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.
Keywords: core leach; surface roughness; ultra-fine and ultra-long copper tube electrode; ultrasonic high-frequency percussion; ultrasonic high-frequency percussion equipment.