Influence of hybrid laser and shaped tube electrochemical machining by using retracted electrode

The machining stability and electrode feeding rate in the shaped tube electrochemical machining (STEM) process was limited by the formation of central residual. Laser-STEM combined the advantages of STEM and water-guided laser machining to enhance the materials removal rate (MRR) and precision, to some extent. In this study, a retracted hybrid tubular electrode was applied to make the MRR between the different machining regions homoplasy. Simulation results showed that the electric current density distribution homogeneity could be improved with the inner low-refractive layer retracted, and got an increase of 38% with a retracted length deg of 2 mm. W-shaped residual in the central machining area could be removed. When the retracted length deg increased from 0 mm to 2 mm, the laser coupling efficiency exceeded 74.5%. Hence, the retracted hybrid tubular electrode could act as both the tool electrode and optical waveguide in the Laser-STEM process. Experiment results confirm the simulation results and showed a significant improvement in machining efficiency and precision by utilizing the retracted hybrid tubular electrode. With the retracted length deg rising from 0 mm to 1.5 mm, the residual height showed a reduction of 72.6% in the STEM process. In the Laser-STEM process, the residual height decreased by 53.8% and 111% with the laser power of 6 W and 10 W, respectively.