Experimental studies of the distortions of displacement of the laser beam radiated from the surface of a model body in a supersonic flow

2021 ◽  
Author(s):  
Dmitri A. Marakasov ◽  
Artem A. Sukharev ◽  
Ruvim S. Tsvyk
Keyword(s):  
Supersonic Flow ◽  
Laser Beam ◽  
Experimental Studies

scholarly journals INCREASING THE EFFICIENCY OF SURFACE STRENGTHENING OF METAL PRODUCTS BY COMBINED THERMODEFORMATION PROCESSING

2020 ◽  
pp. 103-110
Author(s):  
Oleksandr Danyleiko ◽  
Vitaliy Dzhemelinskyi ◽  
Dmytro Lesyk ◽  
Artemii Bernatskyi
Keyword(s):  
Surface Layer ◽  
Laser Beam ◽  
Surface Hardening ◽  
Thermal Deformation ◽  
Experimental Studies ◽  
Numerical Control ◽  
Surface Plastic ◽  
Beam Diameter ◽  
Metal Products ◽  
Deformation Surface

The article discusses the prospects of using combined thermal deformation surface processing to improve the performance properties of metal products. There is a new method of thermal deformation surface hardening (shot peening (SP) followed by laser heat treatment (LHT)) for tools and crown housings operating under difficult conditions proposed. For carrying out experimental studies, flat samples of 30KhGSA steel and steel 45 were selected. Preliminary hardening and finishing with static or dynamic methods of surface plastic deformation were carried out on a modernized installation based on a DYNAMITE 2800 numerical control machine, and SP was implemented on industrial equipment. Laser surface hardening of the samples was carried out in single passes with a sample moving speed of 300...500 mm/min with a laser beam diameter of 7.3 mm and a laser power of 1 kW using the ROFIN-SINAR DY 044 technological unit. The optimal regimes of surface hardening are determined under the deformation action of a gas-dynamic flow with solid particles and thermal action by a laser beam to obtain maximum values ​​of hardening depth and hardness. In particular, with SP, the gas-feed stream feed pressure is 0.5 MPa, the processing time is 1 min, regardless of the type of material. The optimal laser beam power is 1 kW at a sample travel speed of 300 mm/min. There are the results of experimental studies of the change in the hardening depth as a function of time and pressure after SP, the speed of movement of the treated sample from carbon steel 45 and medium alloyed steel 30KhGSA after LHT and combined SP+LHT, and also the distribution of microhardness over the depth of the hardened layer presented. It is revealed that the combined SP+LHT of 30 KhGSA steel at optimal modes forms 1.5 times (1.3 mm) greater depth of the strengthened surface layer in comparison with LHT, while providing the surface layer hardness of ~5400 MPa.

Quantifying Powder Losses and Analyzing Powder Conditions in order to Determine Material Efficiency in Laser Beam Melting

2016 ◽  
Vol 856 ◽  
pp. 231-237 ◽  
Author(s):  
Max Lutter-Günther ◽  
Alexander Hofmann ◽  
Christoph Hauck ◽  
Christian Seidel ◽  
Gunther Reinhart
Keyword(s):  
Laser Beam ◽  
Experimental Studies ◽  
Manufacturing Processes ◽  
Ecological Evaluation ◽  
Powder Bed ◽  
Material Efficiency ◽  
Laser Beam Melting ◽  
Measurement Results ◽  
Subtractive Manufacturing ◽  
End Use

Laser Beam Melting (LBM) is an additive manufacturing process, which is increasingly applied for the production of end use parts. One advantage of this powder bed fusion technology lies in the high material efficiency in comparison with subtractive manufacturing processes (i. e. milling, lathing). However, only few experimental studies have been conducted on the material efficiency of LBM. For the accurate evaluation of the LBM material efficiency, empirical values for powder losses are required. Furthermore, a lack of terminology for waste types and powder conditions in the context of LBM impedes communication and research on the topic. The presented paper aims to increase the understanding of material efficiency and powder conditions in Laser Beam Melting. A quantitative analysis of waste types is presented for different LBM application scenarios. This sets a basis for the ecological evaluation and comparison with conventional manufacturing processes. In order to achieve the aim, a terminology is introduced for waste types and powder conditions in the context of powder bed-based additive processes. Therefore, considerations regarding powder quality are taken into account. For the quantification of powder losses, the experimental setup and measurement results are described. Furthermore, loss types and their significance are analyzed and discussed.

Experimental studies of surface relief gratings on polymer Films

1995 ◽  
Vol 413 ◽  
Author(s):  
X. L. Jiang ◽  
D. Y. Kim ◽  
L. Li ◽  
V. Shivshankar ◽  
J. Kumar ◽  
...  
Keyword(s):  
Laser Beam ◽  
Polymer Films ◽  
Surface Relief ◽  
Experimental Studies ◽  
Laser Beams ◽  
Recording Conditions ◽  
Surface Modulation ◽  
High Diffraction Efficiency ◽  
Surface Relief Gratings ◽  
High Diffraction

ABSTRACTWe report our investigation on the recording of surface relief gratings on azobenzene containing polymer films by laser beams with different polarizations. Experimental evidence shows that it is necessary to have spatial variations of both magnitude and direction of net electric field in the films to record surface relief gratings. Large surface modulation (> 3500 Å) and high diffraction efficiency (about 30%) were obtained under optimized recording conditions. In addition, polarization dependent erasure of the gratings by a single laser beam has been studied.

