The Experts below are selected from a list of 210 Experts worldwide ranked by ideXlab platform
Xavier Cerutti - One of the best experts on this subject based on the ideXlab platform.
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Numerical prediction of distorsions during Machining of large aluminum aeronautical parts
2017Co-Authors: Katia Mocellin, Xavier CeruttiAbstract:Aluminium alloy structural aerospace parts are usually large monolithic parts machined from rolled plates or preformed parts. Previous to Machining, several manufacturing steps (forming, heat treatments and mechanical stress relief operations) are performed, resulting in the creation of residual stresses. During Machining, a redistribution of the residual stresses occurs due to the material removal. This residual stress redistribution is the main reason for Machining errors such as dimensional variations and post-Machining distortions. In order to predict the mechanical behaviour of the workpiece during Machining and the final part quality in taking into consideration both the Machining parameters (fixture layout and Machining Sequence) and the residual stress redistribution, a specific numerical tool has been developed [Cerutti & Mocellin, 2014]. Using this numerical tool, an analysis of the influence of the initial residual stresses as well as of the fixture layout and the Machining Sequences (tool path) on the Machining quality of parts machined from an AIRWARE®2050-T84 alloy rolled plate is performed. The numerical results are compared with experimental ones in terms of both post-Machining distortions and dimensional errors. Similar results are obtained for both, showing that the developed numerical tool allows to predict dimensional and geometrical errors due to the redistribution of the residual stresses during Machining. The Machining of these cases and results obtained are then analysed, demonstrating the feasibility to adapt and to optimize the Machining process plan to ensure conformity of the part with the tolerance specifications.
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Influence of the Machining Sequence on the residual stress redistribution and Machining quality: analysis and improvement using numerical simulations
International Journal of Advanced Manufacturing Technology, 2017Co-Authors: Xavier Cerutti, Katia MocellinAbstract:The manufacturing of aluminium alloy structural aerospace parts involves multiple steps, the principal ones being the forming (rolling, forging etc.), the heat treatments and the Machining. During this last step, the final geometry of the part is obtained. Before Machining, the workpiece has therefore undergone several manufacturing steps resulting in unequal plastic deformation and metallurgical changes which are both sources of residual stresses. On large and complex aluminium alloy aeronautical parts, up to 90 % of the initial workpiece volume can be removed by Machining. During Machining, the mechanical equilibrium of the part is in constant evolution due to the redistribution of the initial residual stresses.The residual stress redistribution is the main cause of workpiece deflections during Machining as well as of post-Machining distortion (after unclamping). Both can lead to the non-conformity of the part with the geometrical and dimensional tolerance specifications and therefore to a rejection of the part or to additional conforming steps. In order to improve the Machining accuracy and the robustness of the process, the effect of the residual stresses has to be considered for the definition of the Machining process plan. In this paper, a specific numerical tool [2] allowing to predict workpiece deflections during Machining and post-Machining distortion is used to study the influence of the Machining Sequence on the Machining quality in taking into consideration the initial residual stresses. A first Machining process plan defined as the reference case is simulated. Simulation results are then compared with experimental ones showing the feasibility to use the developed tool to predict the Machining quality depending on the initial residual stresses, the fixture layout and the Machining Sequence. Using the computational tool, a method to optimise the Machining quality depending on the initial workpiece and on the Machining Sequence is presented. A Machining process plan allowing to respect the tolerance specifications is then defined. This demonstrates the feasibility to adapt and to optimise the Machining process plan to ensure conformity of the part with the tolerance specifications.
