Non-conventional laser beam geometries for laser transformation hardening of mild steels

2006 ◽  
Author(s):  
Shakeel Safdar ◽  
Lin Li ◽  
M. A. Sheikh ◽  
Zhu Liu
Keyword(s):  
Laser Beam ◽  
Laser Transformation Hardening ◽  
Conventional Laser

scholarly journals Development of micromirror-based laser line generator

2021 ◽  
Author(s):  
Farzad Hossein Nia
Keyword(s):  
Laser Beam ◽  
System Design ◽  
Laser Line ◽  
Beam Spot ◽  
Optical System Design ◽  
Straight Line ◽  
Laser Module ◽  
Design Software ◽  
Working Distance ◽  
Conventional Laser

A laser line generator projects a straight line on an object and is widely used for alignment, identification, barcode reading, etc. Conventional laser line generators make use of cylindrical and Powell lenses that convert a laser beam spot into a line. Because of a fixed fan angle, however, the length and brightness of the generated line depends on the working distance between the laser module and object. In this project, using the optical system design software Zemax and engineering CAD software Solidworks, a micromirror based laser line generator is designed and fabricated. The performance of the fabricated micromirror based laser line generator is tested and compared with the performance of a conventional laser line generator. The results show that the length and brightness of image line can be kept constant by the designed generator.

Analysis of nonlinear behavior of multimode spatial laser beams with high stability and coherence for medical applications

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Monika Rani ◽  
Natasha Sharma
Keyword(s):  
Laser Beam ◽  
Laser Light ◽  
Nonlinear Behavior ◽  
Single Mode ◽  
Cost Effective ◽  
Laser Beams ◽  
Spectral Brightness ◽  
Weighted Sum ◽  
High Degree ◽  
Conventional Laser

Abstract The laser light is characterized by high degree of directionality, monochromaticity, coherence and spectral brightness. In this manuscript, we have designed and analyzed multimode spatial laser beam. A multimode generator is used to produce four individual polarization modes (LG00, LG22, LG30 and LG31) of laser beam which further converted into thin profiles of individuals and weighted sum of modes. The circular and square aperture effect also make them more stable and coherence as compare to conventional laser beam. Various mode profiles of the beam including single mode and multimode have been shown in results. The combined design of multimode spatial laser beam is simple in construction, cost effective and precise.

EXPERIMENTAL STUDIES ON THE MICROSTRUCTURE AND HARDNESS OF LASER TRANSFORMATION HARDENING OF LOW ALLOY STEEL

2012 ◽  
Vol 36 (3) ◽  
pp. 241-258 ◽  
Author(s):  
Purushothaman Dinesh Babu ◽  
Gengusamynaidu Buvanashekaran ◽  
Karupuudaiyar R. Balasubramanian
Keyword(s):  
Laser Beam ◽  
Laser System ◽  
Experimental Studies ◽  
Surface Hardness ◽  
Base Material ◽  
Optical Microscope ◽  
Laser Hardening ◽  
Beam Power ◽  
Work Piece ◽  
Laser Transformation Hardening

An experimental investigation with Nd:YAG laser system was carried out to study the effects of laser hardening process parameters on the microstructure and hardness during laser hardening of EN25 steel. The laser beam is allowed to scan on the surface of the work piece by varying the laser beam power (750–1250 W) and travel speed (500–1000 mm/min) of the work table. The microstructural features of the laser hardened EN25 steel were analysed using optical microscope. The microstructure of the surface layer was found to consist of plate martensite. A substantial increase in surface hardness was achieved, by a factor of 2 times the base material hardness.

Energy Efficient Laser Beam Welding of Metals with a Ultra-High Brightness Direct-Diode Laser System

2015 ◽  
Vol 805 ◽  
pp. 162-170 ◽  
Author(s):  
Artur Laukart ◽  
Michael Dobler ◽  
Stefanie Kohl ◽  
Haro Fritsche ◽  
Andreas Grohe ◽  
...  
Keyword(s):  
Power Consumption ◽  
Laser Beam ◽  
Numerical Simulations ◽  
Diode Laser ◽  
Laser Beam Welding ◽  
Laser Wavelength ◽  
Efficient Production ◽  
High Brightness ◽  
Laser Systems ◽  
Conventional Laser

The rising level of automation in the automotive industry also involves the use of more and more machines and with that an increase in power consumption. This requires the employment of more efficient production processes with higher efficiency. Laser beam welding offers the opportunity to substitute conventional laser sources like solid state lasers with ultra-high brightness direct-diode laser systems which have the advantage of less power consumption at a comparable beam quality. However, the absorption of laser radiation on metallic surfaces depends on the wavelength, thus the effect of the direct-diode laser wavelength on the welding process has to be investigated. In our research the effect of the laser wavelength on energy efficiency was studied by means of numerical simulations. Furthermore, experimental investigations were carried out to validate the numerical solutions. Different aluminum alloys and steel materials which are used in the automotive environment were investigated within the experiments. Due to the current lack of direct-diode laser systems with a laser power comparable to conventional laser systems, numerical simulations were also used to analyze these future systems. Thus we were able to assess the increase of efficiency in laser beam welding which will be achievable with future high-power direct-diode laser systems.

