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Micro total analysis systems: latest achievements.

Hybrid processes in manufacturing

Micro-electrochemical discharge machining (ECDM) was studied in order to improve the machining of 3D micro-structures of glass. To minimize structures and obtain good surface microstructures, the effects of the electrolyte, the pulse on/off-time ratio, the voltage, the feedrate, the rotational speed, and the electrolyte concentration in the drilling and milling processes were studied.In ECDM, voltage is applied to generate a gas film and sparks on a tool electrode; however, high voltage produces poor machining resolution. To obtain a stable gas film over the whole surface of the tool at a low voltage, a new mechanical contact detector, based on a loadcell, was used; the immersion depth of the tool electrode in the electrolyte was reduced as much as possible. In this study, various micro-structures less than 100 μm in size, such as O 60 μm micro-holes, a 10 μm-thin wall, and a 3D micro-structure were fabricated to demonstrate the potential for micro-machining of glass by ECDM.

Micro-structuring of glass with features less than 100 μm by electrochemical discharge machining

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Advanced Modeling and Optimization of Manufacturing Processes

Electrochemical discharge machining (ECDM) is a hybrid non-conventional machining process, used to machine electrically conductive and non-conductive materials. It is a preferred process to fabricate micro scale features like micro holes, micro channels, microgrooves and 3-dimensional intricate shapes on variety of materials. In order to improve the efficacy of ECDM process, certain technical augmentations are provided with basic configuration of ECDM. These augmentations result in developments of ECDM process variants. Further, research community has developed ECDM based triplex hybrid methods for further process enrichment. This review article presents a comprehensive review of these recent developments in ECDM process, its variants and their triplex hybrid methods. The future research possibilities are identified and presented as research potentials.

Developments in electrochemical discharge machining: A review on electrochemical discharge machining, process variants and their hybrid methods

Electrochemical discharge machining (ECDM) is demonstrated to be a potential process for 3D microstructuring of Pyrex glass. However, the key to widening ECDM micromilling applications lies in how to improve the machining accuracy. To improve the machining quality of the ECDM micromilling process, microgroove machining experiments were conducted in this study. Three factors affecting ECDM micromilling performance—pulse voltage, tool rotational rate and travel rate of tool—were taken up as machining parameters to investigate their influences on machining performance. The results indicate that optimum combinations of both pulse voltage and tool rotational rate will realize better machining accuracy. The feasibility of three-dimensional microstructure machining was demonstrated by layer-by-layer ECDM micromilling machining. Complex structures were made to demonstrate the great potential for the 3D microstructuring of Pyrex glass of the ECDM micromilling process.

http://iopscience.iop.org/article/10.1088/0960-1317/17/5/016/pdf

3D microstructuring of Pyrex glass using the electrochemical discharge machining process

Electrochemical discharge machining (ECDM) is found to be a potential process for the microdrilling of glass wafers. However, some degree of heat-affected zone resulting from the thermal energy during ECDM produces several inherent problems that might be major issues, such as over cut and taper hole. To improve the quality of the ECDM microhole, a flat sidewall–flat front tool electrode is designed to reduce taper phenomena due to the sidewall discharge. In addition, a pulse voltage is applied to improve the heat-affected zone in the rectified dc voltage. The experimental results show that the combination of flat sidewall–flat front tool and pulse voltage conspicuously increases the machining accuracy while retaining the machining rate. This experimental investigation provides a new method that overcomes the disadvantages of conventional ECDM.

https://iopscience.iop.org/article/10.1088/0960-1317/17/2/012/pdf

The tool geometrical shape and pulse-off time of pulse voltage effects in a Pyrex glass electrochemical discharge microdrilling process

Recently, the utilization of pulse voltage has proved to be a potential method for improving the machining accuracy in the microdrilling process by electrochemical discharge machining (ECDM). Although pulse voltage is favorable for improving the machining quality, it is hard to obtain an efficient machining rate. The pulse-off (Toff) duration allows the gas film structure to be re-constructed, which makes the sustainability of a dense gas film difficult and results in unstable and unpredictable discharges. In this study a novel pulse voltage configuration, called offset pulse voltage, has been designed and applied in the ECDM process to improve gas film stability. The offset pulse voltage adds a constant voltage, called offset voltage, at Toff duration to enhance gas film stability and to further promote the discharge performance. The experimental results demonstrated that the increase in offset voltage at the pulse-off duration generates more stable discharges when compared to those generated by the conventional pulse voltage. Results also show that both the mean machining time and time deviation are decreased around 60% without sacrificing machining accuracy by an adequate offset voltage.

https://iopscience.iop.org/article/10.1088/0960-1317/18/2/025014/pdf

Zhi Ping Zheng

Papers

3D microstructuring of Pyrex glass using the electrochemical discharge machining process

The tool geometrical shape and pulse-off time of pulse voltage effects in a Pyrex glass electrochemical discharge microdrilling process

Improving the machining efficiency in electrochemical discharge machining (ECDM) microhole drilling by offset pulse voltage