• Journal of the Korean Society for Precision Engineering
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• v.14 no.3
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• pp.122-129
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• 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
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• 1993.04b
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• pp.102-107
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• 1993

The achievable machining accuracy depends upon the level of the micro-engineering, and the dimensional tolerances in the order of 10nm and surface roughness in the order of 1nm are the accuracytargets to be achieved today. Suchrequirements cannot be satisfiedby the conventional machining processes. Single point diamond turning is one of the new techniques which can produce the parts with such accuracy limits. The aims of this thesis are to get a better understanding of the complex cutting process with a diamond tool and, consequently, to develope a predicting modelof a turned surface profile. In order to predict the turned surface profile, a numerical model has been developed. By means of this model, the influences of the cutting conditions, the material properties of the workpiece, the geometry of the cutting tool and the dynamic behaviour of the lathe and their influences via the cutting forces upon the surface roughness have been estimated.

• Structural Engineering and Mechanics
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• v.34 no.3
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• pp.301-317
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• 2010

This paper studies the reliability of an analytical tool for predicting the lateral load-deformation response of RC columns while subjected to lateral cyclic displacements and axial load. The analytical tool in this study is based on a fiber element model implemented into the program DRAIN-2DX (fiber element). The response of RC column under cyclic displacement is defined by the behavior of concrete, and reinforcing steel under general reversed-cyclic loading. A tri-linear stress-strain relationship for the cyclic behavior of steel is proposed and the improvement in the analytical results is studied. This study only considers the behavior of columns with flexural dominant mode of failure. It is concluded that with the implementation of appropriate constitutive material models, the described analytical tools can predict the response of the columns with reasonable accuracy when compared to experimental data.

• Transactions of Materials Processing
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• v.21 no.2
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• pp.119-125
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• 2012

The present study addresses a direct patterning process on a plastic film using ultrasonic vibration energy. In this process, a tool horn containing micro-patterns is attached to an ultrasonic power supply, and is used with ultrasonic vibration to replicate micro-patterns on the surface of a plastic film. To improve the replication characteristics of the micro-patterns, the effect of the die shape of the ultrasonic patterning process was investigated with respect to the flow direction control. Finite element analyses were performed to predict the flow characteristics of the polymer with variations in die design parameters. Experiments were conducted using the optimally-designed die, from which it was possible to attain much improved pattern replication.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.7
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• pp.1446-1452
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• 2002

In the turning process, the feed is usually selected by a machining operator considering workpiece, cutting tool and depth of cut. Even if this selection can avoid power saturation or tool breakage, it is usually conservative compared to the capacity of the machine tools and can reduce the productivity significantly. This paper proposes a selection method of the feed and the reference cutting force based on MRR(material removal rate), maximum spindle power and specific energy. In order to estimate and control cutting force accurately in transient and steady state, this study utilizes a synthesized cutting force estimation method and a Fuzzy controller. The experimental results show that these systems can be useful for the unmanned turning process.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.4 no.4
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• pp.21-27
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• 2005

Recently researches for high speed machining have been actively performed. Few analytical studies, however, have been published. In this paper, a model of cutting forces is analytically studied to predict cutting characteristics in end mill process, especially considering both feed rate and spindle speed. The developed cutting model is based on Oxley's machining theory, which predicts the cutting forces from input data of workpiece material properties, tool geometry and cutting conditions. Experimental verification has been performed to verify the predictive cutting force model using tool dynamometer. It has been found that the simulation results substantially agree with experimental results.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.5
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• pp.76-81
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• 2012

The continuing demand for increasingly slimmer and brighter liquid crystal display(LCD) panels has led to an increased focus on the role of the light guide panels(LGPs) or optical films that are used to obtain diffuse, uniform light from the backlight unit(BLU). And the most basic process in the production of such BLU components is the micromachining. LCD BLUs comprise various optical elements such as a LGP, diffuser sheet, prism sheet, and protector sheet with micro patterns. High aspect ratio patterns are required to reduce the number of sheets and enhance light efficiency, but there is a limit to the aspect ratio achievable for a given material and cutting tool. Therefore, this study comprised a series of experimental evaluations conducted to determine the machining feasibility in microcutting various aspect ratio patterns on electroless nickel plated die materials when using single-crystal diamond tools. Cutting performance was evaluated at various cutting speeds and depths of cut using different machining methods and machine tools.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.6 no.4
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• pp.36-43
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• 2007

Dieless CNC forming is an innovative technology which can form various materials with complex shape by numerically controlled incremental forming process. In order to apply the technology to industrial parts, however, many problems such as spring-back, rising of material, and trimming difficulty must be solved. In this paper a new dieless CNC forming method to improve forming quality is proposed, which consists of how to modify its original shape in CAD and how to generate its CNC tool path in CAM. The effectiveness of the proposed procedures is tested with a brake dust shield of a vehicle. The results shows that the method proposed enhances the forming quality up to 48% compared to traditional method.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.818-822
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• 2000

The low density, sustained high temperature strength and excellent resistivity to acid materials have made them strong candidate materials for future aerospace or medical applications. Nowadays their usage has already been broaden to everyday's commercial applications such as golf club heads, finger rings and many decorative items, Anticipating the general use of this material and development of the titanium alloys in domestic furnaces, the review and the study of the machining parameters for those alloys are deemed necessary. The present studies are concentrated to the machining parameters of the Ti-6Al-4V alloys due to their dominant position in the production of titanium alloys.

• Journal of Mechanical Science and Technology
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• v.16 no.5
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• pp.633-638
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• 2002

An approach to enhance dimensional accuracy of the grinding process has been presented, and grinding of a glass material with a metal-bonded diamond wheel has been studied. In this study, a grinding tool is suspended flexibly and controlled by an electromagnetic actuator. During grinding, profile error of a ground surface is indirectly measured and fed back to a control system. A model of grinding error has been suggested on which the indirect measurement has been based. An optimal PID control is adopted and effectiveness of the in-process feedback control has been verified experimentally.