scholarly journals Effects of Forced Cooling In Laser Forming

2019 ◽  
Vol 8 (10) ◽  
pp. 3782-3787
Keyword(s):  
Numerical Model ◽  
Research Work ◽  
Three Dimensional ◽  
Weight Ratio ◽  
Laser Forming ◽  
Beam Diameter ◽  
Forming Process ◽  
Scanning Velocity ◽  
Cooling Conditions ◽  
Forced Cooling

This paper presents the numerical bending studies of the alloy sheet of Magnesium M1A to achieve the bigger bending angle in a single laser forming process. A three-dimensional model of finite elements was created and different simulations were performed for sheet laser bending. Magnesium alloys are difficult-to-form yet have huge applications in automobile and aerospace industries because of its high strength to weight ratio. To study the sheet bending method and effect of various process parameters including laser scanning velocity, beam diameter and laser power, a three-dimensional numerical model was developed. The developed numerical model was designed with ABAQUS Simulia and validated with the published numerical model. On the validated numerical model, a further number of simulations were performed to understand the effects of forced cooling conditions in single scan laser forming process. This research work concluded that forced cooling conditions in laser forming can be used to increase the bend angle in a single scan.

Numerical and experimental analysis on cold-forming and spring-back of hull plate

2018 ◽  
Vol 233 (3) ◽  
pp. 561-569 ◽  
Author(s):  
Wei Shen ◽  
Renjun Yan ◽  
Shuangying Li
Keyword(s):  
Three Dimensional ◽  
Dimensional Accuracy ◽  
Ship Hull ◽  
Laser Forming ◽  
Successive Approximation Method ◽  
Spring Back ◽  
Forming Process ◽  
Cold Forming ◽  
Thick Plates ◽  
Forming Mechanism

Ship hull structures are fabricated by curved thick plates before they are welded together. There are traditional methods such as, line heating and laser-forming methods for plate bending. However, it is recognized that the hot-forming technology causes a series of troubles on doubly or multiple curved plates. Multi-point forming mechanism with square press heads is a new forming process for three-dimensional ship hull plate. Cold-forming has a high dimensional accuracy but results in spring-back. The spring-back process of curved thick plates in the finite element method is analyzed and the predicted results are compared with the test results in the present paper. To ensure the forming precision, the successive approximation method is also developed and verified to control the spring-back.

Prediction and Optimization of Deformations in Coupling Mechanism Based Laser Forming of Sheet Metals

2019 ◽  
Vol 969 ◽  
pp. 552-557
Author(s):  
Kuntal Maji
Keyword(s):  
Process Parameters ◽  
Metal Forming ◽  
Three Dimensional ◽  
Laser Forming ◽  
Coupling Mechanism ◽  
Sheet Metals ◽  
Forming Process ◽  
Out Of Plane ◽  
Metal Forming Process ◽  
Plane Deformations

Fabricating three dimensional shaped surfaces from flat sheet metals by laser forming, both out-of-plane and in-plane deformations are required. This article presents the modeling of coupling mechanism activated laser forming of sheet metals based on experimental data for prediction and optimization of bending and thickening deformations. Experiments were performed based on a central composite design of experiments on coupling mechanism based laser metal forming process considering the input process parameters like laser power, scan speed and spot diameter, bending and thickening were taken as the outputs. Neural network and neuro-fuzzy system-based models were developed to carry out both forward and inverse modeling of the laser metal forming process under the coupling mechanism. Multi-objective optimization based on the non-dominated sorting genetic algorithm was used to obtain multiple optimal solutions to achieve different amounts of out-of-plane and in-plane deformations. The proposed method could guide for a suitable selection of the process parameters to produce three-dimensional shapes utilizing coupling mechanism-based laser forming using multiple laser line heating.

A Numerical and Experimental Study of Sheet Metal Bending by Pulsed Nd:Yag Laser with DOE Method

2009 ◽  
Vol 83-86 ◽  
pp. 1076-1083 ◽  
Author(s):  
M. Hosseinpour Gollo ◽  
Hassan Moslemi Naeini ◽  
G.H. Liaghat ◽  
S. Jelvani ◽  
M.J. Torkamany
Keyword(s):  
Experimental Study ◽  
Sheet Metal ◽  
Nd:Yag Laser ◽  
Metal Forming ◽  
Flexible Manufacturing ◽  
Three Dimensional ◽  
Laser Source ◽  
Laser Forming ◽  
Beam Diameter ◽  
Doubly Curved

Metal forming by a laser source is an efficient and economical method for forming sheet metal into straight bend and doubly curved shape. It can be most useful in the automation of sheet metal forming. This paper presents an FEM model for three dimensional thermo-mechanical simulation of the laser forming. The aim of this simulation and experimental study is to identify the response related to deformation and characterize the effects of process parameters such as laser power, beam diameter, scans velocity and pulse duration, in terms of bending angle for a square sheet part. Extensive experimentation, including a design of experiments, is performed to address the above-mentioned aims. From these experiments it has been determined that laser forming using Nd:YAG laser is a flexible manufacturing process for steel sheet bending.

