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1996 Fiscal Year Final Research Report Summary

Monitoring of Laser Materials Processing

Research Project

Project/Area Number 07455288
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section一般
Research Field Material processing/treatments
Research InstitutionOsaka University

Principal Investigator

OHJI Takayoshi  Osaka University, Faculty of Eng., Professor, 工学部, 教授 (00089880)

Co-Investigator(Kenkyū-buntansha) OHKUBO Akira  Osaka University, Faculty of Eng., Assistant, 工学部, 助手 (40260632)
Project Period (FY) 1995 – 1996
KeywordsLaser Materials Processing / Monitoring / Key-hole / Laser Plasma Plume / IR Plasma Diagnostic Method / CO_2 Laser
Research Abstract

A new method of plasma diagnostics, based on the continuous radiation theory of plasma, has been proposed in the previous papers, and it has been clarified that the method, called "IR plasma diagnostics method", is useful for the measurement of electron density of high density and low temperature plasma, such as arc plasma.
In the first part of this study, the electron density profile of Ar-shielded gas tungsten arc has been discussed precisely by using the method, and it is made clear that the density profile of high current Ar-shielded GTA has an off-axis peak in the zone near cathode, which corresponds to the peak electron density of Ar-plasma, expected at 17000K under thermal equilibrium condition.
In the second part, the diagnostic method has been applied to analyze the property of laser induced plasma in CO_2 laser welding. It is clarified that the plasma induced by CO_2 laser beam is a high density plasma and its peak density is higher than 10^<23> [m^<-3>], and the density is high enough for laser plume to absorb partially CO_2 laser beam power.
Accordingly, it is concluded that the IR method offers a simple and powerful means of laser plasma diagnostics and laser process monitoring.

  • Research Products

    (8 results)

All Other

All Publications (8 results)

  • [Publications] Ohji, T.: "Measurement of plasma plume in laser welding by IR radiation" Laser Materials Processing. 80. 729-738 (1995)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Ohji, T.: "Measuement of arc plasma by the IR plasma deagnostic method" International Inst. of Welding IIW Doc. 212-881-95. 1-11 (1995)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 松廣克之他: "高エネルギ密度ビーム溶接におけるキ-ホール形成限界について" 溶接学会論文集. 13. 218-222 (1995)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 黄地尚義: "溶接・接合プロセスの基礎" 産報出版, 262 (1996)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Takayoshi OHJI,et al.: "Measurement of plasma plume in laser welding by IR radiation" Laser Materials Processing. Vol.80. 729-738 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Takayoshi OHJI,et al.: "Measurement of arc plasma by the IR plasma diagnostic method" International Institute of Welding. IIW Doc.212-881-95. 1-11 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Yoshiyuki MATSUHIRO,et al.: "Study on keyhole formation of laser welding" Quarterly J.of Japan Weld.Soc.Vol.13 (in Japanese). 218-222 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Takayoshi OHJI: Fundamentals of Welding Processes. Sanpo Pub.Inc. (in Japanese), (1996)

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 1999-03-09  

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