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Analysis and design of coaxial nozzle with rectangular outlet for high power diode laser in laser metal deposition
摘要： High power diode laser (HPDL) characterized by a wider rectangle beam spot (RBS) with top-hat intensity distribution is particularly applied in laser metal deposition to manufacture large-scale components. In order to design a coaxial nozzle with rectangular outlet to match the RBS of the HPDL, a novel wide-beam coaxial feeding nozzle (WBCFN) outlet is proposed. Based on the gas-powder flow model established in ANSYS FLUENT, the influence of structural parameters of the new coaxial nozzle on the gas flow and powder distribution is investigated. Two quantitative indexes are defined to seek out the optimal designing scheme that minimize the divergences of the powder flow and uniform the powder distribution in transverse and longitudinal directions. And then, the effect and sensitivity of structural parameters on concentration distribution and focal length of powder flow are analyzed. The results indicate that the two indexes increase with the increase of exit width, while the variance of concentration firstly increases and then decreases with the increase of the chamber length and inclination angle. The focal length decreases with the increase of inclination angle. Finally, the optimal solution of designing scheme is obtained through comprehensive analysis, and experiments are carried out to validate the model, which indicates that the designed WBCFN can acquire good morphology and quality of deposition layer for HPDL.
关键词： Wide-beam coaxial feeding nozzle,Laser metal deposition,Discrete phase model,High power diode laser
更新于2025-09-23 15:21:01
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Time-dependent 3D modeling of the thermal analysis of the high-power diode laser hardening process
摘要： In this paper, the thermal analysis of the high-power diode laser hardening process was modeled on AISI 4130 steel. Afterward, the depth and width of hardness were predicted based on the complete austenite temperature (AC3). Due to the dimensions and output beam power of the diode laser stack (DLS), it is impossible to achieve the suitable power density (103-105 W/cm2). Furthermore, the output intensity profile of the DLS is not homogeneous because of the pitch between the emitters. Thus, to achieve a suitable power density and a uniform beam profile, an optical layout was designed. The beam profile was experimentally obtained by a beam profiler at different distances from the focal plane and was compared with the modeling results. Due to the agreement between the modeling and experimental results, the intensity value of each mesh of the laser profile was extracted from the ZEMAX software. Then, for the thermal analysis of the laser hardening process (LHP), it was entered as a heat flux input into the COMSOL Multiphysics software.
关键词： Thermal analysis,Intensity profile,High power diode laser,Laser hardening,Complete austenite temperature
更新于2025-09-23 15:19:57
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Multi-Objective Optimization of High Power Diode Laser Surface Hardening Process of AISI 410 by means of RSM and Desirability Approach
摘要： In this research, laser surface hardening of AISI 410 was carried out by a high power diode laser based on Response Surface Method (RSM). Laser power, scanning speed, and focal plane position were evaluated as input process changeable while geometry dimensions of hardened zone (i.e., Depth and width of hardness), maximum hardness, Microhardness deviation (MHD) from base material in depth, and ferrite phase percentage in the microstructure were evaluated as process output Results. The effect of input parameters on the response variations were studied by statistical investigation. Results indicated that by increasing the laser power and decreasing other parameters, higher surface hardness with significant penetration, and least ferrite percentage would be reached by means of the desirability function approach. By using experimental tests, validation of optimized results was performed. In this research in the optimum conditions, the maximum hardness, maximum depth of hardness and minimum ferrite percentage were achieved 670 Vickers, 2.2 mm and 0.45%, respectively.
关键词： Laser Surface Hardening,High Power Diode Laser,Design of Experiments,Laser Materials Processing,Optimization
更新于2025-09-19 17:13:59
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Study of Optical Properties of Surface Layers Produced by Laser Surface Melting and Laser Surface Nitriding of Titanium Alloy
摘要： This study measured optical properties, such as specular, di?use, and total re?ection for 808 nm wavelength, characteristic for high power diode lasers radiation, from the surface of titanium alloy Ti6Al4V at delivery conditions, polished, and oxidized. Moreover, the optical properties of surface layers produced by high power direct diode laser (HPDDL) melting and nitriding were determined. Additionally, a methodology for determining the value of absorption for 808 nm wavelength of the HPDDL radiation on the surface of a melt pool during laser surface melting and nitriding of titanium alloy was proposed. The results show that the distinct di?erences in absorption a?ect the heat transfer, thermal conditions of laser heating and thereby the penetration depth during laser melting and nitriding of the titanium alloy.
