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Y. Lawrence Yao - One of the best experts on this subject based on the ideXlab platform.
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Laser Forming of sandwich panels with metal foam cores
Journal of Laser Applications, 2019Co-Authors: Tizian Bucher, Steven Cardenas, Ravi Verma, Y. Lawrence YaoAbstract:Over the past decade, Laser Forming has been effectively used to bend various metal foams, opening the possibility of applying these unique materials in new engineering applications. The purpose of the study was to extend Laser Forming to bend sandwich panels consisting of metallic facesheets joined to a metal foam core. Metal foam sandwich panels combine the excellent shock-absorption properties and low weight of metal foam with the wear resistance and strength of metallic facesheets, making them desirable for many applications in fields such as aerospace, the automotive industry, and solar power plants. To better understand the bending behavior of metal foam sandwich panels, as well as the impact of Laser Forming on the material properties, the fundamental mechanisms that govern bending deformation during Laser Forming were analyzed. It was found that the well-established bending mechanisms that separately govern solid metal and metal foam Laser Forming still apply to sandwich panel Laser Forming. However, two mechanisms operate in tandem, and a separate mechanism is responsible for the deformation of the solid facesheet and the foam core. From the bending mechanism analysis, it was concluded on the maximum achievable bending angle and the overall efficiency of the Laser Forming process at different process conditions. Throughout the analysis, experimental results were complemented by numerical simulations that were obtained using two finite element models that followed different geometrical approaches.Over the past decade, Laser Forming has been effectively used to bend various metal foams, opening the possibility of applying these unique materials in new engineering applications. The purpose of the study was to extend Laser Forming to bend sandwich panels consisting of metallic facesheets joined to a metal foam core. Metal foam sandwich panels combine the excellent shock-absorption properties and low weight of metal foam with the wear resistance and strength of metallic facesheets, making them desirable for many applications in fields such as aerospace, the automotive industry, and solar power plants. To better understand the bending behavior of metal foam sandwich panels, as well as the impact of Laser Forming on the material properties, the fundamental mechanisms that govern bending deformation during Laser Forming were analyzed. It was found that the well-established bending mechanisms that separately govern solid metal and metal foam Laser Forming still apply to sandwich panel Laser Forming. Howev...
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Laser Forming of Sandwich Panels With Metal Foam Cores
Journal of Manufacturing Science and Engineering-transactions of The Asme, 2018Co-Authors: Tizian Bucher, Steven Cardenas, Ravi Verma, Y. Lawrence YaoAbstract:Over the past decade, Laser Forming has been effectively used to bend various metal foams, opening the possibility of applying these unique materials in new engineering applications. The purpose of the study was to extend Laser Forming to bend sandwich panels consisting of metallic facesheets joined to a metal foam core. Metal foam sandwich panels combine the excellent shock-absorption properties and low weight of metal foam with the wear resistance and strength of metallic facesheets, making them desirable for many applications in fields such as aerospace, the automotive industry, and solar power plants. To better understand the bending behavior of metal foam sandwich panels, as well as the impact of Laser Forming on the material properties, the fundamental mechanisms that govern bending deformation during Laser Forming were analyzed. It was found that the well-established bending mechanisms that separately govern solid metal and metal foam Laser Forming still apply to sandwich panel Laser Forming. However, two mechanisms operate in tandem, and a separate mechanism is responsible for the deformation of the solid facesheet and the foam core. From the bending mechanism analysis, it was concluded on the maximum achievable bending angle and the overall efficiency of the Laser Forming process at different process conditions. Throughout the analysis, experimental results were complemented by numerical simulations that were obtained using two finite element models that followed different geometrical approaches.
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Advances in Laser Forming of metal foam: mechanism, prediction and comparison
International Journal of Mechatronics and Manufacturing Systems, 2018Co-Authors: Tizian Bucher, Y. Lawrence YaoAbstract:Laser Forming is a well-studied process that has successfully been used to form sheet metal. More recently, attempts have been made to use Laser Forming to bend metal foams. While several studies reported that Forming of metal foams is possible, it was found that the process window is fundamentally different, and many well-established concepts from sheet metal Laser Forming do not apply or require modification. This paper reviews the advances in metal foam Laser Forming and compares the acquired knowledge with the well-established knowledge of sheet metal Laser Forming. Differences in the bending mechanism are discussed, and the process windows are analysed in detail. Additionally, key differences in the numerical approaches are discussed, namely the impact of the model geometry and the incorporation of density-dependent material data. Finally, subjects requiring further investigation are reviewed.