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Numerical prediction of distortions during Machining of large aluminium aeronautical parts
Materials Science and Engineering Technology Materialwissenschaft und Werkstofftechnik, 2016Co-Authors: Katia Mocellin, Xavier CeruttiAbstract:Aluminium alloy structural aerospace parts are usually large monolithic parts machined from rolled plates or preformed parts. Previous to Machining, several manufacturing steps (forming, heat treatments and mechanical stress relief operations) are performed, resulting in the creation of residual stresses. During Machining, a redistribution of the residual stresses occurs due to the material removal. This residual stress redistribution is the main reason for Machining errors such as dimensional variations and post-Machining distortions. In order to predict the mechanical behaviour of the workpiece during Machining and the final part quality in taking into consideration both the Machining parameters (fixture layout and Machining Sequence) and the residual stress redistribution, a specific numerical tool has been developed [1]. Using this numerical tool, an analysis of the influence of the initial residual stresses as well as of the fixture layout and the Machining Sequences (tool path) on the Machining quality of parts machined from an AIRWARE®2050-T84 alloy rolled plate is performed. The numerical results are compared with experimental ones in terms of both post-Machining distortions and dimensional errors. Similar results are obtained for both, showing that the developed numerical tool allows to predict dimensional and geometrical errors due to the redistribution of the residual stresses during Machining. The Machining of these cases and results obtained are then analysed, demonstrating the feasibility to adapt and to optimize the Machining process plan to ensure conformity of the part with the tolerance specifications.
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Methodology for aluminium part Machining quality improvement considering mechanical properties and process conditions
CIRP Journal of Manufacturing Science and Technology, 2016Co-Authors: Xavier Cerutti, Sami Hassini, Katia Mocellin, Benoit Blaysat, Emmanuel DucAbstract:The manufacturing of structural aluminium alloy parts requires several steps of both forming processes and heat treatments. Before Machining, which is usually the last step of the manufacturing, the workpiece has thus undergone multiple manufacturing steps involving unequal plastic deformations which are source of residual stresses. During Machining, where up to 90% of the initial workpiece volume can be removed, the mechanical equilibrium of the part evolves constantly with the redistribution of the initial residual stresses. For thick, large and complex parts in highly alloyed aluminium, this redistribution of the residual stresses can leads to an unexpected behaviour of the workpiece and is the main reason for both workpiece deflections (during Machining) and post-Machining distortions (after unclamping). These two phenomena can lead to the nonconformity of the part with the geometrical and dimensional tolerance specifications and therefore to the rejection of the part or to additional conforming steps. As a conSequence, the mechanical behaviour of the workpiece has to be considered during the definition of the Machining process plan to improve the Machining accuracy and the robustness of the process and thus to ensure the conformity of the machined part with the dimensional and geometrical specifications, i.e. to ensure the desired Machining quality. In this paper, the numerical tool developed in [1] is used to conduct an analysis on the influence of the initial workpiece residual stress state, of the fixture layout as well as of the Machining Sequence on the Machining quality. This analysis is performed on a part which has been specially designed and which can be considered as being representative of real aerospace parts. Several comparisons with experimental results are performed, one of them using digital image correlation (DIC) measurements. Results obtained show a good agreement, validating both the prediction of the behaviour of the workpiece during Machining and the prediction of the machined part geometry. Based on the results of this analysis, a classification of the parameters has been performed depending on their influence on the Machining quality. A first methodology allowing to define Machining process plans adapted to the initial workpiece stress state has then been created based on the previous classification. This methodology is composed of a procedure and basic guidelines which are both presented in detail. An example of an application of this methodology is then introduced, demonstrating the benefits of the approach developed in this work.
