A study of electrodischarge machining–pulse electrochemical machining combined machining for holes with high surface quality on superalloy

Abstract

Noncircular holes on the surface of turbine rotor blades are usually machined by electrodischarge machining. A recast layer containing numerous micropores and microcracks is easily generated during the electrodischarge machining process due to the rapid heating and cooling effects, which restrict the wide applications of noncircular holes in aerospace and aircraft industries. Owing to the outstanding advantages of pulse electrochemical machining, electrodischarge machining-pulse electrochemical machining combined technique is provided to improve the overall quality of electrodischarge machining-drilled holes. The influence of pulse electrochemical machining processing parameters on the surface roughness and the influence of the electrodischarge machining-pulse electrochemical machining method on the surface quality and accuracy of holes have been studied experimentally. The results indicate that the pulse electrochemical machining processing time for complete removal of the recast layer decreases with the increase in the pulse electrochemical machining current. The low pulse electrochemical machining current results in uneven dissolution of the recast layer, while the higher pulse electrochemical machining current induces relatively homogeneous dissolution. The surface roughness is reduced from 4.277 to 0.299 mm, and the hole taper induced by top-down electrodischarge machining process was reduced from 1.04°to 0.17°after pulse electrochemical machining. On account of the advantages of electrodischarge machining and the pulse electrochemical machining, the electrodischarge machining-pulse electrochemical machining combined technique could be applied for machining noncircular holes with high shape accuracy and surface quality.

Cathode structure optimization and process experiment in electrochemical machining of multi-stage internal cone hole

“…Electrochemical machining (ECM) has the advantages of one-time forming, high processing efficiency, good surface quality and no loss of cathode in theory, which determines that ECM is one of the effective methods to realize the machining of conical hole structure parts [8][9][10][11][12]. For processing technology，Ma et al fabricated the non-circular hole structure on the surface of turbine rotor blade by using the combined electrical machining technology [13]. Sathish used the injector nozzle to drill micro holes in pure stainless steel.…”

Research on Multi-Physics Coupling Simulation for the Pulse Electrochemical Machining of Holes with Tube Electrodes

“…Manpreet [ 21 ] obtained the optimal direct current voltage suitable for ECM of silicon wafers by taking overcut and taper as the output quality characteristics. Ma et al [ 22 ] used the pulse electrochemical method to optimize the surface roughness of non-circular holes after EDM, which was decreased from 4.227 μm to 0.229 μm.…”