• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1997.10a
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• pp.88-93
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• 1997

Ball-end milling process is widely used in the die and mold manufacturing because of suitable for the machining of free-form surface. Pencil cutting can eliminate overload in uncut area caused by large diameter of ball-end mill before finish cutting. As the ball-end mill for pencil cutting is long and thin, it is easily deflected by cutting force. The tool deflection when pencil cutting is one of the main reason of the machining errors on a free-from surface. The purpose of the research is to find out the characteristics of deflected cutter trajectory by eddy-current sensor.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.157-160
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• 1995

Pencil cutting can eliminate overload in uncut area caused by large diameter ball-end mill before finish cutting. As ball-end mill for pencil cutting is long and type, it is easily deflected by cutting force. The tool deflection when pencil cutting with thin and long ball-end mill is one of the main reason of the machining errors on a free-form surface. The purpose of the research is to find the characteristics of deflected cutter trajectory by eddy-current sensor.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.5
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• pp.191-197
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• 2007

Inclined surface milling in the mould and die industries is one of the most commonly needed cutting process. For the variety and complexity of cutting characteristics in various cutting condition, it is difficult to select a optimal tool path orientation. Especially, when the cutting process becomes unstable, it induces self-exited vibrations, a frequent cause of poor tool life, rough surface finish, damage to the workpiece and the machine tool itself, and excessive down time. The comparative results through FFT analysis in this study provide a guideline for the selection tool path orientation.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.934-938
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• 2000

Built-up edge affects the surface integrity of the machined surface and tool wear. Tool geometry and cutting conditions are very important factors to remove BUE. In this paper, we optimized the geometry of the metal slitting saw .1nd cutting conditions to remove BUE by the experiment. In general, the metal slitting saw is plain milling cutter with thickness less of a 3/16 inch. This is used for cutting workpiece where high dimensional accuracy and surface finish are necessary. The experiment was planned with Taguchi method that is based on the orthogonal array of design factors(coating, rake angle, number of tooth, cutting speed, feed rate). Response table was made by the value of the surface roughness, the optimized tool geometry and cutting conditions through response table could be determined. In addition. the relative effect of factors were identified by the variance analysis. filially. coating and cutting speed turned out important factors.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.9
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• pp.55-62
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• 2003

This paper investigates the micro-cutting of cemented carbides using PCD (polycrystalline diamond) and PCBN (polycrystalline cubic boron nitride) cutting tools are performed with SEM direct observation method. The purpose of this study is to make clear the cutting mechanism of cemented carbides and the fracture of WC particles at the plastic deformation zone in orthogonal micro-cutting. And also to achieve systematic understanding, the effect of machining parameter on chip formation and machined surface was studied, including cutting speed, depth of cut and various tool rake angle. Summary of the results are shown below. (1) Three type of chip formation process have been proposed by the results of the direct observation in orthogonal micro-cutting of cemented carbide materials. (2) From the whole observation of chip formation, primary WC particles are crushed and/or fine grained in the shearing deformation zone. A part of them are observed to collide directly with a cutting edge of tool by following the micro-cutting. (3) Surface finish, surface morphology and surface integrity is good to obtain by cutting with PCD cutting tool compared with PCBN. (4) The machined surface has the best quality near the low cutting speed of 10${\mu}m$/sec with a cutting depth of 10 ${\mu}m$ using 0$^\circ$ rake angle and 3$^\circ$ flank angle in this condition, but it was found that excessively low speed, for example the extent of 1 ${\mu}m$/sec, is not good enough to select for various reason.

• International Journal of CAD/CAM
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• v.7 no.1
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• pp.51-60
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• 2007

This paper presents an algorithm of optimal cutting tool selection for machining of the point-based surface that is defined by a set of surface points rather than parametric polynomial surface equations. As the ball-end and fillet-end mills are generally used for finish machining in a 3-axis computer numerical control machine, the algorithm is applicable for both cutters. The optimum tool would be as large as possible in terms of the cutter radius and/or corner radius which maximise (s) the material removal rate (i.e., minimise (s) the machining time), while still being able to machine the entire point-based surface without gouging any surface point. The gouging are two types: local and global. In this paper, the distance between the cutter bottom and surface points is used to check the local gouging whereas the shortest distance between the surface points and cutter axis is effectively used to check the global gouging. The selection procedure begins with a cutter from the tool library, which has the largest cutter radius and/or corner radius, and then adequacy of the point-density is checked to limit the accuracy of the cutter selection for the point-based surface within tolerance prior to the gouge checking. When the entire surface is gouge-free with a chosen cutting tool then the tool becomes the optimum cutting tool for a list of cutters available in the tool library. The effectiveness of the algorithm is demonstrated considering two examples.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.3
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• pp.713-723
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• 1995

In intelligent machine tools, a computer based control system, which can adapt the machining parameters in an optimal fashion based on sensor measurements of the machining process, should be incorporated. In this paper, the technology for adaptively optimizing the cutting conditions to maximize the material removal rate in face milling operations is proposed using the exterior penalty function method combined with multilayered neural networks. Two neural networks are introduced ; one for estimating tool were length, the other for mapping input and output relations from experimental data. Then, the optimization of cutting conditions is adaptively implemented using tool were information and predicted process output. The results are demonstrated with respect to each level of machining such as rough, fine and finish cutting.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1996.10a
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• pp.64-74
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• 1996

The meachanism for cutting epoxy resins specimens which were specially provided was experimentally investigated to obtain a fine surface finish. the specimens were cut the three-dimensional undrer dry conditions using a lathe. the relationship between the topography of the cut surface due to the change rate of temperature of the cutting condition using sintered carbides (P20, K10, KT150) was investigated. the main results obtained are as follows: 1) The change rate of temperature of the cutting edge is increased in nearly proportion ot cutting speed feed rate depth of cut. 2)The profile of surface roughness were regulated k10 but irregulated P20 KT150. 3) The surface roughness value decreased K10 rather than P20 KT150. 3) The surface roughness value decreased K10 rather than P20 KT 150.4)The cutting resistance increased thrust force rather than cutting force due to the visco-elastic material of epoxy resins.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.73-78
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• 1994

Wear and fracture mode of ceramic tool for hardened SKD11 steel was investigated by face milling in this study. The cutting force and Acoustic Emission(AE) signal were utilized to detect the wear and fracture of ceramic tool. The following conclusions were obtained : (1) The wear and fracture modes of ceramic tool are characterized by three types: \circled1wear which has normal wear and notch wear, \circled2 wear caused by scooping on the rake face, \circled3 large fracture caused by thermal crack in the rake face. (2) The wear behaviour of ceramic tool can be detected by the increase of mean cutting force and the variation of the AE RMS voltage. (3) The catastrophic fracture of ceramic tool can be detected by the cutting force(Fz-component). (4) As the hardness of work material increased, Acoustic Emission RMS value and mean cutting force(Fz) increased linearly, but the tool life decreased.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.6
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• pp.16-21
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• 2011

In machining operation, the quality of surface finish is an important factor for many turned products. In this paper, surface quality in turning machining considering angle variation has been investigated. To reach this goal, surface quality turning experiments are carried out according to cutting conditions with angle variation. The variable cutting conditions are cutting speed, feed rate and taper angle of workpiece. The surface roughness was measured and the effects of cutting conditions were analyzed by the method of analysis of variance (ANOVA). From the experimental results and ANOVA, it is found that a better surface roughness can be obtained as decreasing feed rate, increasing cutting speed. Taper angle variation has been more influenced by feed rate and cutting speed.