Glassy carbon (GC) has superior properties such as high corrosion resistance, heat resistance, and low adhesion to glass materials in a glass molding process (GMP). In addition, the demand for GC molds is increasing in various industries that require high precision of glass parts. However, GC is a difficult-to-machine material with high hardness and brittleness. Electrical discharge machining (EDM) can machine GC regardless of its strength or hardness. In this study, tungsten carbide (WC-Co) electrode was fabricated by wire electrical discharge grinding (WEDG). Characteristics of EDM of micro holes on GC were then analyzed. As capacitance and voltage increased, material removal rate (MRR) increased while machining time tended to decrease. However, at low voltages, short circuit and secondary discharge occurred, which increased the electrode wear rate (EWR). As a result, a D-shaped electrode that could prevent short circuit and debris accumulation was fabricated and a micro hole array was machined.
CNN is one of the deep learning technologies useful for image-based pattern recognition and classification. For machining processes, this technique can be used to predict machining parameters and surface roughness. In electrical discharge machining (EDM), the machined surface is covered with many craters, the shape of which depends on the workpiece material and pulse parameters. In this study, CNN was applied to predict EDM parameters including capacitor, workpiece material, and surface roughness. After machining three metals (brass, stainless steel, and cemented carbide) with different discharge energies, images of machined surfaces were collected using a scanning electron microscope (SEM) and a digital microscope. Surface roughness of each surface was then measured. The CNN model was used to predict machining parameters and surface roughness.
Recently, the demand for micromachining of hard materials has been increasing. Machining microholes, grooves, and structures in hard materials such as tungsten carbide is very difficult. In this study, the machining characteristics of a microdisk tool for microgroove machining of tungsten carbide were studied. Microtools made of polycrystalline diamond (PCD) were fabricated using wire electrical discharge grinding (WEDG) to machine high-hardness tungsten carbide. Rectangular and V-shaped disk tools were fabricated by WEDG with controlled wire paths. In the micro grooving of tungsten carbide, the effects of capacitance and feedrate on the surface roughness of microgrooves and the wear of disk tools were studied. As the capacitance and feed rate decreased, the surface roughness decreased and no significant wear was observed in the PCD tool. However, an increase in tool edge radius of several micrometers was observed.
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Micro Hole Machining Characteristics of Glassy Carbon Using Electrical Discharge Machining (EDM) Jae Yeon Kim, Ji Hyo Lee, Bo Hyun Kim Journal of the Korean Society for Precision Engineering.2025; 42(4): 325. CrossRef
Prediction of Machining Conditions from EDMed Surface Using CNN Ji Hyo Lee, Jae Yeon Kim, Dae Bo Sim, Bo Hyun Kim Journal of the Korean Society for Precision Engineering.2024; 41(11): 865. CrossRef
In this study, a wire electrical discharge milling electrode was developed, and electric discharge machining characteristics were studied by using the electrode. The wire electrical discharge milling electrode is a form, in which the wire is conveyed by using a cylindrical rod with a hemispherical end as a guide, and it also rotates in one direction around the guide axis. If the wire electrical discharge milling electrode is used in electrical discharge machining (EDM), there is no need to consider electrode wear compensation. The EDM characteristics according to capacitance of the RC circuit and the rotational speed of the wire electrical discharge milling electrode were examined. The machining conditions were selected, and a hemispherical shape with good shape accuracy and fine surface finish was fabricated in two stages of roughing and finishing. By applying the wire electrical discharge milling electrode to the electric discharge milling process, straight and curved shapes were successfully machined.