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Bending Mechanism Analysis for Laser Forming of Metal Foam
Volume 1: Processes, 2017Co-Authors: Tizian Bucher, Adelaide Young, Chang Jun Chen, Min Zhang, Y. Lawrence YaoAbstract:To date, the industrial production of metal foam components has remained challenging, since few methods exist to manufacture metal foam into the shapes required in engineering applications. Laser Forming is currently the only method with a high geometrical flexibility that is able to shape arbitrarily sized parts. What prevents the industrial implementation of the method, however, is that no detailed experimental analysis has been done of the metal foam strain response during Laser Forming, and hence the existing numerical models have been insufficiently validated. Moreover, current understanding of the Laser Forming process is poor, and it has been assumed, without experimental proof, that the temperature gradient mechanism (TGM) from sheet metal Forming is the governing mechanism for metal foam. In this study, these issues were addressed by using digital image correlation (DIC) to obtain in-process and post-process strain data that was then used to validate a numerical model. Additionally, metal foam Laser Forming was compared with metal foam 4-point bending and sheet metal Laser Forming to explain why metal foam can be bent despite its high bending stiffness, and to evaluate whether TGM is valid for metal foam. The strain measurements revealed that tensile stretching is only a small contributor to foam bending, with the major contributor being compression-induced shortening. Unlike in sheet metal Laser Forming, this shortening is achieved through cell wall bending, as opposed to plastic compressive strains. Based on this important difference with traditional TGM, a modified temperature gradient mechanism (MTGM) was proposed.
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Experimental and numerical investigation of Laser Forming of closed-cell aluminum foam
International Congress on Applications of Lasers & Electro-Optics, 2014Co-Authors: Min Zhang, Chang Jun Chen, Grant Brandal, Dakai Bian, Y. Lawrence YaoAbstract:Aluminum foams are generally attractive because of their ability of combining different properties such as strength, light weight, thermal and acoustic insulation. These materials, however, are typically brittle under mechanical loading and this severely limits their use. Recent studies have shown that Laser Forming is an effective way to shape foam panels . In this paper, the Laser Forming of Al-Si closed-cell foam was investigated through experiments and numerical simulations.Bending angle as a function of the number of passes at different Laser power and scan velocity values was obtained for large- and small-pore foams. In the finite element analysis, both effective-property and cellular models were considered for the closed-cell foam. Multi-scan Laser Forming was also simulated to study the accumulative effect on the final bending angle. Results confirmed that temperature gradient mechanism (TGM) was dominant during Laser Forming of the closed-cell Al-Si foam material under the conditions considered. This paper further discussed the reasonableness and applicability of the two models. The effective-property model predictions generally agree with experimental results of multi-scan Laser Forming. The cellular model somewhat underestimates the temperature gradients in the thickness direction but significantly overestimates the stress level likely due to the fact that the non-homogeneity in pore shape, size and distribution was inadequately accounted for.Aluminum foams are generally attractive because of their ability of combining different properties such as strength, light weight, thermal and acoustic insulation. These materials, however, are typically brittle under mechanical loading and this severely limits their use. Recent studies have shown that Laser Forming is an effective way to shape foam panels . In this paper, the Laser Forming of Al-Si closed-cell foam was investigated through experiments and numerical simulations.Bending angle as a function of the number of passes at different Laser power and scan velocity values was obtained for large- and small-pore foams. In the finite element analysis, both effective-property and cellular models were considered for the closed-cell foam. Multi-scan Laser Forming was also simulated to study the accumulative effect on the final bending angle. Results confirmed that temperature gradient mechanism (TGM) was dominant during Laser Forming of the closed-cell Al-Si foam material under the conditions considered. ...
Hong Shen - One of the best experts on this subject based on the ideXlab platform.