关键词： high power diode laser,absorption,titanium nitrides,re?ectivity
更新于2025-09-16 10:30:52
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Use of high-power diode laser at 1060?nm for the treatment of vascular lesions
摘要： The use of 1060-nm wavelength light emitted from a high-power diode laser is a novel method for the removal of vascular lesions. Two Caucasian women with Fitzpatrick skin phototype II, who had various vascular lesions, were treated with a 1060-nm high-power diode laser, applying a fluence of 120 J/cm2 and a single pulse duration of 74 milliseconds. Immediate results were that the cherry angiomas became dark and a scab was formed (that remitted 2 weeks after treatment); the telangiectasias and venulectasias disappeared immediately. This technology has reported effective and safe results for removing different types of vascular lesions in the two patients treated. Side effects were those expected for this technique.
关键词： High-power diode laser,Nd: YAG,Venulectasias,Vascular lesions,Cherry angiomas,Telangiectasias
更新于2025-09-16 10:30:52
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Reducing the pitting susceptibility of AISI 304 stainless steel using a hybrid treatment of high-power diode laser and large pulsed electron beam irradiation
摘要： Large pulsed electron beam (LPEB) irradiation has been widely used for surface modification of metals, alloys, polymers, and composites due to its unique interaction mechanisms with materials. The rapid melting and resolidification processes during LPEB irradiation induce phase transformation at the resolidified layer, which enables a simultaneous improvement in mechanical characteristics and chemical stability of metals. However, the generation of craters during LPEB irradiation adversely affects surface quality. It is imperative to minimize crater formation following LPEB irradiation to mitigate pitting corrosion on the surface of stainless steel (SS). In this study, a hybrid surface modification approach using a high-power diode laser (HPDL) and LPEB is proposed to reduce the crater generation during LPEB irradiation. The size and density of craters generated during LPEB irradiation were effectively reduced following the HPDL-LPEB irradiation hybrid surface treatment. The decrease in extent of crater formation and phase transformation has enabled an improvement in corrosion resistance. The ability of the resolidified layer formed after the hybrid HPDL-LPEB irradiation to form a stable passive film shifts the pitting potential from less than 0 mV/SCE (for untreated 304 SS) to more than +800 mV/SCE, which reduced the depth of corroded pits by 75%. The hybrid HPDL-LPEB irradiation decreased non-metallic inclusions, extent of crater formation and the surface roughness, and improved the pitting corrosion and general corrosion resistance.
关键词： High power diode laser,Pitting corrosion,Electron beam,Microstructure,Corrosion resistance,Stainless steels
更新于2025-09-12 10:27:22
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Narrower Far Field and Higher Efficiency in 1 kW Diode-Laser Bars using Improved Lateral Structuring
摘要： High power, efficient diode-laser bars with narrow far field angles are sought for many applications, for example in the 9xx nm-range for the pumping of Yb:YAG disc and slab lasers. In previous work, broad-area (BA) diode-laser bars with 4 mm resonator length operated with high conversion efficiency η = 62% at operating power Pop = 1 kW in quasi-continuous wave testing (200 μs, 10 Hz), by using low optical loss and low-resistivity vertical structures and high fill-factors (~70%). Lateral far field (95% power) was θ95% > 10°. However, higher η and narrower θ95% are needed for industrial application, and we seek improvements by altering the lateral bar structure for a fixed vertical design (from [1], wavelength λ = 930 nm, loss αi ≈ 0.4 cm-1). First, narrower θ95% at Pop = 1 kW was sought. In previous studies on 90 μm-wide single emitters, deep implantation through the active region was shown to reduce gain at the emitter edges, suppressing higher-order lateral modes, for smaller θ95%, at the price of reduced η and Pop. A similar implantation approach is assessed here in high fill-factor bars, and the drop in η is mitigated by reducing the implantation depth. Second, higher η at Pop = 1 kW was sought, by increasing the fill-factor, for lower electrical resistance.
关键词： lateral structuring,efficiency,narrow far field,high power,diode-laser bars
更新于2025-09-12 10:27:22