Three-Dimensional Numerical Simulation and Experimental Study of Sheet Metal Bending by Laser Peen Forming

2010 ◽  
Vol 132 (6) ◽  
Author(s):  
Yongxiang Hu ◽  
Yefei Han ◽  
Zhenqiang Yao ◽  
Jun Hu
Keyword(s):  
Numerical Model ◽  
Sheet Metal ◽  
Laser Energy ◽  
Three Dimensional ◽  
Target Surface ◽  
Thick Sheet ◽  
Specimen Thickness ◽  
Forming Process ◽  
Form Complex ◽  
Peen Forming

Laser peen forming (LPF) is a purely mechanical forming method achieved through the use of laser energy to form complex shapes or to modify curvatures. It is flexible and independent of tool inaccuracies that result from wear and deflection. Its nonthermal process makes it possible to form without material degradation or even improve them by inducing compressive stress over the target surface. In the present study, a fully three-dimensional numerical model is developed to simulate the forming process of laser peen forming. The simulation procedure is composed of several steps mainly including the shock pressure prediction, the modal analysis, and the forming process calculation. System critical damping is introduced to prevent unnecessary long post-shock residual oscillations and to greatly decrease the solution time for simulation. The bending profiles and angles with different thicknesses are experimentally measured at different scanning lines and scanning velocities to understand the process and validate the numerical model. The calculated bending profiles and angles agree well with the trend of the measured results. But it is found that simulations with the Johnson–Cook model are more consistent, matching the experimental results for the thick sheet metal with a convex bending, while the elastic-perfectly-plastic model produces a better agreement even though with underestimated values for the thinner sheet metal with a concave bending. The reason for this phenomenon is discussed, combining the effects of strain rate and feature size. Both the simulation and the experiments show that a continuous decrease in bending angle from concave to convex is observed with increasing specimen thickness in general. Large bending distortion is easier to induce by generating a concave curvature with LPF, and the angle of bending distortion depends on the number of laser shocks.

scholarly journals Effects of Laser Beam Parameters on Bendability and Microstructure of Stainless Steel in Three-Dimensional Laser Forming

2019 ◽  
Vol 9 (20) ◽  
pp. 4463 ◽  
Author(s):  
Daniyal Abolhasani ◽  
Seyed Mohammad Hossein Seyedkashi ◽  
Mohammad Hoseinpour Gollo ◽  
Young Hoon Moon
Keyword(s):  
Stainless Steel ◽  
Three Dimensional ◽  
Laser Forming ◽  
Strengthening Effect ◽  
Beam Diameter ◽  
Equiaxed Dendrite ◽  
Aisi 316 Stainless Steel ◽  
Aisi 316 ◽  
Beam Parameters ◽  
Hatch Spacing

In this study, the effects of beam diameter and hatch spacing between the scanning paths on the bendability and microstructural behavior of an AISI 316 stainless-steel sheet in three-dimensional laser forming were investigated. The strain on the heating lines and that between the scanning tracks were numerically investigated to elucidate the effects of process parameters. The strain on heating lines and that between scanning tracks were numerically investigated. The increase in hatch spacing caused a larger amount of counter bending to be retained in the unaffected areas between the tracks through a process dominated by a temperature gradient mechanism (TGM), and also caused a lower deformation. The formation of small equiaxed dendrite grains instead of coarse and inhomogeneous austenite grains occurred during the process at a larger beam diameter and smaller hatch spacing, which increased the bendability of the material, owing to the decrease in anisotropy in the microstructure. Moreover, the increase in the grain size of the reheated overlap region of the deformed sample led to a higher bendability. Under these conditions, the microhardness was also increased owing to the grain boundary strengthening effect.

