Precision wire electrochemical machining of thick structures in powder superalloy René 88DT using a partially insulated tube electrode

Abstract

Wire electrochemical machining (WECM) is a potential method for manufacturing macrostructures from difficult-to-cut materials, such as turbine slots, with good surface integrity and low costs. In this study, a novel tube electrode with array holes in the front and insulation in the back was applied using WECM to improve the machining precision and efficiency. Additionally, assisted by an immersion electrolyte and axial flushing, the electrolyte-deficient gap was supplemented to achieve the cutting of a very thick workpiece. The simulation results indicated that this method could effectively reduce the machining gap and improve the uniformity of the electric- and flow-field distributions. Experiments verified that when the uninsulated range (machining angle) was reduced from 360° to 90°, the side machining gap was reduced from 462.5 µm to 175 µm. Finally, using optimized machining parameters, array slits with gaps as small as (175±10) μm were machined on a powder superalloy René 88DT sample with a thickness of 10 mm at a feed rate of 16 µm/s. The feasibility of fabricating complex profiles using this method was verified using a self-designed servo device.

Keywords

Wire electrochemical machining (WECM) / Tube electrode / Partial insulation / Machining angle / Electrolyte flushing / Surface quality

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Funding

National Natural Science Foundation of China http://dx.doi.org/10.13039/501100001809(51975291)

Natural Science Foundation of Jiangsu Province http://dx.doi.org/10.13039/501100004608(BK20191279)