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Influence of the Machining Sequence on the residual stress redistribution and Machining quality: analysis and improvement using numerical simulations
The International Journal of Advanced Manufacturing Technology, 2015Co-Authors: Xavier Cerutti, Katia MocellinAbstract:International audienceThe manufacturing of aluminium alloy structural aerospace parts involves multiple steps, the principal ones being the forming (rolling, forging etc.), the heat treatments and the Machining. During this last step, the final geometry of the part is obtained. Before Machining, the workpiece has therefore undergone several manufacturing steps resulting in unequal plastic deformation and metallurgical changes which are both sources of residual stresses. On large and complex aluminium alloy aeronautical parts, up to 90 % of the initial workpiece volume can be removed by Machining. During Machining, the mechanical equilibrium of the part is in constant evolution due to the redistribution of the initial residual stresses.The residual stress redistribution is the main cause of workpiece deflections during Machining as well as of post-Machining distortion (after unclamping). Both can lead to the non-conformity of the part with the geometrical and dimensional tolerance specifications and therefore to a rejection of the part or to additional conforming steps. In order to improve the Machining accuracy and the robustness of the process, the effect of the residual stresses has to be considered for the definition of the Machining process plan. In this paper, a specific numerical tool [2] allowing to predict workpiece deflections during Machining and post-Machining distortion is used to study the influence of the Machining Sequence on the Machining quality in taking into consideration the initial residual stresses. A first Machining process plan defined as the reference case is simulated. Simulation results are then compared with experimental ones showing the feasibility to use the developed tool to predict the Machining quality depending on the initial residual stresses, the fixture layout and the Machining Sequence. Using the computational tool, a method to optimise the Machining quality depending on the initial workpiece and on the Machining Sequence is presented. A Machining process plan allowing to respect the tolerance specifications is then defined. This demonstrates the feasibility to adapt and to optimise the Machining process plan to ensure conformity of the part with the tolerance specifications
Katia Mocellin - One of the best experts on this subject based on the ideXlab platform.
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Numerical prediction of distorsions during Machining of large aluminum aeronautical parts
2017Co-Authors: Katia Mocellin, Xavier CeruttiAbstract:Aluminium alloy structural aerospace parts are usually large monolithic parts machined from rolled plates or preformed parts. Previous to Machining, several manufacturing steps (forming, heat treatments and mechanical stress relief operations) are performed, resulting in the creation of residual stresses. During Machining, a redistribution of the residual stresses occurs due to the material removal. This residual stress redistribution is the main reason for Machining errors such as dimensional variations and post-Machining distortions. In order to predict the mechanical behaviour of the workpiece during Machining and the final part quality in taking into consideration both the Machining parameters (fixture layout and Machining Sequence) and the residual stress redistribution, a specific numerical tool has been developed [Cerutti & Mocellin, 2014]. Using this numerical tool, an analysis of the influence of the initial residual stresses as well as of the fixture layout and the Machining Sequences (tool path) on the Machining quality of parts machined from an AIRWARE®2050-T84 alloy rolled plate is performed. The numerical results are compared with experimental ones in terms of both post-Machining distortions and dimensional errors. Similar results are obtained for both, showing that the developed numerical tool allows to predict dimensional and geometrical errors due to the redistribution of the residual stresses during Machining. The Machining of these cases and results obtained are then analysed, demonstrating the feasibility to adapt and to optimize the Machining process plan to ensure conformity of the part with the tolerance specifications.
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Influence of the Machining Sequence on the residual stress redistribution and Machining quality: analysis and improvement using numerical simulations
International Journal of Advanced Manufacturing Technology, 2017Co-Authors: Xavier Cerutti, Katia MocellinAbstract:The manufacturing of aluminium alloy structural aerospace parts involves multiple steps, the principal ones being the forming (rolling, forging etc.), the heat treatments and the Machining. During this last step, the final geometry of the part is obtained. Before Machining, the workpiece has therefore undergone several manufacturing steps resulting in unequal plastic deformation and metallurgical changes which are both sources of residual stresses. On large and complex aluminium alloy aeronautical parts, up to 90 % of the initial workpiece volume can be removed by Machining. During Machining, the mechanical equilibrium of the part is in constant evolution due to the redistribution of the initial residual stresses.The residual stress redistribution is the main cause of workpiece deflections during Machining as well as of post-Machining distortion (after unclamping). Both can lead to the non-conformity of the part with the geometrical and dimensional tolerance specifications and therefore to a rejection of the part or to additional conforming steps. In order to improve the Machining accuracy and the robustness of the process, the effect of the residual stresses has to be considered for the definition of the Machining process plan. In this paper, a specific numerical tool [2] allowing to predict workpiece deflections during Machining and post-Machining distortion is used to study the influence of the Machining Sequence on the Machining quality in taking into consideration the initial residual stresses. A first Machining process plan defined as the reference case is simulated. Simulation results are then compared with experimental ones showing the feasibility to use the developed tool to predict the Machining quality depending on the initial residual stresses, the fixture layout and the Machining Sequence. Using the computational tool, a method to optimise the Machining quality depending on the initial workpiece and on the Machining Sequence is presented. A Machining process plan allowing to respect the tolerance specifications is then defined. This demonstrates the feasibility to adapt and to optimise the Machining process plan to ensure conformity of the part with the tolerance specifications.
