scholarly journals Thermophysical analisis of modification of the surface of the workpiece by laser radiation

2019 ◽  
pp. 92-98
Author(s):  
M. N. Vereschagin ◽  
S. N. Tselueva ◽  
M. Yu. Tseluev
Keyword(s):  
Laser Radiation ◽  
Radiation Power ◽  
Scanning Speed ◽  
Heat Propagation ◽  
Temperature Fields ◽  
Straight Line ◽  
Beam Section ◽  
Distribution Of Power ◽  
Distribution Of Power Density ◽  
Modification Of The Surface

The paper presents a thermophysical analysis of modifying the surface of a workpiece by laser radiation due to the melting of a layer of a doping substance previously deposited on the surface of the base metal.The process of heating a two-layer metallic system with a laser pulse with a normal distribution of power density over the beam section is considered. Under the action of a heat source of constant power, moving in a straight line at a constant speed, the process of heat propagation tends to the limiting quasistationary state, when the temperature field does not change with time and moves along with the source.The dependences obtained allow us to estimate the effect of the laser treatment mode on the distribution of temperature fields, establish the patterns of heat propagation and relate them to phase transformations in the metal.It has been established that the technological modes of exposure to laser radiation are limited by the value of the energy per pulse from 4 to 12 J. The choice of technological modes of exposure is determined by the combination of the scanning speed of the laser beam and the radiation power.

scholarly journals Hydrophobization of Metal Surfaces

2019 ◽  
Vol 8 (4) ◽  
pp. 6715-6720
Keyword(s):  
Laser Radiation ◽  
Radiation Power ◽  
Scanning Speed ◽  
Pulse Frequency ◽  
Wetting Angle ◽  
Laser Spot ◽  
Spot Diameter ◽  
Laser Impact ◽  
Laser Beam Scanning ◽  
Laser Spot Diameter

This work describes possibility to create texturized surfaces by their modification using laser equipment with the aim to achieve steady heterogeneous wetting regime. Experimental results regarding the influence of laser radiation variables on wetting angle are given for steel (20Kh13) and aluminum (D16T) surfaces. This was aided by variation of main variables of laser impact, namely: radiation power (from 10 to 20 W), laser beam scanning speed (from 100 to 500 mm/s), pulse frequency (from 20 to 80 kHz). Analysis of the results has revealed that the maximum wetting angles for steel and aluminum surfaces are 147.64° and 150.27°, respectively, they have been obtained upon laser texturizing at the same variables of laser radiation. The influence of laser spot diameter on wetting angle has been determined upon impact on steel (20Kh13) surface. This has been aided by lenses the with focal lengths of 163 and 100 mm, their laser spot diameters are 59 and 25 µm, respectively. It has been revealed that, other conditions being equal, the wetting angles are higher at higher laser spot diameter (59 µm).

Metal-coated fiber sensor for laser radiation power measurements

2019 ◽  
Vol 58 (07) ◽  
pp. 1 ◽  
Author(s):  
Ivan Khramov ◽  
Renat Shaidullin ◽  
Oleg Ryabushkin
Keyword(s):  
Laser Radiation ◽  
Radiation Power ◽  
Fiber Sensor ◽  
Laser Radiation Power ◽  
Coated Fiber ◽  
Power Measurements

Ultrafast Imaging of Ultraviolet Laser Ablation and Etching of Polymethyl Methacrylate

1989 ◽  
Vol 158 ◽  
Author(s):  
Bodil Braren ◽  
R. Srinivasan ◽  
Kelly G. Casey ◽  
Mildred Yeh
Keyword(s):  
Laser Radiation ◽  
Polymethyl Methacrylate ◽  
Initial Velocity ◽  
Average Velocity ◽  
Solid Material ◽  
Low Molecular Weight ◽  
Molecular Weight Polymer ◽  
Ultrafast Imaging ◽  
Visible Laser ◽  
Modification Of The Surface

ABSTRACTAblation and etching of the surface of polymethyl methacrylate (=PMMA) by pulses of 248 nm laser radiation ∼20 ns full width at half maximum (FWHM) have been probed by pulses of visible laser radiation (596 nm; < 1 ns FWHM). The results were recorded photographically in real time with a set time delay between the 248 nm ablation pulse and the 596 nm probe pulse. Modification of the surface structure of the polymer at a fluence ∼ 3 J/cm2 is first visible at 12 ns and appears to be complete in ∼ 60 ns. The first manifestation of the ablation does not occur until the UV pulse is over and consists of a nearly transparent shock-wave that has an initial velocity of 6 ∼ 104 cm/sec. Solid material from the ablated zone begins to leave the surface at ∼150 - 200 ns and reaches a maximum in intensity at 6 µs, continuing for ∼ 20 µs. The average velocity of the solid material, which is probably a low molecular weight polymer of PMMA, is 1.5 ∼ 104 cm/sec. The conclusion to be drawn from the present work is that the signal measured by photoacoustic detectors does not coincide with the bulk of the material leaving the surface.

National Primary Standard for the Unit of Average Laser Radiation Power Get 28–2013

2016 ◽  
Vol 58 (11) ◽  
pp. 1195-1199
Author(s):  
A. A. Kovalev ◽  
A. A. Liberman ◽  
A. S. Mikryukov ◽  
S. A. Moskalyuk ◽  
M. V. Ulanovskii
Keyword(s):  
Laser Radiation ◽  
Radiation Power ◽  
Primary Standard ◽  
Laser Radiation Power ◽  
National Primary Standard ◽  
Average Laser

Instrument for measuring laser radiation power density

1975 ◽  
Vol 18 (10) ◽  
pp. 1452-1453
Author(s):  
M. I. Dukhanina ◽  
G. I. Rukman ◽  
E. A. Sokolov ◽  
A. V. Khromov
Keyword(s):  
Laser Radiation ◽  
Power Density ◽  
Radiation Power ◽  
Laser Radiation Power ◽  
Radiation Power Density
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