Product design-Process selection-Process planning Integration based on Modelling and Simulation

As a solution for traditional design process having many drawbacks in the manufacturing process, the integration of Product design-Process selection-Process planning is carried out in the early design phase. The technological, economic, and logistic parameters are taken into account simultaneously as well as manufacturing constraints being integrated into the product design. As a consequence, the most feasible alternative with regard to the product’s detailed design is extracted satisfying the product’s functional requirements. Subsequently, a couple of conceptual process plans are proposed relied on manufacturing processes being preliminarily selected in the conceptual design phase. Virtual manufacturing is employed under CAM software to simulate fabrication process of the potential process plans. Ultimately, the most suitable process plan for fabricating the part is recommended based upon a multi-criteria analysis as a resolution for decision making

Product design-Process selection-Process planning Integration based on Modeling and Simulation of Manufacturing Process

As a solution for traditional design process having many drawbacks in the manufacturing process, the integration of Product design-Process selection-Process planning is carried out in the early design phase. The technological, economic, and logistic parameters are taken into account simultaneously as well as manufacturing constraints being integrated into the product design. As a consequence, the most feasible alternative with regard to the product’s detailed design is extracted satisfying the product’s functional requirements. Subsequently, a couple of conceptual process plans are proposed relied on manufacturing processes being preliminarily selected in the conceptual design phase. As a result, virtual manufacturing is employed under DELMIA software to simulate fabrication process of the potential process plans. Ultimately, the most suitable process plan for fabricating the part is recommended based upon a multi-criteria analysis as a resolution for decision makin

Validation et optimisation robuste d’un procédé d’emboutissage par simulation en contexte incertain

The ultimate objective of this thesis is to evaluate the possibility to validate and optimize a manufacturing process using numerical simulation and taking into account the irreducible uncertainties in the process, materials and geometry of manufactured product. Taking into account the uncertainties requires quantifying the effects of variations of model parameters on the outputs, by propagating these variations via computer simulation to assess their effects on the outputs. In this work, we have proposed a procedure to determine the sensitivity threshold of the numerical model to build numerical Design of Experiments consistent with this threshold. We have also shown that, given the uncertainties in the materials and the geometry of the product, it is possible to optimize certain process parameters to control the effects of uncertainties on the dimensional and morphological variations of the product. For this, we have proposed an optimization procedure based on NSGA-II algorithm and a meta-modeling of the process. The application for deep drawing of a U-shaped sheet metal part, springback included shows that it is a robust design problem for which we get all the compromise between the deviation from the mean and standard deviation of a "performance" depending on the process correctly chosen. Finally, the analysis of these results allows us to quantify the relationship between the notion of robustness of an optimized solution of the process and criteria for measuring the quality of the productL’objectif ultime de ce travail de thèse est d’évaluer la possibilité de valider et d’optimiser un processus de fabrication en utilisant la simulation numérique en tenant compte des incertitudes irréductibles sur le procédé, les matériaux et la géométrie du produit fabriqué. La prise en compte des incertitudes nécessite de quantifier les effets des variations des paramètres du modèle sur les sorties de celui-ci, en propageant ces variations via la simulation numérique pour évaluer leurs effets sur les sorties. Dans ce travail nous avons proposé une procédure pour déterminer le seuil de sensibilité du modèle numérique afin de construire des plans d’expériences numériques cohérents avec ce seuil. Nous avons également montré que, compte tenu des incertitudes sur les matériaux et la géométrie du produit, il est possible d’optimiser certains paramètres du procédé pour contrôler les effets des incertitudes sur les variations dimensionnelles et morphologiques du produit. Pour cela, nous avons proposé une procédure d’optimisation basée sur un algorithme NSGA-II et une méta-modélisation du procédé. L’application à l’emboutissage d’une tôle en U, retour élastique inclus, montre qu’il s’agit d’un problème de conception robuste pour lequel nous obtenons l’ensemble des compromis entre l’écart à la moyenne et l’écart type d’une fonction « performance » du procédé correctement choisie. Finalement l’analyse de ces résultats nous permet de quantifier le lien entre la notion de robustesse d’une solution optimisée du procédé et les critères de mesure de la qualité du produi

Multi-objective optimization under uncertainty for sheet metal forming

International audienceAleatory uncertainties in material properties, blank thickness and friction condition are inherent and irreducible variabilities in sheet metal forming. Optimal design configurations, which are obtained by conventional design optimization methods, are not always able to meet the desired targets due to the effect of uncertainties. This paper proposes a multi-objective robust design optimization that aims to tackle this problem. Results obtained on a U shape draw bending benchmark show that spring-back effect can be controlled by optimizing process parameters

Critère de décision basé sur les indices de capabilité pour l’optimisation robuste d’un procédé d’emboutissage