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Numerical prediction of distortions during Machining of large aluminium aeronautical parts
Materials Science and Engineering Technology Materialwissenschaft und Werkstofftechnik, 2016Co-Authors: Katia Mocellin, Xavier CeruttiAbstract:Aluminium alloy structural aerospace parts are usually large monolithic parts machined from rolled plates or preformed parts. Previous to Machining, several manufacturing steps (forming, heat treatments and mechanical stress relief operations) are performed, resulting in the creation of residual stresses. During Machining, a redistribution of the residual stresses occurs due to the material removal. This residual stress redistribution is the main reason for Machining errors such as dimensional variations and post-Machining distortions. In order to predict the mechanical behaviour of the workpiece during Machining and the final part quality in taking into consideration both the Machining parameters (fixture layout and Machining Sequence) and the residual stress redistribution, a specific numerical tool has been developed [1]. Using this numerical tool, an analysis of the influence of the initial residual stresses as well as of the fixture layout and the Machining Sequences (tool path) on the Machining quality of parts machined from an AIRWARE®2050-T84 alloy rolled plate is performed. The numerical results are compared with experimental ones in terms of both post-Machining distortions and dimensional errors. Similar results are obtained for both, showing that the developed numerical tool allows to predict dimensional and geometrical errors due to the redistribution of the residual stresses during Machining. The Machining of these cases and results obtained are then analysed, demonstrating the feasibility to adapt and to optimize the Machining process plan to ensure conformity of the part with the tolerance specifications.
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Methodology for aluminium part Machining quality improvement considering mechanical properties and process conditions
CIRP Journal of Manufacturing Science and Technology, 2016Co-Authors: Xavier Cerutti, Sami Hassini, Katia Mocellin, Benoit Blaysat, Emmanuel DucAbstract:The manufacturing of structural aluminium alloy parts requires several steps of both forming processes and heat treatments. Before Machining, which is usually the last step of the manufacturing, the workpiece has thus undergone multiple manufacturing steps involving unequal plastic deformations which are source of residual stresses. During Machining, where up to 90% of the initial workpiece volume can be removed, the mechanical equilibrium of the part evolves constantly with the redistribution of the initial residual stresses. For thick, large and complex parts in highly alloyed aluminium, this redistribution of the residual stresses can leads to an unexpected behaviour of the workpiece and is the main reason for both workpiece deflections (during Machining) and post-Machining distortions (after unclamping). These two phenomena can lead to the nonconformity of the part with the geometrical and dimensional tolerance specifications and therefore to the rejection of the part or to additional conforming steps. As a conSequence, the mechanical behaviour of the workpiece has to be considered during the definition of the Machining process plan to improve the Machining accuracy and the robustness of the process and thus to ensure the conformity of the machined part with the dimensional and geometrical specifications, i.e. to ensure the desired Machining quality. In this paper, the numerical tool developed in [1] is used to conduct an analysis on the influence of the initial workpiece residual stress state, of the fixture layout as well as of the Machining Sequence on the Machining quality. This analysis is performed on a part which has been specially designed and which can be considered as being representative of real aerospace parts. Several comparisons with experimental results are performed, one of them using digital image correlation (DIC) measurements. Results obtained show a good agreement, validating both the prediction of the behaviour of the workpiece during Machining and the prediction of the machined part geometry. Based on the results of this analysis, a classification of the parameters has been performed depending on their influence on the Machining quality. A first methodology allowing to define Machining process plans adapted to the initial workpiece stress state has then been created based on the previous classification. This methodology is composed of a procedure and basic guidelines which are both presented in detail. An example of an application of this methodology is then introduced, demonstrating the benefits of the approach developed in this work.
