• 한국생산제조학회지
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• 제9권1호
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• pp.81-87
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• 2000

A variable cutting speed control model was developed to be implemented for the flexible disk grinding process Control algorithm was based on the error referred by the discrepancy between current disk angle and intended one that are pro-posed to produce desired resulting depth of cut. Controller was implemented in two different aspect One was to initiate the control law from the beginning while the other was to activate as soon as the disk start to produce ground surface i.e. The beginning of the between edges stage. Several performance analysis were conducted comparing various process parameters such as cutting force disk angle depth of cut and disk speed with respect to process transition time Tentative results revealed that controller implemented from the earlier stages of the process showed better performance than the other revealed that controller implemented from the earlier stages of the process showed better performance that the other.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.891-894
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• 2001

In this work, an effort is made to investigate the behavior of a chip, from its initial flow to its final breaking stage. The expression for chip flow in grooved tools is verified analytically using FEM. Cutting parameters like velocity and depth of cut have a profound influence on chip flow behavior. Chip curling increases and, for a given tool geometry, effectiveness of the groove increases with increasing depth of cut. The feasibility of tool design using FEM simulations is also demonstrated. Optimization of tool geometry results in better chip control.

• 한국정밀공학회지
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• 제7권4호
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• pp.65-72
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• 1990

After observing grinding characteristics according to variable grinding condition in order to raise the grinding effect without making worse the grinding quality by using general grinding machine, main conclusions of this study are as follows; 1) When grinding quality is constant, grinding effect is changed according to the speed of the workpiece. But the rapidly increasing critical speed of table is($V_w{\leq}4m/min$). 2) As grinding effect is equal, the lower the speed of the workpiece becomes, the lower the grinding force and surface roughness obtains good results. 3) In terms of grinding method, the down cut grinding method produces good grinding surface royghness in case of little grinding depth;otherwise, the up cut method in case of more grinding depth.

• 한국정밀공학회지
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• 제17권5호
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• pp.131-136
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• 2000

This paper is concerned with the surface roughness and the bending strength of ground workpiece in ZrO2 ceramic grinding. Surface roughness was measured with surface tracer and bending strength value was obtained by three-point bending test on machining center using tool dynamometer. Grinding experiments were carried out to examine the effects of grinding conditions including diamond mesh size, table speed, and depth of cut on ground surface roughness. The correlation between surface roughness and bending strength was also inspected. The experimental results indicate that the rougher surface is produced as the mesh size of diamond wheel is reduced and table speed is increased, but surface roughness is not affected by depth of cut. The values of bending strength decrease as the values of Ra, Rmax and Ku increase.

• Geomechanics and Engineering
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• 제20권5호
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• pp.421-432
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• 2020

Cutting of rocks is very common encountered in tunneling and mining during underground excavations. A deep understanding of rock-tool interaction can promote industrial applications significantly. In this paper, a distinct element method based approach, PFC^3D, is adopted to simulate the rock cutting under different operation conditions (cutting velocity, depth of cut and rake angle) and with various tool geometries (tip angle, tip wear and tip shape). Simulation results showed that the cutting force and accumulated number of cracks increase with increasing cutting velocity, cut depth, tip angle and pick abrasion. The number of cracks and cutting force decrease with increasing negative rake angle and increase with increasing positive rake angle. The numerical approach can offer a better insight into the rock-tool interaction during the rock cutting process. The proposed numerical method can be used to assess the rock cuttability, to estimate the cutting performance, and to design the cutter head.

• 한국정밀공학회지
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• 제18권11호
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• pp.101-106
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• 2001

In this work, an effort is made to investigate the behavior of a chip, from its initial flow to its final breaking stage. The expression for chip flow in grooved tools is verified analytically using FEM. Cutting parameters like velocity and depth of cut have a profound influence on chip flow behavior. Chip curling increases and, for a given tool geometry, effectiveness of the groove increases with increasing depth of cut. The feasibility of tool design using FEM simulations is also demonstrated. Optimization of tool geometry results in better chip control.

• 한국공작기계학회논문집
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• 제13권2호
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• pp.9-16
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• 2004

Because a generated heat during grinding operation makes a serious deformation on a ground surface as a convex form, a real depth of cut in deformed zone has larger than an ideal depth of cut. Consequently, the ground surface has a geometric error as a concave form after cooling the workpiece. In this study, the force and the geometric error of surface grinding were examined. From evaluating magnitude and mode of the geometric error according to grinding conditions, an optimal grinding condition was proposed to minimize the geometric error. In addiction the relationship between the geometric error and the grinding force was found out. Due to least square regression it was able to predict the geometric error by using the grinding force.

• 반도체디스플레이기술학회지
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• 제16권2호
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• pp.70-74
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• 2017

Given two stereo images of a scene, it is possible to recover a 3D understanding of the scene. This is the primary way that the human visual system estimates depth. This process is useful in applications like robotics, where depth sensors may be expensive but a pair of cameras is relatively cheap. In this work, we combined our interests to implement a graph cut algorithm for stereo correspondence, and performed evaluation against a baseline algorithm using normalized cross correlation across a variety of metrics. Experimental trials revealed that the proposed descriptor exhibited a significant improvement, compared to the other existing methods.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2001년도 춘계학술대회 논문집(한국공작기계학회)
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• pp.188-191
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• 2001

Generally, main factors of tool damage are cutting speed, feed rate and depth of cut. The increase of those factors can cause tool breakage or worsen product quality such as machining accuracy deterioration. Those three factors are concerned with cutting force. Cutting force reaches at its maximum value when cutter blade cuts away the object directly, and it is the time when tool damages are at high probability. In this study, we detect the maximum cutting force affecting tool damage and control the maximum cutting force based on the measured peak force.

• Composites Research
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• 제13권5호
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• pp.44-49
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• 2000

Although the net-shape molding of composites is generally recommended, molded composites frequently requires cutting or grinding due to the dimensional inaccuracy for precision machine elements. The surface roughness and cutting force were also measured to investigate the surface grinding characteristics of the composites using the vitrified bonded wheel (WA, GC). The experiments were performed dry grinding conditions with respect to cutting speed, feed speed, depth of cut of the stacking sequence $[O]_{nT.}$ From the experimental investigation, the optimal conditions both the vitrified bonded wheel WA and GC for the surface grinding are suggested.