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Mixed-dimensional coupling modeling for Laser Forming process
Proceedings of the Institution of Mechanical Engineers Part C: Journal of Mechanical Engineering Science, 2014Co-Authors: Hong Shen, Zhenqiang YaoAbstract:Efficient Laser Forming modeling for industrial application is still in the developing stage and many researchers are in the process of modifying it. Conventional three-dimensional finite element models are still expensive on computational time. In this paper, a finite element model adopting a shell-solid coupling technique is developed for the thermomechanical analysis of Laser Forming process. In the shell-solid coupling method, an additional shell element plane is utilized to transfer heat flux and displacement from the solid elements to the shell elements. The effects of the additional interface shell element thickness on temperature distribution and final distortion are investigated. The presented shell-solid coupling method is evaluated by the results of three-dimensional simulations and experimental data.
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modelling of Laser Forming an review
Computational Materials Science, 2009Co-Authors: Hong Shen, Frank VollertsenAbstract:Abstract Laser Forming is achieved by plastic deformation induced by thermal stresses resulting from rapid nonlinear thermal cycles. Unlike mechanical Forming, the process requires no hard tooling or external forces and thus there is no spring-back effect. A number of mechanisms have been identified to explain the thermo-mechanical behaviour in Laser Forming, accounting for various part geometries, Laser process conditions and many materials. Although these interactions of thermal and mechanical factors are not yet fully understood, with increased knowledge of the Laser Forming process, the process offers significant potential value to industry such as aerospace, shipbuilding, microelectronics, etc. Modelling of the Laser Forming process may help to provide a basis for determining the heating pattern required, therefore making application of Laser Forming feasible and profitable to industry. This review describes a number of recent developments and new techniques in modelling of Laser Forming, including analytical models, numerical simulations and various empirical models.
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Modelling of Laser Forming – An review
Computational Materials Science, 2009Co-Authors: Hong Shen, Frank VollertsenAbstract:Abstract Laser Forming is achieved by plastic deformation induced by thermal stresses resulting from rapid nonlinear thermal cycles. Unlike mechanical Forming, the process requires no hard tooling or external forces and thus there is no spring-back effect. A number of mechanisms have been identified to explain the thermo-mechanical behaviour in Laser Forming, accounting for various part geometries, Laser process conditions and many materials. Although these interactions of thermal and mechanical factors are not yet fully understood, with increased knowledge of the Laser Forming process, the process offers significant potential value to industry such as aerospace, shipbuilding, microelectronics, etc. Modelling of the Laser Forming process may help to provide a basis for determining the heating pattern required, therefore making application of Laser Forming feasible and profitable to industry. This review describes a number of recent developments and new techniques in modelling of Laser Forming, including analytical models, numerical simulations and various empirical models.
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Study on mechanical properties after Laser Forming
Optics and Lasers in Engineering, 2009Co-Authors: Hong Shen, Zhenqiang YaoAbstract:Abstract Laser Forming is a means of processing materials in a novel manner. The mechanical properties of specimens after Laser Forming are investigated. By tension tests, the tension properties are analyzed to establish Ramberg–Osgood constitutive equations under different Laser processing parameters. Experimental data show that the yield strength and tensile strength are improved after Laser Forming, while the elongation percentage is reduced. Based on the distribution of residual stresses as well as residual strains after the Laser Forming process, the fatigue life under different Laser processing parameters is studied using low-cycle fatigue tests. The residual compressive plastic strain is the most important reason for improving the fatigue life of low carbon steel after Laser Forming. The fatigue fracture mechanism is shown through the analysis of macro-fracture and micro-fracture using the scanning electronic microscope.
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Research on the Mechanisms of Laser Forming for the Micro-Structural Element
Materials Science Forum, 2008Co-Authors: Ying Jin, Hong Shen, Yongjun Shi, Zheng Qiang YaoAbstract:Laser Forming of a micro-structural element involves a complex thermoplastic process. Numerous efforts had been made on the mechanisms of Laser Forming for macro-size elements, such as temperature gradient mechanism, buckling mechanism and upsetting mechanism, etc. It is found that the three mechanisms cannot depict fully the process of deformation in the macro-size element Forming, let alone meet the needs of the micro-size one. Considering the Laser inducing thermal stresses with size factors differing from the conventional analysis, it is essential to reveal the mechanisms dominating the Forming process to accurately control the bending angle of a tiny plate. By studying the thermal transfer and elastic-plastic deformation of micro-structural element Laser Forming, the Forming mechanism is explained within the micro size. The finite element model for Laser bending is constructed for simulation. The stimulation results are agreement with the experimental data.
