复杂结构件工序模型自动构建技术研究

工序模型动态集成了航天产品及其零部件的设计、工艺、制造等信息，工序模型构建是航天制造领域三维工艺设计的关键内容，可为控制航天器制造工艺状态、提高加工质量提供使能工具。首先，介绍了正向和逆向两类建模方法的技术原理与特点，将主要建模方法分为特征法、工艺信息法两类;其次，深入分析了切削体造型等不同技术方法的原理与特点;最后，总结了该技术的关键问题并展望其发展方向。本文可为今后航天结构件工序模型自动构建技术的研究提供理论指导与支持。     

Cooling and lubrication techniques in grinding:A state-of-the-art review,applications, and sustainability assessment

Grinding technology is an essential manufacturing operation, in particular, when a component with a superfinishing and an ultra-resolution is yearned. Meeting the required strict quality checklist with maintaining a high level of productivity and sustainability is a substantive issue. The recent paper outlines the lubrication and cooling technologies and mediums that are used for grinding. Furthermore, it provides a basis for a critical assessment of the different lubrication/cooling techniques ...     

Trajectory optimisation in electrical discharge machining of three-dimensional curved and twisted channels

Numerical control electrical discharge machining(NC EDM) is one of the most widely used machining technologies for manufacturing a closed blisk flow path, particularly for three-dimensional(3D) curved and twisted flow channels. In this process, tool electrode design and machining trajectory planning are the key factors affecting machining accessibility and efficiency. Herein, to reduce the difficulty in designing the electrode and its motion path in the closed curved and twisted channels, a heur...     

Electrochemical behavior of Ti-6.5Al-2Zr-1Mo-1V alloy under rotating condition with periodically fluctuating current density

Titanium alloy plays a crucial role in the electrochemical field due to its excellent corrosion resistance. The passivation and dissolution behaviors of Ti-6.5Al-2Zr-1Mo-1V（TA15） alloy in Na Cl solution were studied by simulating the electrochemical machining process in a rotating condition, which made the anode in a state with alternating high and low current density. Electron probe micro analysis, ultra-depth microscope, scanning electron microscope, and X-ray photoelectron spectrometer were u...     

Path,feedrate and trajectory planning for free-form surface machining: A state-of-the-art review

Nowadays, free-form surfaces have been widely used in various industrial fields. They are usually machined by CNC machine tools, but recently have also begun to be manufactured by industrial robotic arm manipulators, thanks to low cost, large operation reaching space and high machining flexibility of robot. So far, various methodologies have been proposed to improve efficiency and quality of free-form surface machining, thus this paper aims at providing a state-of-the-art review on research advances in free-form surface machining. In this review, tool path generation, feedrate scheduling in Cartesian space and trajectory planning in joint space are focused for both CNC machining and robot machining, and their research statues, existing difficulties and key issues are discussed in detail. Finally, the feasible routes, breakthrough points and future development trend are also expounded.     

Flow field design and experimental investigation of electrochemical machining on blisk

Flow field is a crucial factor to influence the stability and surface quality in the electrochemical machining (ECM) of blisks. A four-way flow mode was proposed to eliminate mixing regions of electrolyte at the leading and tailing edges. Two flow field models were described separately in this report: a W-shaped flow mode and a four-way flow mode. The flow field was analyzed through a finite element method. The results showed that, in comparison with the W-shaped flow mode, the distribution of electrolyte flow was more uniformed and the mixed region in the flow channel was improved. The pressure of the leading and tailing edges inlets was optimized, and optimal pressure of 0.6 MPa was determined. In addition, verification experiments were performed, and the results showed that the stability, efficiency, and quality of the profiles of the blisk blade manufactured by ECM were enhanced in the new flow mode.     

Optimization of flow field in electrochemical trepanning of integral cascades (Ti6Al4V)

Ti6Al4V is widely applied in the integral cascades of aero engines. As an effective machining method, electrochemical trepanning (ECTr) has unique advantages in processing surface parts made of hard-to-cut materials. In ECTr, the state of the flow field has a significant effect on processing stability and machining quality. To improve the uniformity of the flow field when ECTr is applied to Ti6Al4V, two different flow modes are designed, namely full-profile electrolyte supply (FPES) and edges electrolyte supply (EES). Different from the traditional forward flow mode, the flow directions of the electrolyte in the proposed modes are controlled by inlet channels. Simulations show that the flow field under EES is more uniform than that under FPES. To further enhance the uniformity of the flow field, the structure of EES is optimized by modifying the insulating sleeve. In the optimized configuration, the longitudinal distance between the center of the inlet hole and the center of the blade is 6.0 mm, the lateral distance between the centers of the inlet holes on both sides is 16.5 mm, the length to which the electrolyte enters the machining area is 1.5 mm, and the height of the insulating sleeve is 13.5 mm. A series of ECTr experiments are performed under the two flow modes. Compared with EES, the blade machined by FPES is less accurate and has poorer surface quality, with a surface roughness (R_a) of 3.346 μm. Under the optimized EES, the machining quality is effectively enhanced, with the surface quality improved from R_a = 2.621 μm to R_a = 1.815 μm, thus confirming the efficacy of the proposed methods.     

Breakthrough detection in electrochemical discharge drilling to enhance machining stability

Film cooling holes are widely used in aero-engine turbine blades. These blades feature large numbers of holes with complex angles and require a high level of surface integrity. Electrochemical discharge drilling(ECDD) combines the high efficiency of electrical discharge drilling(EDD) with high quality of electrochemical drilling(ECD). However, due to the existence of a variety of energy for material removal, accurate and timely detection of breakthroughs is fraught with difficulties. An insuffic...     

Investigation of anode shaping process during co-rotating electrochemical machining of convex structure on inner surface

A novel co-rotating electrochemical machining method is proposed for fabricating convex structures on the inner surface of a revolving part. The electrodes motion and material removal method of co-rotating electrochemical machining are different from traditional electrochemical machining. An equivalent kinematic model is established to analyze the novel electrodes motion,since the anode and cathode rotate in the same direction while the cathode simultaneously feeds along the line of centres. Acc...     

电化学加工机器人动态性能设计与优化研究

工业机器人工作空间大、姿态灵活、可配置性高，且成本低，广泛应用于搬运、装配、喷涂和焊接等多个领域。但由于机器人末端轨迹精度不高，低速波动大，在电化学加工领域的应用很少。根据电化学加工低速、高轨迹精度特点，提出采用象限法设定电化学加工机器人工作区域，建立电化学加工机器人动力学优化函数，采用第三代非支配遗传算法NSGA-Ⅲ求解各设计参数最优Pareto解集，通过仿真和实验进行了动态性能测试验证。结果表明在设定工作区域内，电化学加工机器人直线轨迹精度可达0.073 mm，圆弧轨迹精度可达0.145 mm，低速工况下轨迹精度相比传统工业机器人提高近10倍。