Process Optimization of Laser Micro-Bending Using iSIGHT

2008 ◽  
Vol 575-578 ◽  
pp. 408-415
Author(s):  
Jie Liu ◽  
Yan Jin Guan ◽  
Sheng Sun ◽  
Guang Chun Wang
Keyword(s):  
Finite Element ◽  
Stainless Steel ◽  
Laser Power ◽  
Geometrical Parameters ◽  
Beam Diameter ◽  
Forming Process ◽  
Bending Angle ◽  
Scanning Velocity ◽  
Stainless Steel Foil ◽  
Bending Process

There are many factors, such as the laser and geometrical parameters, which influence greatly on the laser bending process. So it is of great importance to determine these variables properly. Considering the relationship of material properties and temperature, a 3-D thermal-mechanical finite element analysis model for laser micro-bending of stainless steel foil is developed based on the software MSC.Marc, and the laser micro-bending process of 0.1mm thick stainless steel foil is implemented. The finite element method simulation process is integrated with the optimization software package iSIGHT through secondary development. The objective function is to realize the maximum bending angle after single laser scan, and laser power, beam diameter and scanning velocity are regarded as the design variables. The forming process is optimized by using genetic algorithm. The optimal result shows the bending angle can be got to the maximum 1.0332°when the laser power, beam diameter and scanning velocity are 32W, 0.17mm and 132mm/s respectively. The experiment results are in good agreement with optimal results.

Numerical and Experimental Analysis for Large Radius Deformation of Stainless Steels by Laser Forming Process

2005 ◽  
Author(s):  
J. Pennuto ◽  
J. Choi
Keyword(s):  
Experimental Data ◽  
Phase Transformation ◽  
Experimental Testing ◽  
Three Dimensional ◽  
Laser Forming ◽  
Bend Angle ◽  
Large Radius ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Forming Process

In an effort to develop a process free of dedicated tooling, this research seeks to study large radius deformation by laser forming. Experimental testing was conducted to determine how the laser parameters affect the single pass output bend angle as well as the additive bend angle from successive parallel, evenly spaced laser irradiations. As an extension of the previous developments, this work seeks to develop a three-dimensional model to simulate the multi-scan laser process. It is of interest to determine how sophisticated a three-dimensional case is required for sufficient agreement to experimental data. The simulated results of bending angle are compared with experimental data and suggestions for future study include the implementation of phase transformation and microstructure data within the model to account for stress development resulting from phase transformation and grain growth.

Experimental and 3D Finite Element Studies of CW Laser Forming of Thin Stainless Steel Sheets

2000 ◽  
Vol 123 (1) ◽  
pp. 66-73 ◽  
Author(s):  
Guofei Chen ◽  
Xianfan Xu
Keyword(s):  
Finite Element ◽  
Stainless Steel ◽  
Laser Scanning ◽  
Continuous Wave ◽  
Laser Forming ◽  
Beam Diameter ◽  
Element Analysis ◽  
Scanning Velocity ◽  
3D Finite Element ◽  
Steel Sheets

Laser forming as a springback-free and noncontact forming technique has been under active investigation over the last decade. Previous investigations are mainly focused on forming of large and thick workpieces using high power lasers, with less work on precision, micro-scale bending of small and thin sheets. In this work, a 4 W continuous wave argon ion laser is used as the energy source, and the laser beam is focused to a beam diameter of tens of micrometers to induce bending of thin stainless steel sheets. When the laser scanning velocity is above 8 mm/s, bending can be explained by the temperature gradient mechanism, while decreasing the scanning velocity leads to the buckling mechanism of bending. The bending angle is measured at various processing conditions. A fully 3D finite element analysis is performed to simulate the thermo-elasto-plastic deformation process during laser forming. Experimental measurements and computational results agree in trend, and reasons for the deviation are discussed.

Modeling and optimization of laser bending parameters via response surface methodology

2012 ◽  
Vol 227 (7) ◽  
pp. 1577-1584 ◽  
Author(s):  
Esmaeil Ghadiri Zahrani ◽  
Abdolali Marasi
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Sheet Thickness ◽  
Free Edge ◽  
Simultaneous Optimization ◽  
Laser Forming ◽  
Beam Diameter ◽  
Forming Process ◽  
Bending Angle ◽  
Modeling And Optimization

The existence of various variables in the laser forming process brings about the implementation of two important issues of modeling and optimization to more precisely predict bending angle so as to achieve desirable conditions. In this paper, the effect of independent process parameters such as laser power, beam diameter, scan speed, sheet thickness and also the heating position on the resulted bending angle from the sheet free edge was investigated through experimentation. The results indicate different influence of parameters on the angle. Also, using response surface methodology and after conducting analysis of variance, an efficient second-order mathematical model was fit to bending angle. Consequently, with the aim of making bending angle robust in relation to possible parametric fluctuations in the process, a simultaneous optimization was carried out by use of propagation of error approach and optimal parametric combination to reach the maximum value of the angle.

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