• Title/Summary/Keyword: $CO_2$ 레이저 용접

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Comparison of Theoretical model with Experiment in Bead Shape of Laser Welding (레이저 용접의 비드 형상에 대한 실험치와 이론 결과의 비교)

  • Kim, J.D.;Kim, J.D.
    • Journal of the Korean Society for Precision Engineering
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    • v.11 no.1
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    • pp.201-210
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    • 1994

  • A theoretical heat-flow model incorporating with a constant moving CO$_{2}$ laser beam has been analyzed to predict depth and the shape of bead section during last beam welding. The laser beam is exponentially attenuated with an abosrption coefficient in the material. The solution can be expressed in terms of normalized variables. The experimental data were generated by usint CW 2 CO$_{2}$ laser with multi beam mode and CW 3 kW CO$_{2}$laser with Gaussian mode. The specimens were made as bead-on-plate welds for SM 10C, STS 304, STS 316, STS 420 and pure Nickel. The maximum possible penetration depth and the shape of beas section for given sources of laser power, travel speed and beam spot size can be prdicted with this model in a given material.

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Study on the Relationship Between Emission Signals and Weld Defect for In-Process Monitoring in CO2 Laser Welding of Zn-Coated Steel (아연코팅 강판의 CO2 레이저용접시 인프로세스 모니터링을 위한 측정신호와 용접결함과의 관련성 연구)

  • Kim, Jong-Do;Lee, Chang-Je
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.34 no.10
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    • pp.1507-1512
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    • 2010

  • In this study, the plasma induced by $CO_2$ laser lap welding of 6t Zn coated steel used for ship building was measured using photodiodes and a microphone. Then, the welding phenomenon with gap clearance of lap joint was compared with RMS-treated signal. Thus, we found that intensity of the RMS-treated signal increased with Zn vaporization; further, the presence of defects results in rapid variations with the RMS value as a function of lap-joint parameters. Besides, the FFT value of the raw signal with variations of changing welding parameters was calculated, and then the calculated FFT frequency value was set as the bandwidth of digital filter for a more accurate in-process monitoring. The RMS values were acquired by filtering the raw signal. By matching the weld beads and the calculated RMS values, we confirmed that there is a strong relationship between the signals and the defects.

  • https://doi.org/10.3795/KSME-A.2010.34.10.1507 인용 PDF KSCI