An algorithm of far-distance pulse laser energy density base on image processing

2012 ◽  
Author(s):  
Jin Duan ◽  
Xiaoman Wang ◽  
Huilin Jiang ◽  
Wenbo Jing
Keyword(s):  
Image Processing ◽  
Energy Density ◽  
Pulse Laser ◽  
Laser Energy ◽  
Laser Energy Density ◽  
Pulse Laser Energy

scholarly journals Pulse laser surface modification of poly-ether-ether-ketone for surface metallization

2021 ◽  
Vol 261 ◽  
pp. 02007
Author(s):  
Nan Wang ◽  
Jia-Feng Li ◽  
Jing-Ying Bai ◽  
Xu-Guang Wang ◽  
Li-Gong Zhang
Keyword(s):  
Energy Density ◽  
Pulse Laser ◽  
Laser Energy ◽  
Interaction Mechanism ◽  
Laser Energy Density ◽  
Future Application ◽  
Photothermal Effect ◽  
Application Range ◽  
Nickel Coatings ◽  
Laser Treatments

In order to broaden the application range, PEEK has been modified by 1064nm-wavelength pulse laser, then deposited with Ni-P alloys by electroless plating. The properties of metal layers on PEEK were characterized by SEM, resistance tester and metallographic microscope, respectively. When the laser energy density is relatively low (Q<60J·cm-2), there is mainly photothermal effect on the PEEK with laser, and the surface of the substrate presents periodic undulating groove structure with a small number of holes. When the laser energy density is rather higher (Q≥60J·cm-2), there are simultaneously enhanced photothermal effect and partial photochemical effect. As a result, the surface of PEEK is uniformly covered with melted layer or re-solidified product after melting. Besides, the nickel coatings on the PEEK have been dense, uniform and in good adhesion with the substrate for the sample after laser treatments (Q>10J·cm-2), of which the surface resistance of the coating is less than 20 mΩ. In this paper, the interaction mechanism of the pulse laser on PEEK has been studied and the metals on the PEEK have been prepared under the laser-induced effect, which provides technical support for the future application of PEEK in aviation with aerospace fields, such as, radar and antenna.

Pulse-to-Pulse Laser Stability Effects on Multiple Shot Excimer Laser Crystallized a-Si Thin Films

1994 ◽  
Vol 343 ◽  
Author(s):  
R. I. Johnson ◽  
G. B. Anderson ◽  
J. B. Boyce ◽  
D. K. Fork ◽  
P. Mei ◽  
...  
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Energy Density ◽  
Pulse Laser ◽  
Laser Fluence ◽  
Laser Energy ◽  
Laser Energy Density ◽  
Distribution Profile ◽  
X Ray ◽  
Silicon Thin Films

ABSTRACTLaser crystallized amorphous silicon thin films on quartz exhibit a peak in the grain size, electron mobility and the Si (111) x-ray intensity as a function of the laser fluence, substrate temperature, film thickness, and the number of laser shots per unit area. The peak in grain size has also been shown to be dependent: on the stability of the pulse-to-pulse laser energy density, particularly at high shot densities. The shape of the distribution profile of the pulse-to-pulse laser fluence can significantly alter the grain growth at higher shot densities. The modified growth can be expressed by a simple model based on the mean and standard deviation of the laser energy density relative to the characteristic fluence at which the grain size, mobility, and Si (111) x-ray intensities are maximized.

Fundamentals of radiation heat transfer in AlSi10Mg powder bed during selective laser melting

2019 ◽  
Vol 25 (9) ◽  
pp. 1506-1515 ◽  
Author(s):  
Pei Wei ◽  
Zhengying Wei ◽  
Zhne Chen ◽  
Jun Du ◽  
Yuyang He ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Energy Density ◽  
Negative Impact ◽  
Laser Energy ◽  
Melting Process ◽  
Laser Energy Density ◽  
Granular System ◽  
Laser Melting ◽  
Content Type ◽  
Powder Bed

Purpose This paper aims to study numerically the influence of the applied laser energy density and the porosity of the powder bed on the thermal behavior of the melt and the resultant instability of the liquid track. Design/methodology/approach A three-dimensional model was proposed to predict local powder melting process. The model accounts for heat transfer, melting, solidification and evaporation in granular system at particle scale. The proposed model has been proved to be a good approach for the simulation of the laser melting process. Findings The results shows that the applied laser energy density has a significantly influence on the shape of the molten pool and the local thermal properties. The relative low or high input laser energy density has the main negative impact on the stability of the scan track. Decreasing the porosity of the powder bed lowers the heat dissipation in the downward direction, resulting in a shallower melt pool, whereas pushing results in improvement in liquid track quality. Originality/value The randomly packed powder bed is calculated using discrete element method. The powder particle information including particle size distribution and packing density is taken into account in placement of individual particles. The effect of volumetric shrinkage and evaporation is considered in numerical model.

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