• Journal of the Korean Society for Precision Engineering
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• v.13 no.4
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• pp.136-142
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• 1996

Automatic monitoring of cutting process is one of the most important technology in machining. AE sensing technology has been applied to monitoring process and proved to be effective in detecting tool abnor- malities such as tool wear and fracture. In this experimental study. AE signals were detected from the tool holder for continuous and interrupted cutting, which obtained from changing workpice material configuration, under control of constant cutting speed from CNC lathe. From statistical and frequency analysis, the AE signals were analyzed to obtaining the characteristics of continuous and interrupted cutting conditions and tool failure. The Kurtosis values decreased but RMS voltages increased as the cutting speed increased, in both continuous and interrupted cutting. RMS voltage is suddenly increased but Kurtosis value is suddenly decreased when tool failure condition. Power spectrum density of AE signals when tool failure reaches extreme value around 0.065 cycles/ .mu. m.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1995.10a
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• pp.37-43
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• 1995

The cutting process of cage motor rotor require high precision and good roughness, the surface roughness fo cutting face is very important factor with effect on the magnetic flux density of cage motor rotor. The paper describes a cause of decrease in the cutting force and roughness on low temperature cooling tool by means of analysis on the mechanism of force system at cutting condition and experimental findings. The main results as compared with the room temperature cutting are as follow : 1) The cutting resistance decreased due to low temperature cooling tool. 2) The surface roughness decreased due to low temperature cooling tool. 3) The low temperature cooling tool effected machinability of the cutting direction in machined surface. 4) The low temperature cooling decreased burr of corner in feed direction.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.04b
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• pp.52-57
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• 1995

In order to suggest the proper cutting conditions of the CNC milling machining for the free-from surface, some experiments were carried out. In experiments, the influence of cutting conditions on the inclined spherical surface were examined by geometrical anlysis. In thos study, the roundness and cutting force were measured to know the effect of several cutting conditions on the machined surface and the cutting characteristics were carefully investigated. As the result, it was appeared that rigidder tool must be used and the cutting speed must be maintained constantlyfor more effective machining. It can be also known from the experiments that the improved machining surface obtained under about 80 degree, but coarse surface obtained over about 80 degree because of the existance of immproper shape of ball-end mill at the extreme portion.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.7 no.5
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• pp.127-133
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• 1998

This research intends to gain the sight for the qualitative characteristics of precision cutting by using the CNC lathe with a mono-crystal diamond(MCD) and a poly-crystal diamond(PCD) tool on the cutting distance. In case of an MCD tool, as the cutting distance increases, the surface roughness becomes worse and the standard deviation of surface roughness is small. In case of a PCD tool, as the cutting distance increases, the surface roughness becomes stable with a large standard deviation. The cutting force ratio(Ft/Fn) decreases as the nose radius increases and the decreasing ratio becomes larger for small nose radius.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.10
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• pp.62-70
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• 1996

We experimented on cutting characteristics-cutting force, behavior of cutting temperature, surface roughness. chip thickness under low temperature, which generated by liquid nitrogen(77K). The work-pieces were freezed to-195 .deg. C and liquid nitrogen was also sprinkled on cutting area in order to decrease an experimental error of machining in low temperature. The workpiece was became to -195 .deg. C in5 minutes. In cooled condition surface roughness of workpiece was better than normal condition. In addition, we investigated the possibility that surface roughness of workpiece and cutting force can be predicted analyzing cutting conditions by the trained neural network.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.341-346
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• 2004

Performance Evaluation of end mills for high speed cutting has been performed in a view of dynamic characteristics and noise-vibration under operation. The tools tested in this research consist of three foreign country made and one korean made. In addition, numerical models using finite element method are established, which are confirmed by experimental results. The evaluation results has been feedback for developing high performance end mills fur high speed cutting tools.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.04a
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• pp.478-483
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• 2003

Performance Evaluation of end mills for high speed cutting has been performed in a view of dynamic characteristics and noise-vibration under operation. The tools tested in this research consist of three foreign country made and one korean made. In addition, numerical models using finite element method are established, which are confirmed by experimental results. The evaluation results has been feedback fur developing high performance end mills for high speed cutting tools.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.4
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• pp.40-46
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• 2013

When impeller machining needs to be machined over a length in order to avoid interference with neighboring surfaces between material and tool, there are no databases about cutting condition according to tool slenderness ratio. So selection and machining of cutting condition depends on expert's experience. Therefore, the purpose of this paper is deciding cutting condition in roughing and finishing process of impeller according to slenderness ratio of AL7075's end-mill that is the most commonly used for impeller. We have tested for about relation between Slenderness ration and fluctuation width of the cutting force, surface roughness and depth of cut ratio to observe cutting characteristics according to slenderness ratio. The experiments of cutting characteristics and processing criteria are compared with AL5052 which is existing information.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.3
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• pp.66-74
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• 1997

In a high speed and high precision vertical machining center, chatter vibration is easily generated due to unbalanced masses in rotating parts and changtes of cutting forces. In this paper, modal test is performed to obtain modal parameters of the vertical machining center. In order to predit the cutting force of endmilling process for various cutting conditions, a mathematical model is given and this model is based on chip load, cutting geometry, and relationship between cutting forces and the chip load. Specific cutting constants of the model are obtained by averaging forces of cutting tests. The interactions between the dy- namic characteristics and cutting dynamics of the vertical machining center make the primary and the secondary feedback loops, and we make use of the equations of system to predict the chatter vibration. The chatter prediction is formulated as linear differential-differene equations, and simulated for several cases. Trends of vibration as radial and axial depths of cut are changed are shown and compared.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.7 no.3
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• pp.43-50
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• 1998

In the use of CNC machine tool, the unmanned production system has been growing in the manufacturing field. Thus, it is necessary to monitor adequate tool fracture during the cutting process efficiently. This experimental study is intended to investigate the development of flank wear in sysnchronous turning of differential materials(Aℓ/GC) which is used in industrial application and it is acknowledged as a machine to difficult material. In cutting process change of velocity, change of feed, and change of depth of cut were investigated on the effect of flank wear, and slenderness ratio is also investigated. The conclusions of this paper are summarized as follows; 1.Under the high cutting speed condition, the flank wear is affected by the feed and depth of cut. but the influence of feed on the flank wear is larger than the depth of cut and that is reduced when the velocity is low. 2.Under the high cutting speed, as the smaller slenderness ratio is, the shorter tool life is under the lower cutting speed, the effect of slenderness ratio on the flank wear is low. 3.Using the characteristics of cutting force, the flank wear of a tool can be detected 4. Investigating the development of flank wear, there are almost no differences between the characteristics of cutting force and feed force. Finally, these data from the differntial materials cutting process will be used in the basic field of precision and economic cutting process.