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Influence of the Machining Sequence on the residual stress redistribution and Machining quality: analysis and improvement using numerical simulations
The International Journal of Advanced Manufacturing Technology, 2015Co-Authors: Xavier Cerutti, Katia MocellinAbstract:International audienceThe manufacturing of aluminium alloy structural aerospace parts involves multiple steps, the principal ones being the forming (rolling, forging etc.), the heat treatments and the Machining. During this last step, the final geometry of the part is obtained. Before Machining, the workpiece has therefore undergone several manufacturing steps resulting in unequal plastic deformation and metallurgical changes which are both sources of residual stresses. On large and complex aluminium alloy aeronautical parts, up to 90 % of the initial workpiece volume can be removed by Machining. During Machining, the mechanical equilibrium of the part is in constant evolution due to the redistribution of the initial residual stresses.The residual stress redistribution is the main cause of workpiece deflections during Machining as well as of post-Machining distortion (after unclamping). Both can lead to the non-conformity of the part with the geometrical and dimensional tolerance specifications and therefore to a rejection of the part or to additional conforming steps. In order to improve the Machining accuracy and the robustness of the process, the effect of the residual stresses has to be considered for the definition of the Machining process plan. In this paper, a specific numerical tool [2] allowing to predict workpiece deflections during Machining and post-Machining distortion is used to study the influence of the Machining Sequence on the Machining quality in taking into consideration the initial residual stresses. A first Machining process plan defined as the reference case is simulated. Simulation results are then compared with experimental ones showing the feasibility to use the developed tool to predict the Machining quality depending on the initial residual stresses, the fixture layout and the Machining Sequence. Using the computational tool, a method to optimise the Machining quality depending on the initial workpiece and on the Machining Sequence is presented. A Machining process plan allowing to respect the tolerance specifications is then defined. This demonstrates the feasibility to adapt and to optimise the Machining process plan to ensure conformity of the part with the tolerance specifications
Wasim A Khan - One of the best experts on this subject based on the ideXlab platform.
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NON-PRODUCTIVE TOOL PATH OPTIMIZATION FOR FOUR AXIS MILLING USING THE SIMULATED ANNEALING ALGORITHM
International Journal of Production Research, 2010Co-Authors: David R Hayhurst, Atef Atef Afifi, Wasim A KhanAbstract:The paper concerns the development of generic computer aided optimization techniques for the minimization of residence time of a multi-component pallet in a horizontal Machining centre. A general methodology has been established to take a part program for a multi-faced pallet, that involves many components, typically 20-30, and tool changes, segment it to extract the position and Machining conditions embedded in it, automatically re-Sequence the Machining operations to find the optimum total tool path, and regenerate a new part program with the optimized Machining Sequence. A range of case studies has been used to: validate the software, and to demonstrate its ability to minimize the total pallet residence time. The techniques developed can be used for semi-automatic part programming of the entire pallet with multi-components, and with an auto-selection multi-tool facility. The software is capable of achieving a large reduction in part programming time, as well reducing the non-Machining time. It is shown that the use of the optimization package with a range of part programs reduces the total pallet residence time by a factor between 9.5 and 36%, and consequently has the potential to achieve considerable economic gains.
Hyung Min Rho - One of the best experts on this subject based on the ideXlab platform.
