• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.04b
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• pp.137-141
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• 1993

In the case of a boring bar, the vibration amplitude is generallylarge due to its high slenderness. The boring bat is then modelled as a cantilever with dynamic force acting at the free end and a generalized model of nonlinear continous system is obtained. The Analysis of model is conducted for the specific case with a zero side cutting edge angle. The dynamic behaviour is investigated for machining processes in which the the overlap factor of regenerative effect is considered. The vibration characteristics of boring bar depth of cut rather than feed rate in given slenderness.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.837-841
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• 1996

It is the eccentricity that determines most of the characteristics of the elliptic gears. Accoding to the theoretical tooth profiles, two pairs of the elliptic gears were manufactured by using CNC wire cutting machine. For harmonious rotating motion, it is necessaryto consider operating pressure angle and module not to generate undercut. The characteristics of vibration were investigated by analyzer.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.439-440
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• 2009

• Proceedings of the Safety Management and Science Conference
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• 2002.05a
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• pp.221-225
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• 2002

Machinability improvement by the use of liquid nitrogen in cryogenic machining has been reported in various studies. This has been mostly attributed to the cooling effect of liquid nitrogen. However, No study has been found in discussion on whether liquid nitrogen possesses lubrication effect in cryogenic cutting. This paper presents lubrication mechanism related to chip microstructure. The friction reduction was further reflected In larger shear angle and less secondary deformation in the chip microstructures.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10a
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• pp.811-815
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• 1990

This paper describes the method on image acquisition and image processing in the turning process. The formation of discontinuous chips during high-speed oblique cutting without lubricant was observed by means of video camera recorder and stroboscope. The image processing technique for chip flow is described and the results are presented for variable feeds. It is concluded that experimental values of chip flow angle are similar to theoretical values of Stabler's rule.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.04a
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• pp.266-271
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• 1997

본 연구는 믹서기의 다지기칼날(Mincing Knife)이 구조적으로 가지고 있는 모멘트불평형(Couple Unbalance) 문제를 해결하기 위한 밸런싱방법을 제시한다. 유한요소법에 의하여 칼날에 작용하는 원심력, 정적 불평형량(Static Unbalance) 및 불평형각위치(Unbalance Angle)를 계산하고, 이를 바탕으로 반고리(Semiannular) 형상의 질량을 설계하여 모멘트 밸런싱을 수행하였다. 밸런싱을 수행한 후의 다지기칼날은 분해칼날(Cutting Knife)과 거의 비슷한 동적거동을 가지게 됨을 확인하였다.

• Journal of Oral Medicine and Pain
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• v.7 no.1
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• pp.41-46
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• 1982

The patient, 11 yeats old male was examined for routine oral health care. He had been hospitalized for treatment of nephritis. Hos physical condition os mental retarded & undergrowth state. In oral examination, notch on cutting edge and screw-driver shaped crown of maxillary central incisors, narrow crown and dwarfed & pinched occlusal surface of lower first molars and scars(rhagades) on the angle of the lip were shown. We diagnosed the above symptoms as dental defects of congenital syphilis; Huchinson's inscisors and mulberry molar.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.12
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• pp.1023-1029
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• 2015

Laser-assisted machining (LAM) is one of the most effective methods for enhancing the machinability of difficult-to-cut materials, such as titanium alloys and various ceramics, and has been studied by many researchers. LAM is a method that facilitates machining by softening a workpiece using a laser heat source. The advantages of the LAM process are decreases in tool wear, cutting force, and surface roughness. However, when the material is over-heated, melting or burning can occur. This study analyzed the heat source distribution with regard to overlapping of preheating on the laser heating path with an acute angle, a right angle and obtuse angles. Then, a power reduction method was proposed to reduce the melting and burning of the workpiece.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.6 s.183
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• pp.52-56
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• 2006

Punching tools like an electrodes are made by milling or etching or EDM. These methods had time consuming, low efficiency and air pollution. So, we have developed a shearing device which counter punching method for burrless cutting of micro wire. Using the straightened SUS304 wire with $200{\mu}m$ diameter, we confirmed the tendency of the shear plane for punch tools. It was impossible to completely remove the bun in the shearing process. In order to minimize the burr size and fine shear plane, we have accomplished the various experiment conditions such as the U-groove, the effect of the counter punch, shear angle and clearance. The results of the experiments show that indentation, slip plane and bent shape were related to the shear angle and clearance.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.4
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• pp.68-74
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• 2000

Even in a fully automated factory, many deburring operations are carried out manually . To remove or minimize the burreffectively or automatically, understanding of the burr formation which occur at the exit stage of machining is necessary. Burrs can be formed on the feed mark ridges an the edges of the machined parts in machining operations. These burrs are underirable in terms of the surface quality, the precise dimensioning of the machined parts and the safety of operators. This paper demonstrates the effectiveness of using end mill tool on minimizing the exit burr formation in machining . In particular, the experimental relationships between the size of exit burr and the cutting parameters are established in end mill machining . Methods to control the size of exit burr are then explained.