• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 추계학술대회 논문요약집
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• pp.128-128
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• 2003

• 한국공작기계학회논문집
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• 제16권3호
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• pp.37-43
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• 2007

Recent technological developments in machine tools have been focused on high speed, low vibration machining and high precision machining. And the concern with multi-functional machining has been increased for the last several years. Multi-tasking machines are widely used in machine tool industries. Laser multi-tasking machine has been developed for high precision and fewer vibration machining. The purpose of this study is to evaluate the effects of structural reinforcement on Laser multi-tasking machine which is comprehensively combined turning center and laser machine. Up to date, for the structural stability evaluation of a multi-tasking machine, the analysis model has been considered only the weight of the upper parts. The positions of upper parts on multi-tasking machine have not been considered in the model. So, the results of the present FE model have revealed some difference with measurement data in case of multi-tasking machine. Design of the machine and structural analysis is carried out by FEM simulation using the commercial software CATIA V5. In the result of the structural analysis, effectiveness of reinforcement of the bed was confirmed.

• 한국정밀공학회지
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• 제15권11호
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• pp.58-66
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• 1998

A low power consuming laser scanning vibrometer is studied for its development. For its optical system, a laser interferometer is constructed to use the Doppler effect. In order to reduce the driving power of the scanning system, a small displacement of the scanning system is produced, which is achieved by using a magnetostrictive actuator. A sufficient rotating angle of the scanning system is obtained by using an amplified displacement from the resonant phenomena of a second order mechanical system composed of a mass and spring. The control of the magnetostrictive actuator using a Terfenol-D is performed without using a feedback system to help reduce the power consumption. The vibration analysis is made for the sinusoidal scanning input to have the space domain information from the time domain of the velocity of a vibration object. As a partial work of development of a tow power consuming laser scanning vibrometer, in this work, a scanning system which has the above features is developed and experimentally investigated. For the purpose of the optical system calibration, the vibration measurement for one axis is presented and the future works are discussed.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2009년도 추계학술대회 논문집
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• pp.433-434
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• 2009

• 한국정밀공학회지
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• 제16권9호
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• pp.62-67
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• 1999

In milling, cutting tool ins directly attached to spindle and this tells that spindle can provide very useful information on the cutting tool condition such as wear or breakage. Since spindle is rotating at a high speed, measuring spindle velocity using a noncontacting measurement system gives the best information which can be obtained. Due to the force applied to spindle through cutting tool, velocity of spindle changes. And any change in cutting tool condition affects cutting force and consequently spindle vibration. With the intent of continuously monitoring cutting tool condition in intermittent machining operations in a benign manner, a noncontacting velocity measurement system using a laser Doppler velocimeter was assembled to measure spindle torsional vibration. Spindle vibration was measured and analysis of it in the frequency domain yielded a measure which corresponded to amount of cutting tool wear in milling.

• 한국안광학회지
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• 제6권2호
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• pp.77-80
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• 2001

본 논문은 저출력 He-Ne 레이저의 스펙클 현상을 이용하여, 진동하는 물체의 표면요소들에 의한 운동상태를 분석하는데 그 목격이 있다. 레이저에서 나온 빛은 구리판에서 반사되어 진동판에 스펙클로 나타난다. 이것을 뒤에 설치된 스피커의 음파로 진동시키면 스펙클은 여러 가지 형태로 변화한다. 진동판이 최대로 진동할 때의 진동수는 역학적 공명 진동수이므로 그때의 스펙클변화를 진동판에 표시한다. 스펙클은 진동하는 부분과 진동하지 않는 부분으로 나뉘어 지는데 진동하는 부분은 흐려지거나 스펙클이 나타나지 않는다. 진동모드의 변화는 진동판의 종류와 크기, 고정단 집게의 위치에 따라 달라지는 것을 볼 수 있다.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 춘계학술대회 논문집
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• pp.281-286
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• 2004

The vacuum cleaner motor runs on very high speed for the suction power. Specially, the motive power is provided by the impeller being rotate on very high speed. And centrifugal fan consists of the impeller, the diffuser, and the circular casing. Due to the high rotating speed or the impeller and small gap distance between the impeller and diffuser, the centrifugal fan makes very high noise level at BPF and harmonic frequencies. In order to calculate the sound pressure of centrifugal fan, the unsteady flow data is needed. And Noise cause is dividing to fluid noise by exhaust flow of fan and vibration noise by rotational vibration of vacuum cleaner fan motor. Until now, measuring method has been used to measure vibration by the accelerometer; this method has been not measured for the vibration in some parts of brush and commutator because of motor construction and 3-D vibrating mode. This paper was purposed on the accurate analysis, using laser vibration analyzer,. By using this measured data of noise cause against the difficult part in old times, we would like to use for the design of silent fan motor.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 추계학술대회 논문집
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• pp.245-249
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• 2004

This paper describes the vibration characteristics of Nd:YAG laser welding plates analyzed time-average Electronic Speckle Pattern Interferometry(ESPI). In laser welding, the travel speed has influence on a mechanical properties, such as elastic modules, response frequencies and so on, which is resulted on a residual stress of the welding zone. the response frequencies related to elastic modules are determined by time-average ESPI and the results, as compared to each condition, are used to estimate optimal condition of travel speed.

• 대한기계학회논문집
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• 제18권8호
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• pp.2123-2138
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• 1994

A study on the dynamic mechanical properties of the high strength carbon fiber epoxy composite beam was carried out. The macromechanical model was used for the theoretical analysis of the symmetric laminated composite beam. The anisotropic plate theory and Bernoulli-Euler beam theory were used to predict the effective flexural elastic modulus and the specific damping capacity of laminated composite beam. The free flexural vibration and torsional vibration tests were carried out to determine the specific damping capacities of the unidirectional laminated composite beam. The vibration tests were performed in a vacuum chamber with laser vibrometer system and electromagnetic hammer to obtain accurate experimental data. From the computational and experimental results, it was found that the theoretical values with the macromechanical analysis and the experimental data of symmetric laminated composite beam were in good agreement.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2009년도 추계학술대회 논문집
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• pp.370-375
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• 2009

The purpose of this study is to reduce the vibration of the computer by developing the vibration absorber and damper. The eccentricity of the cooling fan causes the vibration of the computer. We designed the material properties of the vibration absorber by FEM model within operation frequencies of the cooling fan. We experiment the overall analysis and system analysis. The vibration of cooling fan is measured by using a laser vibrometer. The result shows that the proposed vibration absorber and damper reduce the vibration of the computer.