• Journal of the Korean Society for Precision Engineering
• /
• v.14 no.3
• /
• pp.122-129
• /
• 1997

Machining technology has emerged to the point of performing atomic-scale fabrication. In tail paper atomic-scale machining characteristics are investigated by using Molecular Statics simulation method. The cutting model used in this work simulates machining with tools such as an AFM. It is shown that built-up edge formation and cutting forces depend on tool tip geometry. Also, the material flow during cutting is shown for various cutting conditions such as depth of cut, rake angle, and edge radius of tool.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2006.05a
• /
• pp.19-20
• /
• 2006

As the Mobile and Display technology are being developed quickly, new wireless devices are released in great numbers. They reduce existing devices' life time and demand a reduction of developing period of portable devices. With these demands, existing film cutting mold used many films of portable devices, especially LCD Display, needs to be more precise, and cheaper. In this research, we have analyzed machining characteristics of cutter shapes, materials, and cutting conditions for application to other films. Cutter edge was machined by slot cutting method and CAD program to select the cutter shape and cutter angle. Also, we have determined the optimal cutting conditions using high speed machining experiments to improve the productivity.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2001.10a
• /
• pp.344-348
• /
• 2001

In this study, experiments were carried out to investigate the characteristics of grinding and wear process of diamond wheel grinding ceramic materials. Normal component of grinding resistance was decreasing while increase of spindle speed. The resistance of vitrified bond wheel was less then that of resinoid bond wheel because of imbedded large holes on the surface of cutting edge. Surface roughness was decreasing while increase of spindle speed. The surface roughness after using vitrified bond wheel was less than that of resinoid bond wheel because of small elastic deformation. After continuous grinding of ceramics, cutting edge ratio of resinoid bond wheel decreases. For the case of vitrified bond wheel, cutting edge ratio does not change.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.13 no.1
• /
• pp.16-21
• /
• 2004

In order to investigate the characteristics of diamond wheel grinding of ceramic materials, grinding resistance, surface roughness of ground surface and image of grinding wheel were acquired using experimental method. Through the experiments, this makes it possible to observe grinding wheel behavior by grinding resistance, surface roughness and cutting edge ratio. In case of $Al_2O_3$, cutting edge ratio is bigger than that of $ZrO_2$ and $Si_3N_4$. That's because $Al_2O_3$ has a characteristic of low fracture toughness and bending stress.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2002.10a
• /
• pp.308-313
• /
• 2002

In order to investigate the characteristics of grinding and diamond wheel grinding ceramic materials, grinding resistance, surface roughness of worked surface and image of grinding wheel were acquired using experimental method. Through the experiments, this makes it possible to observe grinding wheel behavior by grinding resistance, surface roughness and cutting edge ratio. In case of A1$_2$O$_3$, cutting edge ratio is begger than that of ZrO$_2$and Si$_3$N$_4$. That's because A1$_2$O$_3$has a characteristics of low fracture toughness and bending stress.

• Journal of the Korean Society for Precision Engineering
• /
• v.31 no.3
• /
• pp.207-213
• /
• 2014

A study was carried out to fabricate the cutting tool geometry with micro/nanoscale on the single crystal diamond tool by using the FIB. The FIB technique is an ideal tool for TEM sample preparation that allows for the fabrication of electron-transparent foils. The FIB is appropriate techniques to sample and subsequently define the chemical composition and the structural state of mineral inclusion on the micro/nanoscale. The combination of FIB with a SEM allows for 3D information to be obtained from samples including 3D imaging. Cutting strategies were demonstrated to improve the performance of cutting tool geometry and to generate high aspect ratio micro cutting tool. A finely focused beam of 30keV Ga+ ions was used to mill cutting tool shapes for various micro patterns. Therefore FIB sputtering is used to shape a variety of cutting tools with dimensions in the $1-5{\mu}m$ range and cutting edge radii of curvature of under 50nm.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.19 no.1
• /
• pp.42-49
• /
• 2010

In general, the direct experimental approach to study machining processes is expensive and time consuming, especially when a wide range of parameters are included: tool, geometry, materials, cutting conditions, etc. The aim of this study is to verify the effectiveness of finite element method for orthogonal cutting process by comparing the simulated cutting forces with measured results. Two commercialized finite element codes $AdvantEdge^{TM}$ and Deform-$2D^{TM}$ have been used to simulate the cutting forces in orthogonal cutting process. In this paper, estimated cutting and feed force components are compared with experimental results for different two materials. As a result, it has been found that FEM simulation is effective for understanding and predicting the orthogonal cutting process although some improvements on friction model and remeshing process are needed.

• Educational Technology International
• /
• v.12 no.1
• /
• pp.95-124
• /
• 2011

Teachers' perception on educational attributes of new technologies can be dealt with a critical factor for enhancing educational effectiveness through using new technologies in education. The present study attempts to identify teachers' perceptions on educational attributes of cutting edge technologies established through a government-driven educational agenda, "The rural public school model", To achieve this purpose, e-survey was conducted for analyzing the differences of teachers' perceptions on educational attributes of TPCs, e-Whiteboards, and Fastel according to teachers' working areas, school levels, teaching experiences, and training experiences. Participants were 123 elementary school teachers (male:62, female:61) and 66 middle school teachers (male:37, female:29) who are working in the rural public model schools (Gyeonggi: 29, Chungcheong: 12, Jeolla: 30, Gyeongsang: 88, Gangwon: 22, Jeju: 8). The results are as follows: firstly, there were statistically significant differences according to regions, but no significant difference according to school levels; secondly, significant differences in teacher's perceptions on educational attributes of TPCs and Fastel according to teacher's teaching experiences were not shown; thirdly, differences in teachers' perceptions according to their training experiences were meaningfully significant in terms of three new technologies, Based on research results, the implications and further studies are suggested in order to increase educational effectiveness and efficiency for using the technologies.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2010.03a
• /
• pp.1438-1447
• /
• 2010

Construction sites are becoming larger and complex with the growth of national economy. Accordingly, It is essential to indentify real-time information about materials, equipments and manpower during construction at job sites. Even though research utilizing cutting-edge sensors has been conducted in architectural engineering field; this area of research is almost nil in civil engineering field. Therefore a feasibility study to find a way to apply cutting-edge sensors to an in-situ tunnel construction site adopting NATM is tried as the first step. After listing all construction materials needed in each activity, the most representative materials were identified so that IT technology can be applied by attaching and monitoring sensors to the selected materials; shotcrete and lining were selected as representative materials. Moreover, a plan to visualize construction process and progress management system using selected representative materials was proposed.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2002.10a
• /
• pp.203-208
• /
• 2002

This paper deals with turning experiments of aluminium alloy using a single crystal diamond with round cutting edge. A face cutting was conducted using a special precision machine to study the characteristic phenomena in heavy cutting of aluminium alloy. In many cases, one of the most important matter on the surface integrity is about a damaged layer remaining just under the surface after machining. A machined surface roughness can be improved at a small geometrical surface roughness under special cutting conditions, even if a steady vibration exists between a tool and a workpiece.