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The integral shrouded blisk provides better performance with minimum weight, but its semi-open structure presents problems for its production. Manufacturing processes of these components require a removal of about 70%-90% of material from their blanks. Multi-axis electrical discharge machining (EDM) is commonly used for these processes, but its poor efficiency cannot meet the requirements of mass production. Strong flushing assisted high-current discharge is able to improve the machining efficiency. In this paper, this method was applied to manufacture the integral shrouded blisk. An electrode design method was proposed. Taking the largest revolving entity inside the flow channel as the base geometry, this laminated arc-shaped hollow electrode meets the requirements such as high pressure flushing, tool wear compensation, and easy to be made. A 4-axis linkage machining tool path with planetary motion was proposed. Taking an integral guide vane ring as an example, it has been experimentally verified that the time consumption for each channel using this method was reduced to a half of the ordinary EDM method, while the finished surface quality remains same.

An integrated method of micro-milling and micro electrical discharge machining (EDM) is proposed for micro-structures array manufacture in this paper. In order to obtain micro-cavity array with high accuracy and consistency, in situ machining on the same coordinate system ensures the positioning precision. After studying micro-milling graphite, the effect of parameters on the machining accuracy is found. Further, suitable mode is chosen for high-dimensional consistency and good surface quality array electrodes according to comparison of one-by-one and layer-by-layer milling tool trajectory. Workpiece lifting control is used to strengthen the debris clear; then, it is verified beneficial of lifting through flow simulation and adding discrete particles. In order to solve poor precision of the micro-cavity contour caused by electrode wear, a multi-step machining by group electrodes is proposed, rough machining for material removal and finishing machining for trimming. Finally, a micro-cavity with clear edge, small fillets, and high shape accuracy is obtained. This method improves the machining performance of the array micro-structures and shows good prospects in micro-fabrication.

Electro-arc machining (EAM) is a promising method in aerospace industry for its outstanding material removal efficiency. Compared with the traditional process, this method can easily machine high hardness and high melt point alloy such as titanium alloy and Nickel-base superalloy. In Electro-arc machining, hydrodynamic arc-breaking mechanism is a vital approach to achieve a continuous and efficiency process. The flushing pressure has a big influence on the integrity of the surface and the efficiency of whole process. In this paper, the influence of flushing in different tool orientation has been investigated using Ti6Al4V workpiece and deionized water. Using successive electro-arc pulse discharge, experiments under different tilt angle between the tool and workpiece were conducted. The discharge craters’ morphology on the workpiece are analyzed to disclose the coupling effect between high pressure flushing and tool tilt angle. It is found that colored anodized area of processed titanium surface is smaller with the increase of the flushing pressure, and its shape varies according to the tilt angle. This phenomenon indicates that flushing pressure and tool orientation determines the discharge by affecting the gap cooling condition and electric field distribution.

Using water-based dielectrics and high-energy density electrical discharge machining for titanium alloy and superalloy has shown promising economic advantages. Combined with sinking-EDM, its finishing quality can be further enhanced. However, the relatively high tool wear rates restrict the use of water-contained working fluid in sinking-EDM. As EDM is widely used for the machining of slots and holes, it is necessary to study the tool wear in these situations. In this paper, the mechanism of electrode loss is studied in 6 kinds of dielectrics, including EDM oil, WEDM working fluid, tap water, deionized water, emulsion, and polyethylene glycol solution. Two kinds of graphite materials were compared to explain the tool wear mechanism. Electrolysis consumption and discharge erosion were evaluated by experiments. The aim of this study is analyzing the effect of electrolysis and spark explosion on the performance of tool wear as well as their relation with dielectric characteristics. According to slot machining and electrode electrolysis experiments, carbon content and conductivity are regarded as the main influence factors. It is found that the dielectrics with higher carbon content can effectively reduce the tool wear in the machining process and electrolysis can lead to thinning of the electrode which makes it crumbly. This work can help compound suitable dielectrics and choose appropriate graphite electrode materials with lower tool wear in EDM machining.

EDM is an effective method for deep and narrow slot machining. The high aspect ratio blind slot can be machined with jump motion and vibration assistance. The decrease in machining accuracy and actual depth caused by electrode consumption in this process are currently common problems. Using oil-based working fluids, graphite electrodes have different wear and deposition patterns under different conditions. This study aims to control the final geometric accuracy of deep and narrow slot machining by optimizing electrical parameters. Experiments using orthogonal design were conducted with a 20×1×20mm narrow slot. The combined influences of parameters on the electrode geometry evolution are concluded. The peak current and duty factor are the main factors affecting the pattern of electrode tip geometry. Experiments were carried out to analyse the wear pattern corresponding to different levels of these two factors. The locations where deposition and wear are prone to occur are found to be the edge of the electrode tip. Parameters combinations capable of stably maintaining the shape of the electrode end are found. The results showed the feasibility of adjusting the tip wear pattern. Thus the final geometric precision of the slot machining can be controlled by adopting apposite parameters.

By introducing the mechanical motion into the confined etchant layer technique (CELT), we have developed a promising ultra-precision machining method, termed as electrochemical mechanical micromachining (ECMM), for producing both regular and irregular three dimensional (3D) microstructures. It was found that there was a dramatic coupling effect between the confined etching process and the slow-rate mechanical motion because of the concentration distribution of electrogenerated etchant caused by the latter. In this article, the coupling effect was investigated systemically by comparing the etchant diffusion, etching depths and profiles in the non-confined and confined machining modes. A two-dimensional (2D) numerical simulation model was proposed to analyze the diffusion variations during the ECMM process, which is well verified by the machining experiments. The results showed that, in the confined machining mode, both the machining resolution and the perpendicularity tolerance of side faces were improved effectively. Furthermore, the theoretical modeling and numerical simulations were proved valuable to optimize the technical parameters of the ECMM process.