• Journal of the Korean Society for Precision Engineering
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• v.23 no.12 s.189
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• pp.111-116
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• 2006

Micro machining of tungsten carbide by electrochemical machining was studied. In ECM, machining conditions and electrolyte should be chosen carefully according to the property of workpiece materials. In this paper, sulfuric acid and nitric acid were used for tungsten carbide machining and machining characteristics were investigated according to machining conditions such as electrolyte, workpiece potential and applied pulse voltage. By using mixture of sulfuric acid and nitric acid, micro structures with sharp edge and good surface quality were obtained. Micro electrochemical turning was also introduced to fabricate micro shafts.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.992-995
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• 2001

Several evaluation methods of conventional machine tools have been proposed by KS and ISO. Even though the accuracy of the tools can be evaluated with those methods, there are still no proper evaluation method of high sped machining. Because it is hard to evaluate characteristics of high speed machining such as decrease of cutting temperature, cutting force, and reduced machining time. Therefore, new evaluation method for high speed machine should be developed. In this paper, several shape of model have been proposed to evaluate cutting accuracy of high speed machine.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1203-1206
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• 2003

After the micro turning lathe was developed in the last year by AMR Laboratory, a micro-milling machine is developed for micro machining. This machine is integrated with PZT-driven micro-sliders, micro-linear encoders, air turbine spindle which has maximum 150.000 rpm. It is applicable to milling and drilling machining. This paper shows the possibility of micro machining and characteristics of micro end milling process by using micro machine. A machining of micro barrier ribs using 0.2 mm flat type end mill was achieved by micro-milling machine. As experimental results show the machining capability and positional accuracy of this machine is good enough for machining micro parts.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.2
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• pp.1-6
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• 2012

Recent ultra-precision machining systems have nano-scale resolution, and can machine various shapes of complex structures using five-axis driven modules. These systems are also multi-functional, which can perform various processes such as planing, milling, turning et al. in one system. Micro machining technology using these systems is being developed for machining fine patterns, hybrid patterns and high aspect-ratio patterns on large-area molds with high productivity. These technology is and will be applied continuously to the fields of optics, display, energy, bio, communications and et al. Domestic and foreign trends of micro machining technologies for flat molds were investigated in this study. Especially, we focused on the types and the characteristics of ultra-precision machining systems and application fields of micro patterns machined by the machining system.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.8
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• pp.81-87
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• 1998

High-speed machining is one of the most effective technologies to improve productivity. Because of the high speed and high feedrate, high-speed machining can give great advantages for the machining of dies and molds. In this paper, high-speed machining for HP-4 die material was carried out with a coated tungsten carbide ball endmill. In the high-speed machining, the cutting force and surface roughness of workpiece show various characteristics in different cutting conditions. Especially, the surface roughness of the workpiece depends largely on pick feed and feed-per-revolution of the ball endmill. In the condition where pick feed and feed-per-revolution are equal, better surface roughness is measured. By obtaining good surface roughness at high speed, efficiency of machining can be increased.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.9
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• pp.57-62
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• 2021

CNC machining is used to fabricate various components. This has led to the development of processing-based industries for the production of automobile, appliances, semiconductors, and rockets. Additionally, this machining has enabled economical mass production of high-quality products in industries. Magnesium alloy with a hexagonal closed packed configuration is prone to difficulties during plastic machining, has a high oxygen affinity, and exhibits poor corrosion resistance to seawater and the atmosphere. In this research, Al alloy A5083 was used to investigate and analyze the surface roughness with a certain depth of cut fixed by the machining center (DVM-500II) and various feed rates, speeds, and processing methods after modeling and simulated machining with Gibbs CAM.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.3
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• pp.68-72
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• 2012

Al2017 is typical Duralumin of self-hardening aluminum alloy. It is lightweight, formability and machinability so throughout the industries have widely used automobile, electronics, semiconductor and aircraft as material. A variety of CNC machine tool processing technology, scientific principles and experience have been studied in order to increase accuracy and productivity. Using a machining center is to constant amount of side step and cutting characteristics studied changing depth of cut, revolution per minute and feed rate.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.10a
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• pp.219-224
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• 2004

There have been many researches on machine tool vibration and chatter to obtain assessment procedure and more productivity. In this paper chatter limit is predicted on a universal machining center which used a parallel mechanism. The prediction method uses the combination of structural dynamic characteristics and cutting dynamics. So the dynamic characieristics were obtained by vibration experiments. We showed the unstable cutting conditions, and from them we could plot the unstable borderlines.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.4
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• pp.556-562
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• 2012

Micro electrical discharge machining (${\mu}EDM$) has been used for non-conventional material removal. One drawback of ${\mu}EDM$ is low productivity. In this study, we tried to find the optimal machining conditions to manufacture the micro hole with an optimal machining time without loss of accuracy. Taguchi method was used to figure out the relation between machining parameters and characteristics of the process. It was found that the electrode wear, the entrance and exit clearance gave a significant effect on the diameter of the micro hole when the diameter of the electrode was identical. Grey relational analysis was used to determine the optimal machining condition for minimum machining time without loss of accuracy. The obtained optimal machining condition was the input voltage of 80V, the capacitance of 680pF, the resistance of $500{\Omega}$, the feed rate of $1.5{\mu}m$/s and the spindle speed of 2900rpm. The machining time was reduced to 48% without loss of accuracy under the optimal machining condition.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.7
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• pp.761-768
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• 2011

The large surface micro machining system includes the equipments and processes for manufacturing the ultra precision micro patterned products with large surface through the mechanical machining. Recent major issue on the micro machining technology may be the development of optical parts for the back light unit of display which has the largest market. This special issue makes up with three parts; the large surface micro machining system and machine, machining process and forming process. In this paper, the state-of-the-art and core technology of large surface micro machining system is introduced with focus on the manufacturing technology for the back light unit of LCD TV. Then, some research results on the development of a roll die lathe is introduced which involves the concept of machine design, improvement of thermal characteristics in the spindle system, improvement of relative parallelism and straightness between spindle system and long stroke feed table, machining of micro pitch patterns. Finally, the direct forming process is introduced as the future work in the large surface micro machining field.