• Title/Summary/Keyword: YAG-Laser

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Influence of process parameters on the kerfwidth for the case of laser cutting of CSP 1N sheet using high power CW Nd:YAG laser (고출력 연속파형 Nd:YAG 레이저를 이용한 CSP 1N 냉연강판 절단시 절단공정변수의 절단폭에 미치는 영향)

  • Ahn, Dong-Gyu;Kim, Min-Su;Lee, Sang-Hoon;Park, Hyung-Jun;Yoo, Young-Tae
    • Proceedings of the KSME Conference
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    • 2004.11a
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    • pp.910-915
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    • 2004
  • The objective of this study is to investigate the influence of process parameters, such as power of laser, travel speed of laser and material thickness, on the practical cutting region and the kerfwidth for the case of cutting of CSP 1N sheet using high power Nd:YAG laser with continuous wave(CW). In order to find the practical cutting region and the relationship between process parameters on the kerfwidth, several laser cutting experiments are carried out. The effective heat input is introduced to consider the influence of power and travel speed of laser on the kerfwidth together. From the results of experiments, the allowable cutting region and the relationship between the effective heat input and kerfwidth for the case of cutting of CSP 1N sheet using high power CW Nd:YAG laser have been obtained to improve the dimensional accuracy of the cut area.

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Investigation of Zircaloy-4 weldability using a pulsed Nd:YAG laser (펄스형 Nd:YAG 레이저를 이용한 지르칼로이-4 용접특성 조사)

  • 김수성;김덕현;김철중;이종민
    • Journal of Welding and Joining
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    • v.9 no.1
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    • pp.23-31
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    • 1991
  • Laser beam weldability of zircaloy-4was investigated using a pulsed Nd: YAG laser of 200W average power. Mechanical properties of laser and GTA bead-on-plate welded zircaloy-4 test specimens were compared. The influence of plasma generated during laser welding was analyzed and optimum laser welding parameters were investigated.

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Laser Diode Pumped Mode-Locked $1.3{\mu}m$ Nd-YAG Laser (모드록킹된 다이오드 여기 $1.3{\mu}m$ Nd:YAG 레이저)

  • Lee, Young-Woo
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2007.10a
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    • pp.271-274
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    • 2007
  • 본 연구는 $1.3{\mu}m$ 파장의 초고속 Nd:YAG레이저 펄스를 얻기 위해 AOM을 이용하여 모드록킹 Nd:YAG레이저 공진기를 구성하였다. 여기용 반도체 레이저는 중심파장 810nm, 출력 1.2W이며, 레이저 매질은 직경 3mm, 길이 10mm로 $Nd^{3+}$가 1.0at%로 도핑된 Nd:YAG Rod를 사용하였다. 모드록킹에는 음향광학 변조기(변조 주파수 40MHz)를 사용하여 펄스폭 ${\tau}p=80ps$의 극초단 펄스를 얻었다.

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Analysis of Beam Quality of the Unsymmetric Nd : YAG Laser with Unstable Resonator (비대칭 구조로 이루어진 불안정 공진기형 Nd : YAG 레이저의 빔질 분석)

  • Kim, Hyun-Su
    • Korean Journal of Optics and Photonics
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    • v.16 no.5
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    • pp.456-461
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    • 2005
  • We numerically investigate the characteristic of single Nd:YAG rod laser with the convex-plane resonator configuration in order to get the best condition for high efficient intra-cavity second harmonic generation(SHG). The beam quality is analyzed with ABCD matrixes including the thermal lensing characteristic of Nd:YAG rod. The analysis is focused on stability, M2, beam waist and mode-volume of laser beam inside the resonator. The best conditions for SHG is obtained when a laser rod is set near the curved laser mirror.

Measurement of excitation efficiency and passively Q-switched characteristics of laser diode end-pumped Nd:YAG laser by using $Cr^{4+}$:YAG as a saturable absorber ($Cr^{4+}$:YAG 포화 흡수체를 이용한 레이저 다이오드 뒷면 여기 Nd:YAG 레이저의 들뜸 효율 및 Q-switching 특성 연구)

  • 정태문;김광석;문희종;이종훈;김철중;이종민
    • Korean Journal of Optics and Photonics
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    • v.9 no.4
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    • pp.231-235
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    • 1998
  • Passively Q-switched, laser diode(LD) end-pumped Nd:YAG laser was demonstrated by using $Cr^{4+}$:YAG as a saturable absorber. In addition , we could calculate an excitation efficiency, which is an important parameter to evaluate the pumping geometry, directly by measuring the absorbed power in Nd:YAG at threshold condition. We found that output parameters such as average power, pulse duration, and repetition rate strongly depended on the low intensity transmission of $Cr^{4+}$:YAG and driving current of lase diode. The maximum Q-switched output power of 1 W was obtained with 40 kHz repetition rate. The pulse duration was varied from 50 ns to 200 ns.

