Carbon fiber reinforced polymer (CFRP) is widely used in aerospace, machinery, and other fields because of its excellent mechanical properties, but defects such as fiber tearing can occur using conventional automated processing. EDM has proven the possibility of machining CFRP, therefore. In this paper, an experimental study on EDM of CFRP using graphene aqueous solution medium was conducted, and by comparing with kerosene and deionized aqueous solution discharge medium for CFRP, it was found that the MRR of CFRP by EDM of graphene aqueous solution was increased by 76% and 18%. The HAZ was reduced by 8% and 4%, respectively. The influence law of the electrical parameters of EDM on the MRR, EWR, and HAZ was investigated by the orthogonal test method, and the optimal machining parameter configuration was obtained by using gray correlation analysis to optimize the multi-objective parameters into a single-objective gray correlation. The feasibility of the obtained optimized parameters was verified by experiment.

Titanium alloy (Ti-6Al-4V) is a difficult-to-machine material, known for its excellent physical and chemical properties. However, traditional machining methods incur high tool wear costs when processing this material. The near-dry electrical discharge milling (N-EDM) method, which removes excess material via electroerosion, mitigates the impact of titanium alloy’s hardness and strength, enabling effective material cutting. To enhance machining efficiency and surface quality, this study employs a simulation model of the inter-electrode flow field, combined with experimental data, to investigate the effect of milling thickness on key machining parameters and determine the optimal thickness. Subsequently, a four-factor, three-level (L₂₇(4³)) orthogonal experiment was designed, with current, duty cycle, gas pressure, and atomization rate as input parameters. Material removal rate (MRR), relative electrode wear ratio (REWR), width of cut (WOC), and roughness average (R_a) were selected as primary optimization indicators. Based on the orthogonal experiment results, analysis of variance (ANOVA) was conducted to examine the influence of the input parameters on the various process indicators and determine the optimal single-objective processing parameters. Using Grey Relational Analysis (GRA), the multi-objective optimal machining parameters were identified as: 2 A current, 40% duty cycle, 0.2 MPa gas pressure, and 20 ml/min atomization rate. These parameters significantly enhance both processing efficiency and surface quality.

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.