Experimental Study on Laser Beam Sealing for Increased Format-Flexibility of Packaging Machines

2017 ◽  
Vol 871 ◽  
pp. 199-207
Author(s):  
Georg Götz ◽  
Martin Brugger ◽  
Nicholas Amthor ◽  
Christoph Richter ◽  
Gunther Reinhart
Keyword(s):  
Experimental Study ◽  
Energy Efficiency ◽  
Laser Beam ◽  
Laser Beam Welding ◽  
Experimental Studies ◽  
Surface Structures ◽  
Fibre Laser ◽  
Key Factors ◽  
Processing Technologies ◽  
Diode Pumped

Resource and energy efficiency as well as format-flexibility are important key-factors for users and manufacturers of packaging machines. These key-factors could be enhanced together due to a generally positive interconnection. For example, increased format-flexibility reduces the stand-by phases and improves the overall equipment effectiveness (OEE). One way to achieve these objectives is using more flexible processing technologies. Laser beam welding is a widespread technology in many industrial branches. Use of this technology in packaging machines for sealing is unknown and therefore the potential of this technology for increasing format-flexibility as well as resource and energy efficiency is not yet exploited. The focus of this paper is the experimental investigation of laser beam sealing with a 2 μm diode-pumped thulium fibre laser. The results of various experimental studies will be presented. The achievable sealed-seam strengths with different laser beam outputs are demonstrated. Furthermore, reasons for different peeling conditions of these sealing seams are investigated. Different materials and surface structures of the required workpiece carrier are experimentally evaluated.

Modeling and Characterization of Laser Drilling of Small Holes on Metal Sheets

2004 ◽  
Author(s):  
Wei Han ◽  
Ryszard J. Pryputniewicz
Keyword(s):  
Laser Beam ◽  
Manufacturing Industry ◽  
Pulse Length ◽  
Experimental Studies ◽  
Laser Drilling ◽  
Melting Front ◽  
Laser Parameters ◽  
Metal Sheets ◽  
Small Holes ◽  
Melt Ejection

Laser drilling is increasingly being used in fabrication of small components in various materials with applications in aerospace, automotive, electronics and medical industries, and it offers a unique combination of benefits for the contemporary manufacturing industry as a rapid, precise, clean, flexible, and efficient process. Laser drilling involves a stationary laser beam which uses its high power density to melt or vaporize material from the workpiece, and the process is governed by an energy balance between the irradiating energy from the laser beam, the conduction heat into the workpiece, the energy losses to the environment, and the energy required for phase change in the workpiece. There are three major mechanisms of removal of material from the beam interaction zone and consequent propagation of the melt front into the metal bulk. They are (1) melt ejection due to interaction between the melt and an assisting gas, (2) melt ejection by the vaporization-induced recoil force, and (3) melt evaporation. The results of laser drilling processes, such as the profile of the heat affected zone (HAZ) and the geometry of the holes, strongly depend on settings of the laser parameters such as peak power, pulse length, pulse repetition rate, number of pulses, focal condition, etc. In addition, the processing results are strongly influenced by geometrical and material properties of the workpiece. This paper presents theoretical and experimental studies of laser drilling of micrometer size holes on metal sheets using a pulsed Nd:YAG laser. A model of the temperature distribution and the motion of the melting front for laser drilling is presented and compared with experimental data. Effects of laser parameters on the resultant geometry of the hole are investigated and summarized, and an optimum procedure for laser drilling of small holes on metal sheets is outlined.

scholarly journals Studies of thin foils acceleration by pulsed laser beam

1988 ◽  
Vol 6 (2) ◽  
pp. 327-334 ◽  
Author(s):  
I. N. Burdonsky ◽  
A. L. Velikovich ◽  
V. V. Gavrilov ◽  
A. Yu. Gol'tsov ◽  
E. V. Zhuzhukalo ◽  
...  
Keyword(s):  
Laser Beam ◽  
High Speed ◽  
Experimental Studies ◽  
Thin Wall ◽  
Plasma Parameters ◽  
Absorption Mechanism ◽  
Laser Plasma Interaction ◽  
Thin Foils ◽  
Plasma Corona ◽  
Cumulative Jets

Experimental studies of the ablative acceleration of thin foils as carried out on the “Mishen” device (Nd laser, λ = 1·06μm, 3 nsec pulses) are reported. The plasma corona in the range of power densities 1013–1014 W/cm2 is shown to absorb 80–90% of the laser beam energy, the classical collisional absorption mechanism being the main one. Jet-like and filamentary structures are observed in the laser-plasma interaction; however, the main plasma parameters are found to be independent of the presence (or absence) of such structures. The measured hydrodynamic efficiency of stable ablative acceleration in plane geometry is ≲5%. The production of high-speed cumulative jets with irradiated thin-wall hollow conical targets is reported as an example of a non-traditional ablative acceleration geometry.

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