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The Digital Controlled Implementation of the Resonant DC-DC Converter with High Voltage, High Frequency For Pulsed Nd:YAG Laser (고전압과 고주파수형 공진형 DC-DC 콘버터를 이용한 펄스형 Nd:YAG 레이저의 디지틸제어 구현)

  • Kim, Whi-Young
    • Proceedings of the IEEK Conference
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    • 2001.09a
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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.

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Process Parameters of Butt Welding of SM45C using a Continuous Wave Nd:YAG Laser Beam (연속파형 Nd:YAG 레이저를 이용한 SM45C 맞대기 용접의 공정 변수)

  • 유영태;노경보;오용석;김종신;임기건
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.7
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    • pp.44-55
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    • 2003
  • The Nd:YAG laser process is known to have high speed and deep penetration capability to become one of the most advanced welding technologies. This paper describes the machining characteristics of SM45C carbon steel welding by use of an Nd:YAG laser. In spite of its good mechanical characteristics, SM45C carbon steel has a high carbon contents and suffers a limitation in the industrial application due to the poor welding properties. The major process parameters studied in the present laser welding experiment were position of focus, travel speed and laser power. Optical microscope and SEM were used to investigate the microstructures of the welded zone. The experimental results showed that penetration depth of the welding process increases with laser power. Both the microstructural investigation and the theoretical calculations indicated that materials undergoes a very high heating and cooling cycle during welding process. It was also found that the austenite nucleation takes place at the initial stage and the completion temperature of austenite transformation is much higher than in the case of the arc welding.

Effect of Nd:YAG Laser Irradiation to Mental Region for Sensory Nerve Conduction Change (하악 이공부에 조사된 Nd:YAG 레이저가 감각신경전도변화에 미치는 영향)

  • Jeon, Jae-Woo;Kim, Kyoung-Hee;Ko, Myong-Yun;Ahn, Yong-Woo;Park, Jun-Sang
    • Journal of Oral Medicine and Pain
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    • v.30 no.4
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    • pp.447-455
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    • 2005
  • The purpose of this study was to examine the effect of Nd:YAG laser irradiation for sensory nerve conduction change. Nd:YAG laser was irradiated to mental region for 5 minutes with the parameters that 10 Hz and 20 Hz of 100 mJ/pulse. Target size of irradiation was 30 mm diameter of circle and target-tip distance was about 10 mm. Therefore, the power density were 212 $mW/cm^2$ and 424 $mW/cm^2$. Sensory nerve conduction was evaluated with $Neurometer^{\circled}$ CPT/C before and after Nd:YAG laser irradiation. As an outcomes, the current perception threshold(CPT) and pain tolerance threshold(PTT) were obtained. We made a comparison of these two values and the results were as follows. 1. There was no significant difference in CPT at 1W, 10 Hz and 2 W, 20 Hz Nd:YAG laser irradiation. 2. There was no significant difference in PTT at 10 Hz, 20 Hz of 100 mJ/pulse Nd:YAG laser. 3. There were no significant differences in CPT and PTT between 1 W, 10 Hz group and 2 W, 20 Hz group. Therefore, We can make a conclusion that Nd:YAG laser irradiation to mental region have no effect on mental nerve conduction in our study model.

Cleaning of NiP Hard Disk Substrate Using Near-Infrared and Ultraviolet Irradiation of Nd:YAG Laser Pulses (Nd:YAG 레이저의 근적외선과 자외선 펄스를 이용한 NiP 하드디스크 기층의 세척)

  • ;C. P. Grigoropoulos
    • Laser Solutions
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    • v.4 no.2
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    • pp.39-45
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    • 2001
  • This paper introduces a cleaning process for removing submicron-sized particles from NiP hard disk substrates by the liquid-assisted laser cleaning technique. Measurements of cleaning Performance and time-resolved optical diagnostics are Performed to analyze the physical mechanism of contaminant removal. The results reveal that nanosecond laser pulses are effective for removing the contaminants regardless of the wavelength and that a thermal mechanism involving explosive vaporization of liquid dominates the cleaning process.

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