Inconel 718 offers high oxidation resistance, mechanical strength, and heat resistance, which enables turbofan engines to maintain excellent performance in an operating environment of 1000°C. These properties make Inconel 718 difficult to machine by conventional machining techniques. Water jet guided laser (WJGL) is a composite processing technology that combines water cooling and laser processing technology. Therefore, it is advantageous and promising in processing Inconel 718. However, the water layer on the substrate surface in processing limits WJGL 's ability to ablate the metal, which leads to burrs formed when manufacturing groove structures. Therefore, a new method for manufacturing groove structure on Inconel 718 by Annular gas-assisted water jet guided laser (AGAWJGL) is proposed in this paper. This method reduces burrs and improves material removal efficiency by removing the water layer from the substrate surface with the gas-assisted. Then, groove processing experiment are performed on Inconel 718 alloy sheets with thickness of 1 mm. The experimental results show that the average size of burrs reduces 36%, and the depth of grooves increases 13%. These provide the theoretical foundation for the WJGL machining of Inconel 718.

In this study, the water-jet-guided laser (WJGL) method was used to cut Inconel 718 alloy with high temperature resistance. The effect of critical parameters of the water-jet-guided laser machining method on the cutting depth was studied by a Taguchi orthogonal experiment. Furthermore, the mathematical prediction model of cutting depth was established by the response surface method (RSM). The validation experiments showed that the mathematical model had a high predictive ability for cutting depth. The optimal cutting depth was obtained by model prediction, and the error was 5.5% compared with the experimental results. Compared with the traditional dry laser cutting, the water conducting laser method reduced the thermal damage and improved the cutting quality. This study provides a reference for the precision machining of Inconel 718 with a water-jet-guided laser.

In this study, a new method of ultrasonic high-frequency percussion (UH-FP) is proposed. Ultra-fine and ultra-long copper tube electrodes cannot be fabricated by traditional processing methods, and the copper tube electrodes fabricated by UH-FP can be used in the process of rotary EDM for microfine holes. The UH-FP setup has been established based on an ultrasonic device, a workpiece chucking and rotation device, and a workpiece reciprocating motion device. In this work, by studying the principle of ultrasonic processing, the processing principle and mechanism of ultra-fine and ultra-long copper tube electrode preparation by ultrasonic high-frequency percussion is proposed. The effects of processing parameters (i.e., rotational speed, feed rate, working gap, percussion amplitude) on surface roughness are evaluated quantitatively. Experimental results show that the proposed method could complete the core leach of the core-containing copper tube electrodes after drawing, while improving surface quality. Some surface defects such as cracks, scratches and folds were completed removed, further improving the mechanical performance of processed parts. The surface roughness (Ra) of 0.091 μm was obtained from the initial 0.46 μm under the optimal processing parameters of 800 rpm tube rotational speed, 200 mm/min platform feed speed, 0.13 mm machining gap, 0.15 mm percussion amplitude, and 32 min machining time. The method shows potential for manufacturing copper tube electrodes for a wide range of industrial applications.