Papers by Keyword: Fiber Laser

Abstract: Steel alloys made of sheet metal are important materials because of their high strength applications in construction, automobiles, ships, aircraft, and military products. Among the best and fastest non-traditional ways to cut sheet metal these days is laser cutting. Therefore, it's important to comprehend how the parameters of LC affect the quality of the cut. A thorough analysis was provided to find out which LC parameters have the greatest impact on cutting quality as well as how they affect the kerf quality and cut surface. An overview of the benefits of LC over other machining techniques was provided. Furthermore, an explanation of the various laser sources and the laser cutting technique were given. by eliminating each source's spectrum of cut material thicknesses and their benefits. Graphs and formulae provided a detailed illustration of the cutting performance characteristics. Tables and graphs that display the whole classification of the examined papers were used to utilized to arrange the discussion and analysis of the research into such a detailed discussions. It was discovered that Steel alloys are the most commonly used for laser cutting (59%), followed by aluminum alloys (13%) and titanium alloys (12%). While other subjects constitute 16% of research in this field It was also found that The most common parameters utilized as controls are cutting speed (30%), Laser power (23%), Assist gas pressure (21%), Pulse frequency (9%) and Focal position (7%), in general the ideal parameters to achieve low (SR), small (HAZ) width, small (KW) and small (KT) are low (Pu), high (V), medium (P), high (SOD), medium (PF), medium (PW), small (ND), small (T), and N2 as an assist gas.

Abstract: The article presents the results of studying the magnetic materials obtained via fusing metallic powder with laser radiation in static magnetic field. The powder to be fused was prepared with milling the alloy containing rare-earth and transition metals. Austenitic stainless steel was used as a substrate material for obtaining samples. The structure of the magnets obtained was studied by means of SEM. EDS was used to estimate the distribution of elements in the samples. The study of magnetic properties showed the decrease of residual magnetization and coercivity in the magnets obtained with laser fusing as compared to raw material.

Abstract: The work addresses the possible use of a third-generation robotic complex with a fiber laser to restore and strengthen the working parts of the stamping rig in the conditions of a large engineering company. The method of restoring and fine-hardening of stamps from complex steels 5X2MNF, 4X5MFS with solid-state laser is justified. Economic analysis was carried out and the economic effect of the complex was described.

Abstract: AA2219 is a superior performance Al-base alloy which promises toughness, strength and creep resistance which allows the deposition of titanium nitride (TiN) coating at 200 °C. The present research addresses the issue of poor wear properties of the alloy, using state of the art technologies, to deposit hard and adherent thin TiN layer followed by laser surface texturing. The thickness of sub-micron size coating is determined by appropriate modification of the existing mathematical model and composite microhardness values. Laser energy density of 20.8 J/cm² and 4 repeated pulses is optimized to produce regular size and shape of micro-holes on TiN-coated samples. Epoxy-based MoS₂ lubricant is deposited on laser textured samples to produce ultra-low friction surfaces. The micro-holes act as a micro-reservoir of MoS₂ solid lubricant. Field emission scanning electron microscope and optical profilometer were used to estimate the topology, shape, size, and depth of micro-holes. The cross-sectional view shows the successful impregnation of epoxy-based MoS₂ due to the chemisorption of functional groups with an Al oxide surface.

Abstract: In this paper we investigate the fiber Bragg grating (FBG) arrays selectively inscribed in a multicore fiber for a different sensor and laser applications. Particularly, wavelength-switchable and tunable fiber laser was realized based on uniform and non-uniform FBGs precisely positioned in the selected cores. A quasi-distributed 3D shape sensor based on FBG array inscribed in a multicore fiber with helically twisted side cores was fabricated and applied for shape reconstruction of papillotome.

