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.
Microchannels machining can be used to make micro molds for microfluidic chips. The fluid flow in the channel can be controlled, by changing the cross sectional shape of the channel. V-shaped channels with a specific angle are not easily made with the etching process. This study presents the mechanical machining of microchannels of V-shaped cross section, on cemented carbide (WC-Co). In this study, to reduce tool wear in the process of machining, the micro conical tool was fabricated using polycrystalline diamond (PCD). The tool wear of the conical tool and form accuracy of channels, were investigated during V-shaped microchannel machining.
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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
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
A femtosecond laser is used in various fields such as microscale machining, OLED repair, micro 3D structure fabrication, and eye surgery. Particularly, because of non-thermal property, ablation and ablation threshold are the most representative characteristics of femtosecond laser. The ablation system is accompanied by many optics, stage, or gantry. In the case of the gantry, an ordinary optic system delivers a beam where mirrors and lens are required. If the gantry moves to the sample, external stimulation such as vibration will occur. Vibration has an influence on optics such as transforming beam path and becomes an error that decreases accuracy, precision, and spatial resolution. Generally, Fiber Optic Beam Delivery System (FOBDS) is used to solve this issue. But in the case of the femtosecond laser, FOBDS is incompatible. Recently, another FOBDS model that is compatible with the femtosecond laser has been developed. In this paper, the ablation threshold was obtained by FOBDS and femtosecond laser. The results present a possibility of ablation without external stimulation.
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257 nm Deep UV Femtosecond Laser Ablation with Minimized Crack and Chipping on Display Ultra-Thin Glass Kwangwoo Cho, Junha Choi, Changdeok Ko, Muhyun Kim, Joohan Lee, Eunhyang Eom, Sung-Hak Cho International Journal of Precision Engineering and Manufacturing.2024; 25(2): 271. CrossRef
The tungsten carbide is a material with high hardness, wear resistance, good chemical stability, and dimensional stability. Because of these characteristics, it is mainly used as a tool for cutting and molding such as molds, and casts required for manufacturing high value-added equipment such as automobile parts and medical equipment. However, it is difficult to process with the traditional machining methods because of the high toughness and hardness. To overcome these problems, a study of tungsten carbide machining processing using the ultrafast-laser was recently conducted. In this paper, the ultrafast lasers with the pulse duration of 190 fs, 5 and 10 ps, respectively, were used. When the experiments were conducted with pulse widths of 5 and 10 ps, respectively, micro-cracks were observed from the heat generated by the overlap of the laser pulses. Conversely, the machining processing using a laser with the pulse width of 190 fs showed a major advantage with no crack by minimizing the thermal effects.
CFRP (Carbon fiber reinforced plastic) has been widely used in different industries such as aerospace, automobile, sports and medical. Laser processing of CFRP has a great potential for industrial applications. In this paper researched the micro cutting and drilling of CFRP with 0.5 mm thickness using 1064 nm ytterbium nanosecond pulsed fiber laser. It also investigated machining characteristics of micro cutting and drilling according to laser power, frequency, scan speed and number of scan (or irradiation). Complete cutting and through-hole drilling were achieved with low frequency when the laser power was low and with low and middle frequency when the laser power increased. However, those were not achieved a frequency of 100 kHz. The cutting width increased when the power increased and decreased when the frequency and the scan speed increased. The hole size increased when the power and the number of irradiation increased and decreased when the frequency increased. In the case of micro hole array, the hole was blocked during the next hole machining when the hole spacing was narrow. The resin was melted by the heat thus blocking the pre-drilled hole. We devised the laser scan method, and the micro hole array with narrow hole spacing was fabricated successfully.
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Laser Drilling of Micro-Hole Array on CFRP Using Nanosecond Pulsed Fiber Laser Do Kwan Chung Journal of the Korean Society of Manufacturing Process Engineers.2024; 23(5): 92. CrossRef
Laser EDM Hybrid Micro Machining of CFRP Do Kwan Chung, Chan Ho Han, Yu Jin Choi, Jun Seo Park Journal of the Korean Society for Precision Engineering.2023; 40(2): 99. 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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