Experimental investigations into the performance of die-sinking mixed-gas atomization discharge ablation process on titanium alloy

Abstract

As a variant of highly efficient electrical discharge machining (EDM), the die-sinking mixed-gas atomization discharge ablation process (DMA-DAP) uses an atomized dielectric formed by a mixed gas, which mainly composed of oxygen and supplemented by nitrogen, and water medium as the discharge medium. In this technology, the oxygen in the medium is used for exothermic oxidation, and the vaporization and explosion of the water generates a chip removal force for highly efficient erosion. The present work uses single-factor tests to compare the characteristics of processing the difficult-to-machine material titanium-alloy special-shaped cavities using either DMA-DAP or EDM. The current, pulse width, pulse interval, and dielectric pressure are selected as the single-factor processing parameters, and how they influence the material removal rate (MRR), electrode relative wear rate (ERWR) and the surface morphology of the processed square cavities is analyzed. The results show that with DMA-DAP, the MRR is more than 12 times that of EDM, the ERWR is reduced by more than 98%, and the surface morphology is relatively good. Finally, taking an aero-engine radial diffuser as the profiling object, DMA-DAP realizes a profiling sample in the form of a variable-cross-section cavity that EDM cannot process, and the efficient die-sinking processing ability of DMA-DAP is verified.