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Integrated Machining tool path planning using feature free spaces
International Journal of Production Research, 2003Co-Authors: Yong Se Kim, Eric Wang, Il-kyu Hwang, Hyung Min RhoAbstract:We describe an automatic Machining tool path generation method that integrates local and global tool path planning for Machining features. From the solid model and the tolerance specifications of the part, we automatically recognize Machining features, and obtain the geometry-based precedence relations between these features. A separate process planning module uses this information to determine the Machining Sequence, tool selections, and Machining conditions. From the resulting process plan, we then generate Machining tool paths for each set-up, combining local and global tool paths. Machining features are expanded through their fictitious faces to obtain feature free spaces. These comprise the cells of a free space decomposition, which enables the use of established robot motion planning techniques. Global tool paths between features are generated incrementally by searching the adjacency graph of feature free spaces, which represents the free space of the part at each step of the process plan. Local too...
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Geometry-based Machining precedence reasoning for feature-based process planning
International Journal of Production Research, 2001Co-Authors: Yong Se Kim, Eric Wang, Hyung Min RhoAbstract:This paper presents a method to generate Machining precedence relations systematically based on the geometric information of the part. The feature recognition method using Alternating Sum of Volumes with Partitioning (ASVP) Decomposition is applied to obtain a Form Feature Decomposition (FFD) of a part model. Form features are classified into a taxonomy of atomic Machining features to which Machining process information has been associated. Geometry-based precedence relations between features are systematically generated using the face dependency information obtained by ASVP Decomposition and the features' associated Machining process information. Multiple sets of precedence relations are generated as alternative precedence trees based on the feature types and Machining process considerations. These precedence trees can be further enhanced with precedence relations from tolerance specifications and Machining expertise. Machining Sequence planning can be performed for each of these precedence trees while m...
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Feature-Based Machining Precedence Reasoning and Sequence Planning
Volume 6: 18th Computers in Engineering Conference, 1998Co-Authors: Yong Se Kim, Eric Wang, Choong Soo Lee, Hyung Min RhoAbstract:Abstract This paper presents a feature-based method to support Machining Sequence planning. Precedence relations among Machining operations are systematically generated based on geometric information, tolerance specifications, and Machining expertise. The feature recognition method using Alternating Sum of Volumes With Partitioning (ASVP) Decomposition is applied to obtain a Form Feature Decomposition (FFD) of a part model. Form features are classified into a taxonomy of atomic Machining features, to which Machining process information has been associated. Geometry-based precedence relations between features are systematically generated using the face dependency information obtained by ASVP Decomposition and the features’ associated Machining process information. Multiple sets of precedence relations are generated as alternative precedence trees, based on the feature types and Machining process considerations. These precedence trees are further enhanced with precedence relations from tolerance specifications and Machining expertise. Machining Sequence planning is performed for each of these precedence trees, applying a matrix-based method to reduce the search space while minimizing the number of tool changes. The precedence trees may then be evaluated based on Machining cost and other criteria. The precedence reasoning module and operation Sequence planning module are currently being implemented within a comprehensive Computer-Aided Process Planning system.
David R Hayhurst - One of the best experts on this subject based on the ideXlab platform.
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NON-PRODUCTIVE TOOL PATH OPTIMIZATION FOR FOUR AXIS MILLING USING THE SIMULATED ANNEALING ALGORITHM
International Journal of Production Research, 2010Co-Authors: David R Hayhurst, Atef Atef Afifi, Wasim A KhanAbstract:The paper concerns the development of generic computer aided optimization techniques for the minimization of residence time of a multi-component pallet in a horizontal Machining centre. A general methodology has been established to take a part program for a multi-faced pallet, that involves many components, typically 20-30, and tool changes, segment it to extract the position and Machining conditions embedded in it, automatically re-Sequence the Machining operations to find the optimum total tool path, and regenerate a new part program with the optimized Machining Sequence. A range of case studies has been used to: validate the software, and to demonstrate its ability to minimize the total pallet residence time. The techniques developed can be used for semi-automatic part programming of the entire pallet with multi-components, and with an auto-selection multi-tool facility. The software is capable of achieving a large reduction in part programming time, as well reducing the non-Machining time. It is shown that the use of the optimization package with a range of part programs reduces the total pallet residence time by a factor between 9.5 and 36%, and consequently has the potential to achieve considerable economic gains.