Abstract: This paper investigates the effect of fiber laser surface modification of AISI 316L austenitic stainless steel on corrosion behavior. In the experiments, the fiber laser with center wavelength of 1062 nm was employed with various laser parameters of beam velocity and laser frequency. The laser-treated has performed on the specimen surface in order to form the melted layer with an argon gas shielding. The electrochemical tested results showed that the laser-treated increases 40% pitting potential. Moreover, the results also exhibited corrosion potential shift to more positive potential. On the basis of the findings on the corrosion improvement, it can be concluded that the pitting potential of the material can be improved by a corrosion protective layer from the new laser-treated surface.

Abstract: In order to fabricate the micro cavity with complex structure on stainless steel, the technology of micro electrochemical machining based on surface modification by fiber laser is adopted. Heating scan on the surface of 304 stainless steel by using fiber laser can realize marking. In the process of laser heating and metal melting on the surface of 304 stainless steel, oxide layer can be formed and phase transformation can also occur, and the corrosion resistance layer with predefined pattern is formed. In the next process of micro electrochemical machining, the laser masking layer severs as the protective layer to realize micro machining of micro cavity. A newly developed device of electrochemical micro machining based on surface modification by fiber laser can meet the micro machining requirement. After laser masking processing through laser scanning on the surface of the 304 stainless steel, the passivation electrolyte and high-frequence-pulse electrochemical machining power supply were adopted, and the samples with typical structures by using electrochemical micromachining with fiber laser masking were fabricated.

Abstract: Paper deals with the welding of AISI 304 thin sheets with the thickness of 1 mm by fiber laser. Statistical software MiniTab was used for planning the experiment. The influence of laser power, welding speed and focal point position on width and depth of weld bead was examined. Output power, welding speed and focus point position were used as variable factors for DOE. Samples were prepared by standard metallography. Weld bead width and depth were evaluated. Statistical results were afterward verified by welding reference samples with material the thickness of 0.25 mm. The difference between real width of weld bead and predicted width obtained from statistical software was 8.26 %. In case of weld depth measurement, the difference was 23 %.

Abstract: Emission spectra of Sn, Sb, Pb and Bi doped silica glasses co-doped with Al and P prepared by modified chemical vapor-phase deposition (MCVD) using solution doping technique are presented. Bi doped silica glasses present emission/excitation (Em/Ex) bands around 470/(330, 220nm) 600/(470, 350, 270nm), 730 and 830/(820, 420, 380, 250nm), with the intensity ratio of these bands depends on the composition, indicating that different emission sources (valence states or defects) are present together. The Em/Ex of Sb doped silica glasses also depend on composition, and are similar of Bi doped silica glasses. The lifetime at 830 and 1400 in Bi or Sb doped silica glasses are similar and around 60 and 850μs, respectively. The lifetime around 600nm was 3.2 and 11μs, respectively to Bi and Sb doped silica glasses. The Sn doped silica glass present Em/Ex bands around 305/265nm, 400/(270, 340nm) and 430/280nm. The Pb doped silica glass present Em/Ex around 370/290nm and 540/320nm. No significant change in the emission bands in the visible range are observed when the Sn or Pb doped silica glass are co-doped with Al or P. The present results of Em/Ex suggest that Bi and Sb can be candidate for fiber lasing in visible range (around 600nm) using the available LD pumping (ex: 405nm). Despite Sn and Pb doping shows strong emission around 400nm, unfortunately until now there is no LD that can be used as pumping source.

Abstract: Dissimilar aluminum alloys, AA2024-0 and AA7075-T6 were laser welded on both sides in a T-joint configuration using a low power fiber laser. The effect of welding speed (9, 12, 15, 18 and 21 mm/s) on weldability was evaluated at laser power of 270W with argon gas as the shielding gas. The sample welding angle was fixed at 45^° with an interval of 180 seconds between each welding pass. Macrograph observations revealed that full penetration with pore free weld of these dissimilar joint was obtained at the laser parameters of 270 W and 9 mm/s, suggesting that lower welding speed is preferred during low power laser welding.