Fabrication of Microgrooves by Synchronous Hybrid Laser and Shaped Tube Electrochemical Milling

The fabrication of deep microgrooves has become an issue that needs to be addressed with the introduction of difficult-to-cut materials and ever-increasing stringent quality requirements. However, both laser machining and electrochemical machining could not fulfill the requirements of high machining efficiency and precision with good surface quality. In this paper, laser and shaped tube electrochemical milling (Laser-STEM) were initially employed to fabricate microgrooves. The mechanisms of the Laser-STEM process were studied theoretically and experimentally. With the developed experimental setup, the influences of laser power and voltage on the width, depth and bottom surface roughness of the fabricated microgrooves were studied. Results have shown a laser power of less than 6 W could enhance the electrochemical machining rate without forming a deep kerf at the bottom during Laser-STEM. The machining accuracy or localization of electrochemicals could be improved with laser assistance, whilst the laser with a high-power density would deteriorate the surface roughness of the bottom machining area. Experimental results have proved that both the machining efficiency and the machining precision can be enhanced by synchronous laser-assisted STEM, compared with that of pure electrochemical milling. The machining side gap was decreased by 62.5% while using a laser power of 6 W in Laser-STEM. The laser-assistance effects were beneficial to reduce the surface roughness of the microgrooves machined by Laser-STEM, with the proper voltage. A laser power of 3 W was preferred to obtain the smallest surface roughness value. Additionally, the machining efficiency of layer-by-layer Laser-STEM can be improved utilizing a constant layer thickness (CLT) mode, while fabricating microgrooves with a high aspect ratio. Finally, microgrooves with a width of 1.79 mm, a depth of 6.49 mm and a surface roughness of 2.5 μm were successfully fabricated.

Plane Machining by Inner-Jet Electrochemical Milling of TiB2/7050 Aluminum Matrix Composite

Electrochemical milling (ECM) is an ideal technique for machining thin-walled structural parts of aluminum matrix composites. Adopting a reasonable tool cathode structure, feed rate, and processing method can improve the machining efficiency. In this study, a tool cathode with a reasonable structure was selected through flow field simulation. Then, the material removal rate (MRR) and surface roughness were studied using various ECM parameters. Finally, the transverse movement and processing method in which the starting position was rotated 90° were studied, and a plane of 59 × 59 mm was machined. The experimental results show that using an appropriate tool cathode can create a more uniform flow field. The MRR was 168.6 mm3/min and the surface roughness (Ra) was 3.329 µm at a feed rate of 30 mm/min. For machining larger plane structures, a transverse movement of 7 mm is verified to be the most suitable because of the best smoothness in the middle of the two processes. By using the same machining method and rotating the starting position 90°, the flatness of the processing plane decreased from 0.296 mm to 0.251 mm, a reduction of 15.2% compared to that obtained in the first processing.

Micro Electrochemical Milling of Micro Metal Parts with Rotating Ultrasonic Electrode

With the rapid development of MEMS, the demand for metal microstructure is increasing. Micro electrochemical milling technology (MECM) is capable of manufacturing micro metallic devices or components based on the principle of electrochemical anode dissolution. To improve the capacity of MECM, this paper presents a compound method named ultrasonic vibration-assisted micro electrochemical milling technology (UA-MECM). Firstly, the simulation and mathematical model of UA-MECM process is established to explain the mechanism of ultrasonic vibration on micro electrochemical milling. Then, the effects of ultrasonic parameters, electrical parameters and feedrate on machining localization and surface quality are discussed considering sets of experiments. The surface roughness was effectively reduced from Ra 0.83 to Ra 0.26 µm with the addition of ultrasonic vibration. It turns out that ultrasonic vibration can obviously improve machining precision, efficiency and quality. Finally, two- and three-dimensional microstructures with good surface quality were successful fabricated. It shows that ultrasonic vibration-assisted electrochemical milling technology has excellent machining performance, which has potential and broad industrial application prospects.