Characteristics of stably induced laser plasma

Tsukamoto, Shiro; Hiraoka, Kazuo; Asai, Yoshikazu; Irie, Hirosada; Yoshino, Masao; Shida, Tomohiko

doi:10.2351/1.5059028

Cited by 7 publications

(8 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Extensive research has been carried out to measure the temperature of the plasma during CO 2 laser welding using spectroscopic methods. [17][18][19][20][21][22][23][24] However, it is not easy to accurately measure the local plasma temperature due to fluctuations in the plasma during welding. Most of the studies focused on spatially averaged plasma temperature or local temperature using the stably induced laser plasma.…”

Section: Monochromatic Imagementioning

confidence: 99%

“…Most of the studies focused on spatially averaged plasma temperature or local temperature using the stably induced laser plasma. 17,18,24 High speed monochromatic imaging technique allows us to measure the accurate local plasma temperature. 25,26 Figure 1 describes the methodology.…”

Section: Monochromatic Imagementioning

confidence: 99%

“…Since the wavelength of the CO 2 laser is 10 times greater than that of solid state lasers, the plasma temperature is much higher and the plasma significantly affects the welding behaviour during CO 2 laser welding. Extensive research has been carried out to measure the temperature of the plasma during CO 2 laser welding using spectroscopic methods 17 – 24. However, it is not easy to accurately measure the local plasma temperature due to fluctuations in the plasma during welding.…”

Section: Monochromatic Imagementioning

confidence: 99%

“…However, it is not easy to accurately measure the local plasma temperature due to fluctuations in the plasma during welding. Most of the studies focused on spatially averaged plasma temperature or local temperature using the stably induced laser plasma 17, 18, 24…”

Section: Monochromatic Imagementioning

confidence: 99%

See 3 more Smart Citations

High speed imaging technique Part 2 – High speed imaging of power beam welding phenomena

Tsukamoto¹

2011

Science and Technology of Welding and Joining

View full text Add to dashboard Cite

The high speed imaging technique is an attractive tool to elucidate welding phenomena. In this paper, applications of this technique are reviewed in order to understand the power beam welding phenomenon. Monochromatic imaging technique, which can take pictures of plasma with any specific spectrum wavelength, is used to analyse state of the laser induced plasma and distribution of some species, such as ions and atoms of gases and metals. During electron beam welding, intermittent melting process and spiking phenomenon can be clearly recorded by a pinhole X-ray streak camera. The in situ X-ray transmission imaging system is useful to observe the dynamic keyhole and fluid flow behaviour, which cannot be directly observed by any other method. High speed observations of the solidification front clearly show the solidification cracking process. In the present paper, methods to analyse the solidification cracking using high speed imaging are also described.

show abstract

Section: Monochromatic Imagementioning

confidence: 99%

Section: Monochromatic Imagementioning

confidence: 99%

Section: Monochromatic Imagementioning

confidence: 99%

Section: Monochromatic Imagementioning

confidence: 99%

See 2 more Smart Citations

High speed imaging technique Part 2 – High speed imaging of power beam welding phenomena

Tsukamoto¹

2011

Science and Technology of Welding and Joining

View full text Add to dashboard Cite

show abstract

“…The first term on the right-hand side of equation ( 2) represents the rate of energy absorption by the plume. This term is obtained from the Beer-Lambert law by considering the plume as the attenuating medium [16]. The second term corresponds to the rate of loss of energy from the plasma to the surroundings due to the radiation and convection effects that are combined by defining an effective heat-transfer coefficient h eff as follows:…”

Section: The Plasma Kinetic Modelmentioning

confidence: 99%

Nonlinear effects of laser-plasma interaction on melt-surface temperature

Sankaranarayanan

Kar

1999

J. Phys. D: Appl. Phys.

View full text Add to dashboard Cite

A plume consisting of vapour and ionized particles of the workpiece is usually formed during various types of laser materials processing. The characteristics of this plume depend on a large number of parameters such as the laser power, spot size, scanning speed, material properties and shielding gas. The height, radius, temperature and absorption coefficient of the plasma are calculated for various values of process parameters. The surface temperature of the melt pool and the vaporization rate are also calculated on the basis of the Stefan condition at the liquid-vapour interface. The absorption coefficient of the plasma given by the Kramers-Unsöld relation and the ionization fraction given by the Saha-Eggert equation are used to model the laser beam propagation through the plasma. A detailed analysis of the plasma stability indicates that absorption of the laser beam by the plasma affects the melt-pool surface temperature nonlinearly.

show abstract

Energy loss in the plasma during laser drilling

Sankaranarayanan¹,

Emminger²,

Kar³

1999

J. Phys. D: Appl. Phys.

View full text Add to dashboard Cite

A plume consisting of vapour and ionized particles from the workpiece is commonly formed during various types of laser materials processing. The process parameters such as the laser power, spot diameter, scanning speed, material properties and shielding gas affect the properties of the vapour-plasma plume. A mathematical model is presented in this paper to predict the plasma properties, such as its temperature and absorption coefficient, and the partitioning of laser energy between the plasma and workpiece for different process parameters. The effect of plasma on the surface temperature of the liquid metal and the vaporization rate are modelled using the Stefan condition at the liquid-vapour interface. A new experimental technique named as the pinhole experiment is presented in this paper to measure the partitioning of laser energy between the plasma and the workpiece.

show abstract

Characteristics of stably induced laser plasma

Cited by 7 publications

References 4 publications

High speed imaging technique Part 2 – High speed imaging of power beam welding phenomena

High speed imaging technique Part 2 – High speed imaging of power beam welding phenomena

Nonlinear effects of laser-plasma interaction on melt-surface temperature

Energy loss in the plasma during laser drilling

Contact Info

Product

Resources

About