1996 Fiscal Year Final Research Report Summary
Monitoring of Laser Materials Processing
| Project/Area Number |
07455288
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Material processing/treatments
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| Research Institution | Osaka University |
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Principal Investigator |
OHJI Takayoshi Osaka University, Faculty of Eng., Professor, 工学部, 教授 (00089880)
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| Co-Investigator(Kenkyū-buntansha) |
OHKUBO Akira Osaka University, Faculty of Eng., Assistant, 工学部, 助手 (40260632)
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| Project Period (FY) |
1995 – 1996
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| Keywords | Laser Materials Processing / Monitoring / Key-hole / Laser Plasma Plume / IR Plasma Diagnostic Method / CO_2 Laser |
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| 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.
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