• Journal of Advanced Marine Engineering and Technology
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• 제30권5호
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• pp.629-635
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• 2006

Manufacture of motor by laser has been studying realization that was demands on market for lightening and miniaturization. Moreover. early in the 1980s. manufacture of parts for automobiles by laser welding was already successfully introduced. The purpose of this study was to develop production technology of the high quality laminated stator core for motor by pulsed Nd:YAG laser heat source. In the event of adjusting defocus and voltage to control humping in laser welding of the laminated core. sound bead could be obtained. but deep penetration was not. Therefore. explosive evaporating plasma was controlled by adjustment of peak power on pulse width. Particularly, because explosive evaporating plasma induced high peak power, made molten metal in keyhole scatter. a suitable adjustment of peak power was required to obtain sound bead. As a results of experiment. sound bead and deep penetration could be obtained.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2007년도 추계학술대회 논문집
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• pp.211-212
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• 2007

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 제14회 신호처리 합동 학술대회 논문집
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• pp.777-783
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• 2001

This paper is mainly concerned with the state of the practical developments of a constants PWM bridge type resonants DC-DC suitable converter for Nd:YAG Laser with a Microprocessor. (PIC16C54 & 8051) The use of IGBT power supply with feedback control of flashLamp currents imparts a advantages to Nd:YAG Laser for materials processing. these include the alility to tailor the pulseshape and modify pulse parameters on a pulse- by pulse basis. And Correct choice of pulseshape can enhance the repeatability of the process. as higher power IGBT became available, act ive pulseforming power supplies will find greater user in deep hole drilling machine By Using certain control tecniques, utililized in designing Pic16c54 from Microchip technology and Intel 8051, also Mornitoring from Microsoft Visual Basic 5, And it allowed us to designed and fabricate ahigh repel it ion rate and high power(HRHP) pulsed Nd:YAG laser system, As a result of that, the current pulsewidth could be contort led 200s to 350s(step 50s) , and the pulse repetition rate could be adjusted 500pps to 1150pps. In addition, in the case of one laser head consisting of a Nd:YAG laser rod and two flashlamps , the maximum laser output of 240w was produced at the condition of 350s and 1150pps, and that of about 480w was generated at the same condition when two laser heads were arranged in cascade.

• 한국레이저가공학회지
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• 제8권1호
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• pp.27-37
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• 2005

During laser spot welding of the braun tube electron gun, phenomena such as serious spattering and oxidative reaction, etc. were occurred. The spatter occurred from weld pool affects the braun tube, namely it blocks up a very small hole on the shadow mask and causes short circuit between two poles of the electron gun. We guessed that high power density and oxidative reaction are main sources of these problems. So, we studied to prevent and to reduce spatter occurring in spot welding of the braun tube electron gun using pulsed Nd:YAG laser. The characteristics of laser output power was estimated, and the loss of laser energy by optical parameter and spatter was measured by powermeter. The effects of welding parameters, laser defocused distance and incident angle, were investigated on the shape and penetration depth of the laser welded bead in flare and flange joints. From these results, the laser peak power was a major factor to control penetration depth and to occur spatter. It was found that the losses of laser energy by optic parameter and sticked spatter affect seriously laser weldability of thin sheets.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.125-128
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• 1995

The remote sleeve repair-welding technology using the pulsed Nd:YAG laser for increasing the lifetime of the steam generator tube in the nuclear power plant has been developed. The laser welding has many advantages on deep penetration depth and narrow heat affect zone(HAZ). The inconel 600 tube and inconel 690 sleeve used high temperature and high pressure service have been welded as round lap welds. It is found that the relation between the connection width and welding parameters. It is found that the shear strength in proportion to the connection width by conducting tensile-shear tests.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 E
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• pp.1864-1866
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• 1997

In this study, we designed the pulse superposition network consisting of a six-mesh and a three-mesh network, and fabricated the electrical power supply and the single elliptical resonator. We have developed a tec.bnique forming the step-pulse shape of pulsed Nd:YAG laser by using one shot multivibrater and have studied on the effect of two pulses superposition for the output and efficiency improvement of pulsed Nd:YAG laser by superposing a sinusoidal pulse on a main pulse.

• 한국레이저가공학회:학술대회논문집
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• 한국레이저가공학회 2000년도 추계학술발표대회 논문개요집
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• pp.7-9
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• 2000

• 한국레이저가공학회:학술대회논문집
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• 한국레이저가공학회 1999년도 추계학술발표대회 논문개요집
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• pp.39-42
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• 1999

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 영호남학술대회 논문집
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• pp.74-77
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• 2000

A pulsed Nd:YAG laser has been used in a wide variety of fields : measuring, material processing and so on. In a material processing, it is very important to control the laser energy density. A pulse repetition rate and a pulse width are regarded as the most dominant factors to control the energy density of laser beam. In this study, pulsed Nd:YAG laser system was designed and manufactured to control the laser output usefully and easily. This system adopted the sequential charge and discharge circuit is controlled by 80196 micro- processor. As a result, it is found that laser output is controlled minutely by changing laser input and pulse repetition rate, and usefully by using 80196 microprocessor.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2005년도 후기학술대회논문집
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• pp.25-26
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• 2005

This study suggested the occurrence source of weld-defects and its solution methods in a welding of Electrolyte injection hole by pulsed Nd:YAG laser. In experiment, the ramp down was used in order that solidification crack was removed. Furthermore, shrinkage stress and heat input were reduced by changing of weld trajectory and defocused distance. As a results of a experiment, a sound weld bead shape and crack-free weld bead can be obtained.