切入式高效电解铣削加工技术基础研究

The aerospace products use a large number of large-size monolithic components with difficult-to-cut materials to meet demands for high reliability, low-energ and long-range. Because of the complex structures and large machining allowance, there are low efficiency, high cost and long production cycle during machining of these components. Electrochemical milling proposes an ideal way to process the large-size monolithic components, with high flexible, high efficiency and low cost. This project will systematically study the machining characteristics of plunge electrochemical milling with a rotating tool cathode, with the purpose of achieving the face-side compound forming and big machining allowance removal of monolithic components with difficult-to-cut materials. The flow characteristics of non-equilibrium electrolyte, the mechanism of face-side compound forming and the evolution mechanism of anode passivation-dissolution interfaces will be investigated in the machining process. Key technologies, such as the tool cathode design, processing path planning, the effects of auxiliary anode and nozzle will be broken through. The effects of various factors on the machining performances of electrochemical milling of difficult-to-machine materials will be reached. This project will provide an efficient machining method of large-size monolithic components with difficult-to-cut materials.

为满足航空航天产品“高可靠、低能耗、长航程”等性能要求，难加工材料大型整体结构件被广泛应用。该类零件结构复杂，材料去除量大，加工效率低、成本高、周期长。电解铣削加工是一种高柔性、高效率、低成本的制造技术，特别适合于航空航天难加工金属材料大型结构零件的制造领域。本项目将系统研究旋转工具阴极切入式电解铣削加工技术，以难加工材料结构件底面-侧面复合成型和大余量去除为目标，重点解决电解铣削加工过程中非平衡态电解液流动状态表征、多场耦合电解铣削加工底面-侧面复合成型机理、材料电化学溶解阳极钝化界面-溶解界面演化机制等基础理论问题，突破基于流场和电场的工具阴极设计、随动式柔性辅助阳极及辅助喷液对电解铣削加工过程的作用机制、基于结构特征的电解铣削加工路径规划等关键技术，掌握切入式电解铣削加工技术的加工工艺规律，实现难加工金属材料大型结构零件的高品质加工，丰富其加工手段。

针对难加工材料的高效大余量去除难点，本项目深入开展了切入式电解铣削加工技术研究。明确了切入式电解铣削加工非平衡态电场及流场周期性变化规律，阐明了不同侧壁出液孔布局下电流密度及电解液流速分布状态。开展了切入式电解铣削加工侧面及底面成型机理研究，揭示了二次电解作用对侧面及底面不均匀溶解的影响机制。在上述理论上，开展了基于电场及流场的提高加工效率的工具出液孔布局设计，提出了侧壁出液孔螺旋排布、侧壁出液孔数量最佳值求解和增设底面出液孔等方法，获得了多种显著提高加工效率的工具结构。通过对钛合金电化学溶解特性分析，掌握了钛合金高效电化学溶解规律，确定了钛合金加工工艺参数范围。探究了薄壁、腔体等多种特征结构的加工工艺规划，结合试验获得的最优电解加工参数，完成了多种典型结构的高效大余量加工。