Study of Gas Film Characteristics in Electrochemical Discharge Machining and Their Effects on Discharge Energy Distribution

Abstract

Glass is a hard and brittle insulating material that is widely used in optics, biomedicine, and microelectromechanical systems. The electrochemical discharge process, which involves an effective microfabrication technology for insulating hard and brittle materials, can be used to perform effective microstructural processing on glass. The gas film is the most important medium in this process, and its quality is an important factor in the formation of good surface microstructures. This study focuses on the gas film properties and their influence on the discharge energy distribution. In this study, a complete factorial design of experiments (DOE) was used, with three factors and three levels of voltage, duty cycle, and frequency as the influencing factors and gas film thickness as the response for the experimental study, to obtain the best combination of process parameters that would result in the best gas film quality. In addition, experiments and simulations of microhole processing on two types of glass, quartz glass and K9 optical glass, were conducted for the first time to characterize the discharge energy distribution of the gas film based on the radial overcut, depth-to-diameter ratio, and roundness error, and to analyze the gas film characteristics and their effects on the discharge energy distribution. The experimental results demonstrated the optimal combination of process parameters, at a voltage of 50 V, a frequency of 20 kHz and a duty cycle of 80%, that achieved a better gas film quality and a more uniform discharge energy distribution. A thin and stable gas film with a thickness of 189 μm was obtained with the optimal combination of parameters, which was 149 μm less than the extreme combination of parameters (60 V, 25 kHz, 60%). These studies resulted in an 81 μm reduction in radial overcut, a roundness error reduced by 14, and a 49% increase in the depth–shallow ratio for a microhole machined on quartz glass.

Mechanism of electrochemical discharge machining on film cooling holes with thermal barrier coatings

“…Geng et al [13] proposed a back ush electrochemical discharge machining technique to address recast layers and fractures, resulting in high-quality lm cooling holes. Geng et al [14] investigated the recast layer and elemental distribution after lm cooling hole machining using ECDM, while Liu et al [15] examined gas lm purity and consistent discharge energy distribution with ECDM. Vasudevan et al [16] and Zhang et al [17] addressed issues like thermal spalling, delamination, aking, splattering, recast layers, and cracking on ceramic coatings, proposing that ECDM can mitigate these problems.…”

Experimental Study of Electrolytic Processing of Discharge-Assisted Jet Masks

“…Liu, H. and Xieeryazidan, A. [18] investigated the effect of energy distribution on electrochemical discharge machining, and experiments showed that the optimal combination of process parameters at 50 V voltage, 20 kHz frequency, and 80% duty cycle achieved a more uniform distribution of discharge energy, which was able to efficiently machine pairs of hard and fragile materials. Chuang et al [19] utilized the interaction of electrochemical and EDM compensating techniques for the machining of CrNiFe alloy material machining; the machining accuracy was characterized by electrical pulse signal matching, processing time was reduced by 80%, and the efficiency of the equipment was improved.…”