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Experimental study on the wire electrical discharge machining of PCD with different grain sizes Kechuang Zhang, Laifa Zhu, Zhongwei Chen, Jianyun Shen, Xuefeng Zhao, Xian Wu Diamond and Related Materials.2025; 155: 112331. CrossRef
Silicon carbide (SiC) has been used as a material for semi-conductor, molds, and micro-electro-mechanical systems (MEMS) because of its superior thermal, electrical, and mechanical properties. However, micro machining of SiC is very challenging due to its hardness and brittleness. This paper presents an experimental study of micro hole drilling of SiC. In this study, polycrystalline diamond (PCD) was used as a tool to overcome the hardness of SiC. The micro PCD tool with a diameter of 110 μm was fabricated by micro electrical discharge machining (EDM). Micro drilling was conducted with varying machining parameters such as tool rotational speed and feed rate. Effects of surface roughness of the tool and lubrication method were also investigated.
Citations
Citations to this article as recorded by
Micro Hole Machining Characteristics of Glassy Carbon Using Electrical Discharge Machining (EDM) Jae Yeon Kim, Ji Hyo Lee, Bo Hyun Kim Journal of the Korean Society for Precision Engineering.2025; 42(4): 325. CrossRef
Prediction of Machining Conditions from EDMed Surface Using CNN Ji Hyo Lee, Jae Yeon Kim, Dae Bo Sim, Bo Hyun Kim Journal of the Korean Society for Precision Engineering.2024; 41(11): 865. CrossRef
Machining Characteristics of Micro EDM of Silicon Carbide Ju Hyeon Lee, Chan Young Yang, Bo Hyun Kim Journal of the Korean Society for Precision Engineering.2024; 41(2): 131. CrossRef
Study on Micro Grooving of Tungsten Carbide Using Disk Tool Min Ki Kim, Chan Young Yang, Dae Bo Sim, Ji Hyo Lee, Bo Hyun Kim Journal of the Korean Society for Precision Engineering.2024; 41(2): 123. CrossRef
EDM Using Wire Electrical Discharge Milling Electrode Do Kwan Chung Journal of the Korean Society for Precision Engineering.2022; 39(1): 21. CrossRef
High aspect ratio-arrayed micro structures are used in various fields such as semiconductor packaging, biochip, nano composite material and superhydrophobic surface. Micro electric discharge machining (MEDM) has an advantage, in that hard material can be easily removed regardless of mechanical properties of the material. Reverse micro electric discharge machining (REDM) can process various shapes and arrayed features. In this study, REDM was used for fabrication of a micro tool of eccentric shape, and was assisted with vibration to improve machining efficiency. The bored plate made of brass, was prepared as a tool for REDM. Because of the shape of the tool, concentration of debris occurs and increases machining time. The effect of vibration-assisted MEDM on emission of debris and machining time was described for the range of 2 - 6 μm amplitudes and of 100 - 900 Hz frequencies. As a result, vibration applied on machining reduces approximately 55% of machining time.
Citations
Citations to this article as recorded by
Micro Hole Machining Characteristics of Glassy Carbon Using Electrical Discharge Machining (EDM) Jae Yeon Kim, Ji Hyo Lee, Bo Hyun Kim Journal of the Korean Society for Precision Engineering.2025; 42(4): 325. CrossRef
Study on Micro Grooving of Tungsten Carbide Using Disk Tool Min Ki Kim, Chan Young Yang, Dae Bo Sim, Ji Hyo Lee, Bo Hyun Kim Journal of the Korean Society for Precision Engineering.2024; 41(2): 123. CrossRef
Machining Characteristics of Micro EDM of Silicon Carbide Ju Hyeon Lee, Chan Young Yang, Bo Hyun Kim Journal of the Korean Society for Precision Engineering.2024; 41(2): 131. CrossRef
Micro Drilling of Single Crystal SiC Using Polycrystalline Diamond Tool Ui Seok Lee, Chan Young Yang, Ju Hyeon Lee, Bo Hyun Kim Journal of the Korean Society for Precision Engineering.2021; 38(7): 471. CrossRef
Micro Pin Fabrication of Tungsten Carbide Using Polycrystalline Diamond Joo A Park, Ui Seok Lee, Bo Hyun Kim Journal of the Korean Society for Precision Engineering.2020; 37(11): 791. CrossRef
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