scholarly journals Development of micromirror-based laser line generator

2021 ◽  
Author(s):  
Farzad Hossein Nia
Keyword(s):  
Laser Beam ◽  
System Design ◽  
Laser Line ◽  
Beam Spot ◽  
Optical System Design ◽  
Straight Line ◽  
Laser Module ◽  
Design Software ◽  
Working Distance ◽  
Conventional Laser

A laser line generator projects a straight line on an object and is widely used for alignment, identification, barcode reading, etc. Conventional laser line generators make use of cylindrical and Powell lenses that convert a laser beam spot into a line. Because of a fixed fan angle, however, the length and brightness of the generated line depends on the working distance between the laser module and object. In this project, using the optical system design software Zemax and engineering CAD software Solidworks, a micromirror based laser line generator is designed and fabricated. The performance of the fabricated micromirror based laser line generator is tested and compared with the performance of a conventional laser line generator. The results show that the length and brightness of image line can be kept constant by the designed generator.

An Analysis of the Effect of Laser Beam Geometry on Laser Transformation Hardening

2005 ◽  
Vol 128 (3) ◽  
pp. 659-667 ◽  
Author(s):  
Shakeel Safdar ◽  
Lin Li ◽  
M. A. Sheikh ◽  
Zhu Liu
Keyword(s):  
Laser Beam ◽  
Laser Scanning ◽  
Rapid Heating ◽  
Homogenization Temperature ◽  
Slow Heating ◽  
Transient Effects ◽  
Full Transformation ◽  
Heating And Cooling ◽  
Beam Geometry ◽  
Laser Transformation Hardening

The effect of transformation hardening depends upon both heating and cooling rates. It is desirable to have a slow heating rate and a rapid cooling rate to achieve full transformation. To date laser transformation hardening has been carried out using circular or rectangular beams which result in rapid heating and cooling. Although the use of different beam intensity distributions within the circular or rectangular laser beams has been studied to improve the process, no other beam geometries have been investigated so far for transformation hardening. This paper presents an investigation into the effects of different laser beam geometries in transformation hardening. Finite element modeling technique has been used to simulate the steady state and transient effects of moving beams in transformation hardening of EN 43A steel. The results are compared with experimental data. The work shows that neither of the two commonly used beams, circular and rectangular, are optimum beam shapes for transformation hardening. The homogenization temperature exceeds the melting point for these beam shapes for the usual laser scanning speeds and power density. Triangular beam geometry has been shown to produce the best thermal history to achieve better transformation and highest hardness due to slower heating without sacrificing the processing rate and hardening depths.

A Three-Dimensional Transient Modeling and Experimental Analysis of Laser Transformation Hardening by Using High Power Direct Diode Laser

2009 ◽  
Author(s):  
S. Santhanakrishnan ◽  
F. R. Kong ◽  
R. Kovacevic
Keyword(s):  
Heat Conduction ◽  
Laser Beam ◽  
Diode Laser ◽  
High Power ◽  
Laser Power ◽  
Continuous Wave ◽  
Three Dimensional ◽  
Material Surface ◽  
Metallic Component ◽  
Laser Transformation Hardening

Laser transformation hardening (LTH) based on rapid heating and cooling cycles produce hard and wear-resistant layers of the metallic component. A high intensity moving laser beam heats up the thin layer of the external surface of the component without damaging the bulk of material. The metallurgical transformations taking place in the material during the thermo-kinetic cycles could effectively improve the mechanical properties of its surface. Nowadays, a high power direct diode laser (HPDDL) has been accepted by industry as a valuable tool to carry out this process. A three-dimensional (3-D) transient thermo-kinetic model has been developed to predict the temperature profile of the hardened layers of the material surface. The temperature-dependence of the thermal properties of the material is taken into account in the model. The laser beam is considered as a moving line heat source with a uniform distribution of laser power. The numerical solution is obtained by using a transient 3-D heat conduction equation with convection boundary conditions at the surfaces of the workpiece. A number of experiments have been carried out to harden components of AISI S7 tool steel by a continuous wave (CW) HPDDL at different power levels (1200 W – 2000 W) and different scanning speeds (5 mm/s – 20 mm/s). The main processing parameters such as laser power and scanning speed are optimized based on the numerical analysis of the heat conduction involved in this process. The numerical simulation results are compared with results produced experimentally by a HPDDL laser operating in CW, showing good agreement.

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