• Journal of the Korean Society for Precision Engineering
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• v.19 no.1
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• pp.186-195
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• 2002

The mechanism of micro machining of reacted layer on silicon surface were proposed. The depth of reacted layer and the change of mechanical property were measured and analyzed. Depth of hydrated layer which is created on the surface of silicon by potassium hydrate was analyzed with SEM and XPS. The decrease of the micro victors hardness of silicon surface was shown with the increase of the concentration of potassium hydrate and the change of the dynamic friction coefficient by chemical reacted layer was measured due to the readiness of machining. The experiment of groove machining was done with 3-axis machine with constant load. With chemical mechanical micro machining the surface crack and burrs generated by both brittle and ductile micro machining were diminished. And the surface profile and groove depth was shown in accordance with the machining speed and reaction time with SEM and AFM.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.99-104
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• 2004

Micro/meso cutting is getting more important in the fields of precision machining technology. A micro-turning lathe is one of parts to consist the Micro Factory. It accepts stepwise motion actuators that are used for feeding system instead of the conventional mechanism. It is consisted of two Piezoelectric ceramics; one is for feeding the slider, and the other is for clamping the slider in the guide way of the body. The linearity and positional accuracy of the actuators are good enough for high precision motion. The spindle unit is operated with DC motor on the top of the slider. The motion is communicated with miniaturized linear encoder attached on each side of axis. A mono crystal diamond tool is used for cutting tool. This micro-lathe has been made a machining experiment to see the characteristics of micro-machining.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.18 no.3
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• pp.294-299
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• 2009

Micro end-milling has been becoming an important machining process to manufacture a number of small products such as micro-devices, bio-chips, micro-patterns and so on. Many related researches have given grand effects to micro end-milling phenomenon, for example, micro end-milling mechanism, cutting force modeling and machinability. This paper strongly concerned actual problem, micro tool deflection, which causes excessive machining errors on the workpiece. Machining error were predicted and measured through a series of test micro cutting and analysis of their SEM images and FEM analysis. Experiments are carried out to validate the approaches.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.12 s.177
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• pp.42-50
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• 2005

This paper presents an ultra precision machining system using a high sensitive force sensing module to measure machining forces and penetration displacement in a tip-based nanopatterning. The force sensing module utilizes a leaf spring mechanism and a capacitive displacement sensor and it has been designed to provide a measuring range from 80 ${\mu}N$ to 8 N. This force sensing module is mounted on a PZT driven in-feed motion stage with 1 nm resolution. The sample can be moved by X-Y scanning motion stage with 5 nm resolution. In nano indentation experiments and patterning experiments, the machining forces were controlled and monitored by the force sensing module. Then, the patterned samples were measured by AFM. Experimental results demonstrated that the developed system can be used as an effective device in nano indentation and nanopatterning operation.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.97-100
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• 2004

In recent years, a demand for micro-structure machining is increasing by the development of information and optics industries. Micro machining technology is in general well known in the field of lithograghy. However, the requirement of producing micro machine and/or micro mechanism with metal materials will be increased since a variety of workpiece configurations can be easily made. In this paper, ultra precision machine is developed to obtain micro groove and mirror surface using single crystal diamond tool. According to the cutting experiment, no burr was found at the edge of V-grooves, and the surface roughness of copper is about 1～3nm Ra. It is verified that ultra precision machine is effective to high precision machining.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.8
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• pp.126-133
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• 2002

The cutting thickness of ultra-precision machining is generally very small, only a few micrometer or even down to the order of a few nanometer. In such case, a basic understanding of the mechanism on the micro-machining process is is necessary to produce a high quality surface. When machining at very small depths of cut, metal flow near a rounded tool edge become important. In this paper a finite element analysis is presented to calculate the stagnation point on the tool edge or critical depth of cut below which no cutting occurs. From the simulation, the effects of the cutting speed on the critical depths of cut were calculated and discussed. Also the transition of the stagnation point according to the increase of the depths of cut was observed.

• Journal of Mechanical Science and Technology
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• v.17 no.5
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• pp.691-697
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• 2003

Extensive researches have been carried out on machine tool chatter to obtain assessment procedure and improvement measures. In this study, chatter limit is predicted on a newly fabricated universal machining center by the combination of structural dynamic characteristics and cutting mechanics. We showed the unstable cutting conditions, and from them we could plot the unstable borderlines. From the chatter simulations we could say that the newly built universal machining center can be well used in the finishing machining of steel as other common machine tools.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.10
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• pp.208-213
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• 2001

High speed milling(HSM) is one of the emerging cutting process having tremendous potential not only in increased metal removal rates but also in improved surface finish, burr free edge, dimensional accuracy and a virtually stress free component after machining. The High efficiency and accuracy in machining of die/mold materials can be obtained in high speed machining, so it is necessary to analytic the mechanism of high speed cutting process : cutting force, acoustic emission signal.

• International Journal of Precision Engineering and Manufacturing
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• v.4 no.3
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• pp.62-67
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• 2003

The grinding force generated during the grinding process causes an elastic deformation of the workpiece, grinding wheel, and machine system. Thus, the true depth of cut is always smaller than the apparent depth of cut. This is known as machining elasticity phenomenon. The machining elasticity parameter is defined as a ratio between the true depth of cut and the apparent depth of cut. It is an important factor to understand the material removal mechanism of the grinding process. To increase productivity, the value of this machining elasticity parameter must be large. Therefore, it is essential to know the characteristics of this parameter. The objective of this research is to study the effect of the major grinding conditions, such as table speed, depth of cut, on this parameter experimentally, Through this research, it is found that this parameter value is increasing when the table speed is decreasing or the depth of cut is increasing. Also, this parameter value depends on the grinding mode (up grinding, down grinding).

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.2
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• pp.71-76
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• 2008

Micro end-milling is one of effective technology that is able to do ultra-precision machining while increasing the productivity and has wide application field. But selection of machining condition is very difficult because of complicated machining mechanism. Therefore this study was carried out to select working factors to get the optimum surface roughness. Machining condition are depth of cut, feed rate and spindle revolution. The result of this study showed that Surface roughness was affected, in the other of depth of cut, spindle revolution, feed rate. And this study provided an regression equation relating surface roughness to working factors through Regression Analysis and determination coefficient of regression equation had a satisfactory reliability of 79%.