Yongjun Shi - One of the best experts on this subject based on the ideXlab platform.
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Research on the Mechanisms of Laser Forming for the Micro-Structural Element
Materials Science Forum, 2008Co-Authors: Ying Jin, Hong Shen, Yongjun Shi, Zheng Qiang YaoAbstract:Laser Forming of a micro-structural element involves a complex thermoplastic process. Numerous efforts had been made on the mechanisms of Laser Forming for macro-size elements, such as temperature gradient mechanism, buckling mechanism and upsetting mechanism, etc. It is found that the three mechanisms cannot depict fully the process of deformation in the macro-size element Forming, let alone meet the needs of the micro-size one. Considering the Laser inducing thermal stresses with size factors differing from the conventional analysis, it is essential to reveal the mechanisms dominating the Forming process to accurately control the bending angle of a tiny plate. By studying the thermal transfer and elastic-plastic deformation of micro-structural element Laser Forming, the Forming mechanism is explained within the micro size. The finite element model for Laser bending is constructed for simulation. The stimulation results are agreement with the experimental data.
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Varying velocity scan in Laser Forming of plates
Materials Science and Technology, 2007Co-Authors: H. Shen, J. Zhou, Yongjun Shi, Zhenqiang YaoAbstract:Laser Forming of metal plates offers the advantages of requiring no external forces, cost reduction and increasing flexibility. It also enables Forming of some materials and shapes that are impossible by using the traditional methods. This paper presents a three-dimensional non-linear, indirectly coupled thermal structural model to simulate the process of Laser Forming of plates. The model is used to investigate the edge effects of the Laser bending. To verify the model, bending angles along the scan path simulated are compared with those measured experimentally. The results show that the numerical results are consistent with the experimental observations. The present numerical study shows that if the scan speed varies properly, the edge effect can be reduced significantly.
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The simulation of temperature field in the Laser Forming of steel plates
International Journal of Modelling Identification and Control, 2007Co-Authors: Hong Shen, Zhenqiang Yao, Yongjun ShiAbstract:Laser Forming of metal plates is a flexible Forming process that forms sheet by means of thermal stresses induced by external heat source instead of using external forces. The stresses are generated by temperature gradient induced by Laser. In this paper, a finite element analysis model including convective and radiation boundary conditions to predict the three-dimensional temperature field is established for a metal plate under the influence of a moving Gaussian heat source. The effects of various Laser Forming parameters on temperature distributions are investigated using the established model. By using variable scanning velocities a constant temperature gradient in the plate plane is achieved, which can be used to accurately form differently desired shapes of the plate.
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An analytical model for estimating deformation in Laser Forming
Computational Materials Science, 2006Co-Authors: Hong Shen, Yongjun Shi, Zhenqiang YaoAbstract:Abstract Laser Forming of metal sheets offers the advantages of requiring no external forces and thus reduces cost and increases flexibility. This paper presents an analytical model to estimate the angle bent during the Laser Forming of a sheet. Plastic deformation is considered during both heating and cooling and is calculated based on a history-dependent incremental stress–strain relationship. On the basis of the proposed model with known temperature distributions, the bending angle induced by Laser can be calculated. Comparison of the present model with experiment data is provided to demonstrate the accuracy of the present model under both TGM and BM.
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Application of similarity theory in the Laser Forming process
Computational Materials Science, 2006Co-Authors: Yongjun Shi, Hong Shen, Zhenqiang Yao, Lei XiaAbstract:Laser Forming is a flexible Forming technology. The deformation in the Laser Forming process primarily depends on process parameters, workpiece geometry and material properties. To acquire a comprehensive understanding of the deformation, numerous experiments are needed. However, sometimes the plate is huge, which leads to a high experimental expense. To reduce the number and the expense of the experiments, similarity method is adopted and the similarity conditions are derived using the dimensions theory. Numerical simulations of the real and similar plates are carried out. The comparison between the real and similar plate shows a good similarity in the temperature and deformation field.
