Blisk (bladed-disk) is one of the core components in the new generation aeroengine. And electrochemical machining (ECM) is one of the main manufacturing technologies for blisk. To address the problem of short circuit at the leading edge and trailing edge of the blade, a new immersed flow mode is proposed in electrochemical trepanning (ECTr) for blisk. The flow channel model of the new flow mode was established, and the dynamic simulation of the flow field was carried out. The simulation results showed, compared with the traditional flushing flow mode, the submerged ECM approach achieves a blade-edge flow velocity of 24 m/s in the immersed flow mode, reduces low electrolyte velocity points at the blade edge, and enhances the overall flow field unity. A closed electrolyte reservoir was designed to form a closed electrolyte aggregation pool to realize the immersed flow mode. Corresponding experiments were carried out in two flow modes for blisk made of GH4169G material. The results showed that the feed rate of the tool increased from 0.55 mm/min to 0.8 mm/min in the immersed flow mode compared with that in the flushing flow mode, and the machining stability, machining efficiency and surface quality of the blisk was significantly improved. This new flow mode can also be applied to manufacture casings, diffusers, and other complicated components in aerospace engines.

Electrochemical trepanning (ECTr) is an effective electrochemical machining (ECM) technique that can be used to manufacture the integral components of aero-engine compressors. This study focused on the dynamic evolution of ECTr for production of inner blisks (bladed disks) with a special chamfer structure at blade tip. Due to the existence of chamfer, the ECTr process of inner blades is in a non-equilibrium state during the early stages, and the physical field changes in the machining gap are complex, making it difficult to predict the forming process. In this paper, a dynamic evolution model (DEM) of inner blade ECTr with a special chamfer at blade tip structure is proposed, and an ECTr multi-physical fields simulation study was carried out. The evolution of the chamfer at blade tip was analyzed and data related to chamfer were predicted based on the dependence of anode boundary properties with machining time and feed rate. In addition, the distributions of current density, electrolyte flow rate, bubble volume fraction, temperature rise, and electrolyte conductivity in the machining area at different times were obtained by combining them with the multi-physical fields simulation results. Subsequently, a series of ECTr experiments were conducted, in which, as the feed rate increased, the surface quality and machining accuracy of the inner blades were improved. Compared with the simulation results, the error in machining accuracy of the chamfer profile is controlled within ± 2%, and the machining accuracy of the blade full profile was controlled within ± 0.2 mm, indicating that the model proposed in this study was effective in predicting the evolution of inner blades ECTr with chamfer structures at blade tip.

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.

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.