• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.04a
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• pp.161-166
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• 2003

The micro-extruding die is a die for manufacturing of fine-wire by extruding process. The fine-wire made from the micro-extruding can be effectively applied to fields of semiconductor parts and medical parts etc. It is predicted that the demand of fine-wire in industry is more and more increasing. In this study $\phi50\mu m$ micro-drill which is coated with diamond is used for drilling of super micro-hole sizes. For the machining of taper parts of entrance and exit, drill having $\phi50\mu\textrm{mm}$ inclination angle $20^{\circ}$and angle $30^{\circ}$ is used. This is useful for anti tool-breakage and excessive too-wear in drilling process. After micro-drilling, the polishing process by diamond abrasive and polishing wood s carried out for increasing surface roughness.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.1 s.256
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• pp.139-144
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• 2007

This paper presents development of carbon nanotube (CNT) tip modified by focused ion beam (FIB) and experimental results in non-contact mode of atomic force microscopy (AFM) using fabricated tip. We used an electric field which causes dielectrophoresis, to align and deposit CNTs on a conventional silicon tip. The morphology of the fabricated CNT tip was then modified into a desired shape using focused ion beam. We measured anodic aluminum oxide sample and trench structure to estimate the performance of FIB-modified tip and compared with those of conventional Si tip. We demonstrate that FIB modified tip in non contact mode had superior characteristics than conventional tip in the respects of wear, image resolution and sidewall measurement.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.04a
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• pp.167-172
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• 2003

The machining method by using end-milling tool has been applying in machining structures of various shapes because of the availability. Recently, all kinds of industries based on the parts of micro shape are developing, and the demands of mechanical micro machining technology are Increasing suddenly to produce these parts. According to such changes, the technology of the micro end-milling machining is applying as one of the most important machining means. This research is to aim at developing machining technology for various micro structures using micro end-mill. This paper introduces micro mechanical machining system with ultra precision, and demonstrates methods manufacturing all sorts of parts and moldings for industry and examples of applicable machining by using micro end-milling tool of micro sizes from hundreds to tens in diameter.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.1047-1050
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• 2000

As the progress of new industrial products or parts technology, the precise and fine machining technologies are needed more and more. Micro fabrication technology of these products are usally consisted of mechanical machining or MEMS technology. Direct machining by mechanical method is not applicable to mass production. MEMS technology also has several problems such as low mechanical strength, bad surface roughness and difficulty of 3 dimensional machining. In this study, we introduce several micro fabrication technology to make micro molds and dies and our project to develop these machining technology.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.759-762
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• 2000

In order to reduce lead-time and cost, recently the technology of Rapid Prototyping and Manufacturing (PR/M) has been used widely. So various RP/M methods have been developed and these systems commercialized several years ago. But we have carried out rapid product, such as sphere, by the milling process instead of RP system. in the case of sphere with three-dimensional shape. the machining method using conventional milling machine has resulted in some troubles because of its deformation and lack of stiffness which is due to usual work piece set up method. In this paper, the feasibility of milling process which is divided into two steps such as the-upper-and-1ower-face milling process using supporting material were investigated and suggested.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.2 no.2
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• pp.60-66
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• 2003

For the estimation of chatter lobe boundary it is very important to calculate the natural mode of cutting process. There are many time series algorithms for getting the natural mode of structural endmilling dynamics considering the cutting process. In this study, we have compared several time series methods such as AR algorithm, ARX, ARMAX, ARMA, Box Jenkins, Output Error, Recursive ARX, Recursive ARMAX considering the sampling frequency. As a results, the ARX, ARMAX and IV 4 are more desirable algorithms for the calculation of modal parameters such as natural frequency and damping ratio In endmilling operation. Also these algorithms may be adopted for the natural mode estimation of endmilling operation for chatter lobe prediction.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.11 no.3
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• pp.14-20
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• 2002

Recently, miniaturization and mass production are the main trends in manufacturing fields. Therefore, ultraprecision machining and MEMS technology have been taken more 7md more important position in machining of microparts. Micro endmilling is one of the prominent technology that has wide spectrum of application field ranging from duo parts to micro products, such as PDP md IT components, in precision products manufacturing. However, decreasing of burr is significant problem in making smooth and precise parts in micro endmilling. This paper shows removal characteristics of burr generated by micro endmilling process. This results satisfies micro endmilling for micro barrier ribs of heights is $50{\mu}m$, $100{\mu}m$, $200{\mu}m$, $300{\mu}m$, and observation from of burr. Additionally, it is necessary to understand the formation mechanism of burr of micro barrier ribs to iud proper decreasing method.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.11 no.3
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• pp.1-8
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• 2002

This study is continuous with the study I (A Study on the Modeling) and the sample impeller of this study is defined by the modeling process of the exclusive CAD/CAM system developed in the study Ⅰ. And, this study describes a method for the 5-axis machining of impeller blades formed by ruled surface. Therefore, the exclusive CAD/CAM system is the software for modeling md machining of impeller blades. By using the machining method suggested in this study, we could manufacture impeller blades on 5-axis CNC machining center and the machined impeller was very agreeable to the designed impeller. Thus, theories proposed in this study can be very useful for the 5-axis machining of impeller blades.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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• pp.435-440
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• 2000

In this study, we aims to develop the machining technology for the ultra precision surface and profile accuracy. For this purpose, we construct the electrolytic in process grinding system (ELID grinding) and apply to the cylindrical and internal grinding. Through the various machining experiments such as SCM steel., ceramics, tungsten carbide etc., we have obtained nanometer surface roughness. And we have applied this mirror grinding technique to hydraulic manual valve and mold core of mini disk optical pick-up base. For the development of fine mechanical part machining technology, e have made multi fiber optical connector using fine grinding technology. And constructed micro drilling system with process monitoring system which is possible to drill 50${\mu}{\textrm}{m}$ diameter hole.

• 연구논문집
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• s.25
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• pp.105-113
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• 1995

Fresnel lenses are developed for flat optics with the optical characteristics close to aspherical lens such as sharp focusing and dispersion instead of spherical or aspherical surface. Usually, these fresnel lenses and diffraction gratings are machined by high-energy beam such as electron beam machining, but recently with the development of ultra precision machine tool and machining technology, 3-dimension micro machining becomes preferable. This study on the micro machining of fresnel lens is carried out to develop the basic technology of ultra precision micro machining. The machined lens mold will be used for the manufacturing of fresnel lens with 120mm focal distance using synthetic resin material with 1.49 refractive index(PMMA), and the shape of lens is 48mm diameter, $300\mum$ pitch and about $5-700\mum$depth of groove in brass.