Zhenqiang Yao - One of the best experts on this subject based on the ideXlab platform.
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Mixed-dimensional coupling modeling for Laser Forming process
Proceedings of the Institution of Mechanical Engineers Part C: Journal of Mechanical Engineering Science, 2014Co-Authors: Hong Shen, Zhenqiang YaoAbstract:Efficient Laser Forming modeling for industrial application is still in the developing stage and many researchers are in the process of modifying it. Conventional three-dimensional finite element models are still expensive on computational time. In this paper, a finite element model adopting a shell-solid coupling technique is developed for the thermomechanical analysis of Laser Forming process. In the shell-solid coupling method, an additional shell element plane is utilized to transfer heat flux and displacement from the solid elements to the shell elements. The effects of the additional interface shell element thickness on temperature distribution and final distortion are investigated. The presented shell-solid coupling method is evaluated by the results of three-dimensional simulations and experimental data.
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Study on mechanical properties after Laser Forming
Optics and Lasers in Engineering, 2009Co-Authors: Hong Shen, Zhenqiang YaoAbstract:Abstract Laser Forming is a means of processing materials in a novel manner. The mechanical properties of specimens after Laser Forming are investigated. By tension tests, the tension properties are analyzed to establish Ramberg–Osgood constitutive equations under different Laser processing parameters. Experimental data show that the yield strength and tensile strength are improved after Laser Forming, while the elongation percentage is reduced. Based on the distribution of residual stresses as well as residual strains after the Laser Forming process, the fatigue life under different Laser processing parameters is studied using low-cycle fatigue tests. The residual compressive plastic strain is the most important reason for improving the fatigue life of low carbon steel after Laser Forming. The fatigue fracture mechanism is shown through the analysis of macro-fracture and micro-fracture using the scanning electronic microscope.
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Varying velocity scan in Laser Forming of plates
Materials Science and Technology, 2007Co-Authors: H. Shen, J. Zhou, Yongjun Shi, Zhenqiang YaoAbstract:Laser Forming of metal plates offers the advantages of requiring no external forces, cost reduction and increasing flexibility. It also enables Forming of some materials and shapes that are impossible by using the traditional methods. This paper presents a three-dimensional non-linear, indirectly coupled thermal structural model to simulate the process of Laser Forming of plates. The model is used to investigate the edge effects of the Laser bending. To verify the model, bending angles along the scan path simulated are compared with those measured experimentally. The results show that the numerical results are consistent with the experimental observations. The present numerical study shows that if the scan speed varies properly, the edge effect can be reduced significantly.
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The simulation of temperature field in the Laser Forming of steel plates
International Journal of Modelling Identification and Control, 2007Co-Authors: Hong Shen, Zhenqiang Yao, Yongjun ShiAbstract:Laser Forming of metal plates is a flexible Forming process that forms sheet by means of thermal stresses induced by external heat source instead of using external forces. The stresses are generated by temperature gradient induced by Laser. In this paper, a finite element analysis model including convective and radiation boundary conditions to predict the three-dimensional temperature field is established for a metal plate under the influence of a moving Gaussian heat source. The effects of various Laser Forming parameters on temperature distributions are investigated using the established model. By using variable scanning velocities a constant temperature gradient in the plate plane is achieved, which can be used to accurately form differently desired shapes of the plate.
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An analytical model for estimating deformation in Laser Forming
Computational Materials Science, 2006Co-Authors: Hong Shen, Yongjun Shi, Zhenqiang YaoAbstract:Abstract Laser Forming of metal sheets offers the advantages of requiring no external forces and thus reduces cost and increases flexibility. This paper presents an analytical model to estimate the angle bent during the Laser Forming of a sheet. Plastic deformation is considered during both heating and cooling and is calculated based on a history-dependent incremental stress–strain relationship. On the basis of the proposed model with known temperature distributions, the bending angle induced by Laser can be calculated. Comparison of the present model with experiment data is provided to demonstrate the accuracy of the present model under both TGM and BM.
