Papers by Keyword: Laser Forming

Abstract: 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.

Abstract: Laser forming, an advanced technology widely used for the shaping and adjustment of metallic and non-metallic materials, can also be used to process metal/ceramic materials. Laser forming technique is based on the temperature gradient mechanism (TGM) and temperature distribution is the main factor that affects the laser forming process. In this study, the finite element method (FEM) has been applied to predict the temperature field of TC4/SiC metal/ceramic bilayer during the laser forming process. Temperature of different points in the upper surface of the metal material, interface with the two layers and the lower surface of the ceramic material has been calculated. Parameters like laser input power and laser scan-speed have been investigated. This study is aimed at providing data for the precise control of laser forming in the process of shaping and adjusting TC4/SiC bilayers.

Abstract: A process design tool is proposed for parametric optimization of laser forming based on integrated Finite Element Method, Response Surface Method and grey Relation analysis. A sequentially integrated FEM-RSM-GRA framework has been developed and implemented to determine the optimum parameters for maximum bend angle, minimum heat affected zone (HAZ) and minimum residual stress. Four process parameters namely power, scanning velocity,spot diameter and sheet thickness had been consideredhave been optimized to minimize the distortion of the structure. The optimization results revealed the effectiveness of the methodology for process design of laser forming of AISI stainless steel sheet with reduced haz and residual stress.

Abstract: In recent years, the recycling of resources has become important because of the aggravation of global environmental concerns. In light of this, it is necessary to minimize the resource needs of current production systems. This concept is called sustainable development. When this concept is applied to machine tools, the assumption is that small parts should be processed using small machines. Additionally, the diversification of consumer needs and the ephemeralization of product life cycles are progressing in industry. As a result, the overall production system has changed from high-mix low-volume production manufacturing, to variant types in variable quantity. In this background, the cell production system is receiving attention as a production system that can achieve variant types in variable quantity. The cell production system also requires miniaturization and process consolidation of machine tools, which has given rise to the need to consolidate heat treatments, especially as part of the process consolidation of machine tools. Laser beams have proved to be effective heat sources when integrated into heat-treatment processes, such as quenching and tempering on machine tool tables. On the other hand, In the case of the thin plate, it is well known that the deformation of a plate occurs due to laser irradiation, as named a laser forming. The laser forming is also effective to generate the complex shape without a press die set. Thus, we propose that the hybrid process of laser heat treatment and forming of thin plate with a small power semiconductor laser, and demonstrate that the proposed method makes it feasible to generate the hardened sheet metal products with a compact machine tools. Moreover, considering the power consumption in laser quenching and forming process, we investigate an appropriate laser irradiation condition from a view of reducing the environmental burden.

Abstract: Laser forming is a technology which can form sheet material such as steel and plastic by irradiating a laser beam on the surfaces of material. In the forming, it does not need costly dies and molds, and forming degrees of freedom are high. However, since the forming mechanisms are complex, complete forming technology for practical use has not been developed. The objectives of this paper are to explain phenomena of laser forming by experiments and FEM analysis and to develop a forming method of curved surfaces by laser forming. The phenomena are explained by the temperature change, stress change, and plastic strain change at a laser irradiation point which was obtained by FEM analysis. Line energy is proposed for explanation of laser forming phenomena to classify the forming mechanisms, and a method is proposed in order to form curved surfaces of sheet material by irradiating a laser beam on maximum and minimum curvature lines. The effectiveness of the method was verified by a basic experiment.

Abstract: Nowadays, resource saving technologies have become important because of increasing global environmental problems. Moreover, demand is increasing for the manufacturing and machining of small mechanical parts because of the downsizing of electronic mobile devices. Thus, one requirement has emerged that these small parts have to be fabricated by smaller machine tools to reduce the environmental burden. Here, when we look at the heat treatment process, it is found that most small parts are generally treated with a large size furnace as well. Therefore, we focus on compact machine tools to develop the clean and energy-saving technology in the manufacturing fields. In the present report, we consider an in-situ laser heat treatment technology integrated on the table used for compact machine tools. In particular, we perform the entire laser hardening of a small thin plate with a small power semiconductor laser, which is an attempt to harden a whole steel sheet. However, thin plates deform during the laser hardening process, which is called “laser forming.” Thus, we discuss an effective irradiation path to prevent the deformation of plates while quenching the entire plate. Moreover, considering the power consumption in the laser quenching process, we investigate an appropriate laser irradiation condition.

Abstract: Laser forming ofopen-cell aluminum foams can be modeled by means of 3D thermo-mechanical models but the correct evaluation of the alloy material properties is a key-factor for obtaining good predictions. In order to increase the model predictability from a quantitative point of view, further information about the material behavior under laser exposure is necessary. In this study the effect of the temperature on the mechanical properties of a commercial aluminum sponge has been evaluated in terms of yielding stress and tangent modulus. Experimental tests have been performed by compression and used to infer mechanical properties by means of a 3D FE model. The same approach has been used also to evaluate the effect of a heat treatment of the sponge on the material behavior during forming. In conclusion numerical simulation of laser heating has been used to show the effect of the laser-material interaction on the final homogeneity of processed foams.

Abstract: Laser forming is an advanced process in sheet metal forming in which a laser heat source is used to shape the metal sheet. This is a new manufacturing technique that forms the metal sheet only by thermal stress. Analyses of the temperature and stress fields are very important to identify the deformation mechanism in laser forming. In this experiment, the relationship between laser irradiation position and the bending angle, in terms of laser forming, has been tested and the result was compared and analyzed with respect to the theoretical bending moment and the elastic curve differential equation.

Abstract: Laser forming of open-cell aluminum foams has been modeled by means of a 3D finite element model which is able to take into account the real foam geometry as well as the main process variables. A parametric procedure has been defined for the geometry construction and meshing, and the simulation run. In order to calibrate and validate numerical modeling, compression and flexure tests were performed on a closed-cell aluminum foam. The simulation of mechanical tests allowed a correct modeling of the aluminum alloy behavior under plastic deformation. The same material behavior was implemented in a complex thermo-mechanical model for laser bending simulation. The final model is able to predict the shape evolution during forming and the correlation between process variables and final bent angles.

Abstract: Laser forming (LF) is a non-contact method to shape metallic sheets and tubes by induced thermal stress without melting using a de-focused laser beam. Laser forming offers the industrial promise of controlled shaping of metallic and non-metallic components for prototyping, correction of design shape or distortion and precision adjustment applications. In order to fulfil this promise in a manufacturing environment the process must have a high degree of control, be repeatable and have a minimal impact on the material and mechanical properties of the part to be formed. In order to demonstrate the capability of the LF process a study is presented in this paper on the 3D Laser Forming of ERW steel square tubes SHS EN10305-5 E220 +CR2 (1.5x25x25mm and 1.5x50x50mm 300mm long tube) using a 1.5kW CO₂ laser and industrial 5 axis gantry. Strategies have been developed for out of plane bending with specific emphasis on process throughput balanced with minimising adverse localised changes to material properties that could lead to stress concentration features in a component in service. Presented in this paper is empirical 3D LF shape data verified by a scanning laser profiler, a metallurgical study, hardness testing and a FEM model developed in Comsol Multi-Physics. The results of these studies were employed to develop optimised scan strategies for the controlled laser forming of the ERW steel square tubes within strict metallurgical constraints.