉观测系统实现了电极损耗的在线补偿功能。利用研制的脉冲电源、微细电极制备和自适应伺服进给调节等技术搭建了微细型腔密集结构加工试验装备及控制系统。利用该装备进行了工艺试验，分别对微细群孔、微细阶梯孔、微细阵列型腔和三维表面微织构进行了加工试验，成功加工出了数量≥256、目标直径分别为45μm、30μm、20μm的微细群孔，孔径偏差≤2μm；数量≥100、深径比≥2的阵列阶梯孔；数量≥50、一致性精度≤1.5μm的阵列型腔；SERS增强因子＞10^7的三维表面微织构。项目执行期间共发表论文10篇，其中SCI检索6篇，参加学术会议8人次，培养博士研究生6人，硕士研究生14人，相关研究成果获得了中国机械工业科学技术发明三等奖。