J. Magee - One of the best experts on this subject based on the ideXlab platform.
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Strain Gauge Analysis of Laser Forming
Journal of Laser Applications, 2003Co-Authors: Stuart Edwardson, Ken Watkins, Geoff Dearden, P. French, Stuart Edwardson, Geoff Dearden, Ken Watkins, P. French, J. MageeAbstract:Laser Forming has become a viable process for the shaping of metallic components, as a means of rapid prototyping and of adjusting and aligning. The Laser Forming process is of significant value to industries that previously relied on expensive stamping dies and presses for prototype evaluations. This investigation aims to complement the considerable amount of work already completed on two-dimensional Laser Forming, offering an insight into the mechanical behavior of a part during the process using a strain gauge analysis technique. The investigation was performed on mild steel CR4 sheet using a CO2 Laser source. It includes empirical investigations to determine optimum processing parameters using the temperature gradient mechanism, thermocouple analysis to locate ideal strain gauge placement for temperature compensation, and strain gauge analysis of the transverse localized strains at a number of locations on the surface of the sheet during single and multipass Laser Forming. The results of the investiga...
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Strain gauge analysis of Laser Forming
International Congress on Applications of Lasers & Electro-Optics, 2002Co-Authors: Stuart Edwardson, Ken Watkins, Geoff Dearden, P. French, Stuart Edwardson, Geoff Dearden, Ken Watkins, P. French, J. MageeAbstract:Laser Forming has become a viable process for the shaping of metallic components, as a means of rapid prototyping and of adjusting and aligning. The Laser Forming process is of significant value to industries that previously relied on expensive stamping dies and presses for prototype evaluations. This investigation aims to complement the considerable amount of work already completed on two-dimensional Laser Forming, offering an insight into the mechanical behaviour of a part during the process using a strain gauge analysis technique. The investigation was performed on Mild Steel CR4 sheet using a CO2 Laser source. It includes empirical investigations to determine optimum processing parameters using the temperature gradient mechanism, thermocouple analysis to locate ideal strain gauge placement for temperature compensation and strain gauge analysis of the transverse localised strains at a number of locations on the surface of the sheet during single and multi-pass Laser Forming. The results of the investigation demonstrate the relative complexity of the process even during a simple straight-line bend and that a residual strain component remains in the sheet after processing.Laser Forming has become a viable process for the shaping of metallic components, as a means of rapid prototyping and of adjusting and aligning. The Laser Forming process is of significant value to industries that previously relied on expensive stamping dies and presses for prototype evaluations. This investigation aims to complement the considerable amount of work already completed on two-dimensional Laser Forming, offering an insight into the mechanical behaviour of a part during the process using a strain gauge analysis technique. The investigation was performed on Mild Steel CR4 sheet using a CO2 Laser source. It includes empirical investigations to determine optimum processing parameters using the temperature gradient mechanism, thermocouple analysis to locate ideal strain gauge placement for temperature compensation and strain gauge analysis of the transverse localised strains at a number of locations on the surface of the sheet during single and multi-pass Laser Forming. The results of the investig...