International audienceThis paper proposes a framework for robust optimization along with a making decision support based on process capability index. This framework is helpful for designers, in order to estimate the effect of uncertainty in manufacturing processes on functional specification on the product to be designed. This framework aims to evaluate the capability of a chosen process to handled functional specification, and if not, to optimize the manufacturing process to fit functional specifications. This framework is illustrated with a simple example of a sheet metal forming and the specification of the deviation of a hole position on the stamped part. Results show that several compromises along the Pareto front are reachable with respect to the chosen process capability index.Cet article propose une démarche d’optimisation robuste associée à un critère de décision basé sur les indices de capabilité d’un procédé pour prendre en compte lors de la spécification d’un tolérancement sur un produit les effets des incertitudes irréductibles liées au procédé et au produit. L’objectif de la démarche est de savoir si le procédé envisagé, compte tenu des incertitudes, est compatible avec les spécifications fonctionnelles du produit et le cas échéant d’optimiser le procédé pour tenter de satisfaire les spécifications choisies. La démarche est illustrée par l’exemple du tolérancement de la déviation de position d’un perçage sur une pièce en tôle emboutie. L’exemple traité montre que plusieurs compromis de Pareto sont atteignables en fonction du choix du type d’indice de capabilité

Assessment of Sensitivity of Numerical Simulation in Sheet Metal Forming Process Applied for Robust Design

International audienceConsidering variation of influent factors is a critical issue to enhance the robustness of sheet metal forming process in the product design process. The stochastic variability of uncontrollable factors results in the variations on the formed part which can lead to rejected parts. Since the inherent sources of variation in the sheet metal forming process comes from part-to-part, within batch and batch-to-batch variation. Therefore, the prediction and control of the variability influencing on the performance of the product is an essential demand of automotive and aeronautic manufacturers. Moreover, it is very necessary to have a numerically dedicated tool which predicts the process variability with a good confidence. In this paper, prediction of the variations of the formed part due to the variabilities of the sheet stamping process and the workpiece by numerical simulation will be carried out

Multi-Objective Optimization under Uncertainty and Decision-Making Support for Sheet Metal Forming

International audienceUncertainty is inevitable in sheet metal metal forming process. Aleatory uncertainties in material properties, blank thickness and friction condition are inherent irreducible variabilities in sheetmetal forming. However, optimal design configurations which are obtained by conventional designoptimization methods are not always able to meet the desired targets due to the effect of uncertainties.In order to tackle this problem, a multi-objective robust design optimization (MORDO) applied forsheet metal draw bending process is introduced in this paper. In addition, since the MORDO of sheetmetal forming involves considering serveral conflicting criteria, a Pareto multiple objective criteriadecision-making approach based on capability indices is proposed

Critère de décision basé sur les indices de capabilité pour l’optimisation robuste d’un procédé d’emboutissage

International audienceThis paper proposes a framework for robust optimization along with a making decision support based on process capability index. This framework is helpful for designers, in order to estimate the effect of uncertainty in manufacturing processes on functional specification on the product to be designed. This framework aims to evaluate the capability of a chosen process to handled functional specification, and if not, to optimize the manufacturing process to fit functional specifications. This framework is illustrated with a simple example of a sheet metal forming and the specification of the deviation of a hole position on the stamped part. Results show that several compromises along the Pareto front are reachable with respect to the chosen process capability index.Cet article propose une démarche d’optimisation robuste associée à un critère de décision basé sur les indices de capabilité d’un procédé pour prendre en compte lors de la spécification d’un tolérancement sur un produit les effets des incertitudes irréductibles liées au procédé et au produit. L’objectif de la démarche est de savoir si le procédé envisagé, compte tenu des incertitudes, est compatible avec les spécifications fonctionnelles du produit et le cas échéant d’optimiser le procédé pour tenter de satisfaire les spécifications choisies. La démarche est illustrée par l’exemple du tolérancement de la déviation de position d’un perçage sur une pièce en tôle emboutie. L’exemple traité montre que plusieurs compromis de Pareto sont atteignables en fonction du choix du type d’indice de capabilité

Influence of part geometrical tolerancing in the REFM methodology

International audienceThis paper deals with the remanufacturing of existing part in a context of Reverse Engineering (RE). The proposed methodology called Reverse Engineering for Manufacturing (REFM) consists in generating a Computer Aided Process Planning (CAPP) of a part from 3D information, point cloud, and user knowledge. The idea of this methodology is to avoid the passage by the CAD model. Steps of this methodology are based on a Surface Precedence Graph (SPG) build on a suggested geometrical tolerancing of the part. This graph leads to machining operation precedence graph (MOPG) that leads to the CAPP model. A problem of this approach is that different tolerancing of the same part lead to different process planning. To solve this problem, rules are presented to facilitate the user work. This paper presents the REFM methodology illustrated on a study case