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Generation of 3D Shapes Using a Laser Forming Technique
International Congress on Applications of Lasers & Electro-Optics, 2001Co-Authors: Stuart Edwardson, Geoff Dearden, Ken Watkins, J. MageeAbstract:There has been a considerable amount of work carried out on two-dimensional Laser Forming, using multi-pass straight line scan strategies to produce a reasonably controlled bend angle in a number of materials, including aerospace alloys. However in order to advance the process further for realistic Forming applications and for straightening and aligning operations in a manufacturing industry it is necessary to consider larger scale 3D Laser Forming. It is possible to form complex 3D surfaces from flat sheet material in a controlled way using a non-contact Laser Forming approach, thus eliminating the need for expensive dies. The technique can also be used to align or correct pre-formed 3D surfaces. This investigation demonstrates the 3D Laser Forming of a saddle shape from flat sheet mild steel using a CO2 Laser source. The double curvature of the saddle provides a useful case study with which to build up the design rules for such 3D surfaces. However the results of the investigation show that the problem of 3D Laser Forming is extremely complex. It was found that once a successful scan strategy was discovered symmetry was difficult to achieve due to the asymmetrical nature of the Forming process itself, in that it was not possible to form the whole sheet at the same time.There has been a considerable amount of work carried out on two-dimensional Laser Forming, using multi-pass straight line scan strategies to produce a reasonably controlled bend angle in a number of materials, including aerospace alloys. However in order to advance the process further for realistic Forming applications and for straightening and aligning operations in a manufacturing industry it is necessary to consider larger scale 3D Laser Forming. It is possible to form complex 3D surfaces from flat sheet material in a controlled way using a non-contact Laser Forming approach, thus eliminating the need for expensive dies. The technique can also be used to align or correct pre-formed 3D surfaces. This investigation demonstrates the 3D Laser Forming of a saddle shape from flat sheet mild steel using a CO2 Laser source. The double curvature of the saddle provides a useful case study with which to build up the design rules for such 3D surfaces. However the results of the investigation show that the problem ...
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A Prototype Laser Forming system
Optics and Lasers in Engineering, 2000Co-Authors: J. Magee, J. Sidhu, R. L. CookeAbstract:A non-contact Laser Forming (LF) demonstrator system was developed to demonstrate the process on a large primitive shape. The research that led to this development is described in this article. A fundamental study was carried out which examined the effects of Laser-Forming parameters on tokens of an aluminium and a titanium alloy. Energy, geometrical and metallurgical influences were investigated and are summarised here. Results of the study showed that LF of these aerospace materials is possible using a large operating envelope of Laser-processing parameters. A range of metallurgical effects resulted on the titanium alloy and these are traced here. Depending on how the energy input was supplied to the plate surface, various geometrical effects resulted. These effects are discussed. Using the knowledge gathered from the fundamental study, a prototype LF system was built. The components of the system and the Forming of a primitive shape on it are discussed. Conclusions from the study indicate that the future work lies in the development of the demonstrator for primitive 3-D shapes and the integration of a knowledge-based system.
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Symmetrical Laser Forming
International Congress on Applications of Lasers & Electro-Optics, 1999Co-Authors: J. Magee, K. G. Watkins, T. HennigeAbstract:The objective of this investigation was to establish rules about the positioning and sequencing of the Laser irradiation lines for symmetrical Laser Forming of a curved part. A flat circular plate was formed into a dome shape. It possesses axi-symmetry and this simplified the objective, as this was one of the first attempts reported in Laser Forming of curved parts. Laser irradiation conditions and scan patterns were implemented which resulted in an asymmetric Forming, and then a more regular Forming. This facilitated the establishment of the parameter - symmetry relationship. The scan patterns used in the investigation included star, offset, dividing, and circle line systems. Each system employed radial or circular scan lines, or a combination of both. These systems are described. The geometries of the formed parts were characterised with a co-ordinate measuring machine. They are presented.Results showed that the most important rules include reaching geometrical symmetry as soon as possible after each increment of Forming, and distributing the temperature symmetrically over the plate surface. It was found that pre-orientation bends should be avoided, and that the Laser beam parameters, particularly the irradiation angle and spot diameter influence the working accuracy. To comply with these rules it was concluded that the dividing systems and circle line systems provided the optimum Forming result.The objective of this investigation was to establish rules about the positioning and sequencing of the Laser irradiation lines for symmetrical Laser Forming of a curved part. A flat circular plate was formed into a dome shape. It possesses axi-symmetry and this simplified the objective, as this was one of the first attempts reported in Laser Forming of curved parts. Laser irradiation conditions and scan patterns were implemented which resulted in an asymmetric Forming, and then a more regular Forming. This facilitated the establishment of the parameter - symmetry relationship. The scan patterns used in the investigation included star, offset, dividing, and circle line systems. Each system employed radial or circular scan lines, or a combination of both. These systems are described. The geometries of the formed parts were characterised with a co-ordinate measuring machine. They are presented.Results showed that the most important rules include reaching geometrical symmetry as soon as possible after each in...
