A design-for-casting integrated approach based on rapid simulation and modulus criterion

This paper presents a new approach to the design of cast components and their associated tools. The current methodology is analysed through a case study and its main disadvantages underlined. Then, in order to overcome these identified drawbacks, a new approach is proposed. Knowing that this approach is mainly based on a rapid simulation of the process, basics of a simplified physical model of solidification are presented as well as an associated modulus criterion. Finally, technical matters for a software prototype regarding the implementation of this Rapid Simulation Approach (RSA) in a CAD environment are detailed

Repairing triangle meshes built from scanned point cloud

The Reverse Engineering process consists of a succession of operations that aim at creating a digital representation of a physical model. The reconstructed geometric model is often a triangle mesh built from a point cloud acquired with a scanner. Depending on both the object complexity and the scanning process, some areas of the object outer surface may never be accessible, thus inducing some deficiencies in the point cloud and, as a consequence, some holes in the resulting mesh. This is simply not acceptable in an integrated design process where the geometric models are often shared between the various applications (e.g. design, simulation, manufacturing). In this paper, we propose a complete toolbox to fill in these undesirable holes. The hole contour is first cleaned to remove badly-shaped triangles that are due to the scanner noise. A topological grid is then inserted and deformed to satisfy blending conditions with the surrounding mesh. In our approach, the shape of the inserted mesh results from the minimization of a quadratic function based on a linear mechanical model that is used to approximate the curvature variation between the inner and surrounding meshes. Additional geometric constraints can also be specified to further shape the inserted mesh. The proposed approach is illustrated with some examples coming from our prototype software

MACHINE TOOL, IN PARTICULAR FOR DRILLING

La présente invention concerne le domaine de l’usinage par enlèvement de matière. L’invention a ainsi pour objet une machine d’usinage et, plus particulièrement, une machine de perçage ou de fraisage. La machine à la particularité d’intégrer deux moteurs électriques destinés à contrôler les mouvements d’avance et de rotation d’un outil, tout en permettant une action d’assistance vibratoire, particulièrement utile pour le perçage de matériaux difficiles à usiner.The present invention relates to the field of machining of materials by chip removal. The invention presents a special machine tool and, more particularly, a drilling or milling machine. The machine has the particularity of incorporating two electric motors for controlling the feed and rotation motions of a tool, while allowing a vibration assistance optional motion, particularly useful for drilling hard to machine materials .Contrats et collaboration ARTS / AE

A design-for-casting integrated approach based on rapid simulation and modulus criterion

International audienceThis paper presents a new approach to the design of cast components and their associated tools. The current methodology is analysed through a case study and its main disadvantages underlined. Then, in order to overcome these identified drawbacks, a new approach is proposed. Knowing that this approach is mainly based on a rapid simulation of the process, basics of a simplified physical model of solidification are presented as well as an associated modulus criterion. Finally, technical matters for a software prototype regarding the implementation of this Rapid Simulation Approach (RSA) in a CAD environment are detailed

Vibratory machining device

The invention relates to a machining device comprising a supporting structure, a transmission shaft (3) and a drive mechanism (1) comprising a first meshing member (13) able to drive the rotation of said shaft about the axis (A) thereof, a second meshing member (17) in a helicoidal connection with said shaft in order to drive the translational movement of said shaft along the axis thereof in a feed movement, dependent on the relative rotational velocity of said first and second meshing members, and means for generating axial oscillations. According to the invention, said second meshing member (17) is translationally mobile with respect to said supporting structure along the axis (A), said means of generating axial oscillations comprising an electromechanical actuator (20) mounted in a fixed frame of reference connected with said supporting structure, able to be coupled axially to said second meshing member (17) to cause it to oscillate translationally so as to superpose an axial oscillation component on said feed movement.The invention relates to a machining device comprising a supporting structure, a transmission shaft (3) and a drive mechanism (1) comprising a first meshing member (13) able to drive the rotation of said shaft about the axis (A) thereof, a second meshing member (17) in a helicoidal connection with said shaft in order to drive the translational movement of said shaft along the axis thereof in a feed movement, dependent on the relative rotational velocity of said first and second meshing members, and means for generating axial oscillations. According to the invention, said second meshing member (17) is translationally mobile with respect to said supporting structure along the axis (A), said means of generating axial oscillations comprising an electromechanical actuator (20) mounted in a fixed frame of reference connected with said supporting structure, able to be coupled axially to said second meshing member (17) to cause it to oscillate translationally so as to superpose an axial oscillation component on said feed movement

Outils de perçage à deux moteurs coaxiaux

La présente invention concerne le domaine de l’usinage par enlèvement de matière. L’invention a ainsi pour objet une machine d’usinage et, plus particulièrement, une machine de perçage ou de fraisage. La machine à la particularité d’intégrer deux moteurs électriques destinés à contrôler les mouvements d’avance et de rotation d’un outil, tout en permettant une action d’assistance vibratoire, particulièrement utile pour le perçage de matériaux difficiles à usiner.La présente invention concerne le domaine de l’usinage par enlèvement de matière. L’invention a ainsi pour objet une machine d’usinage et, plus particulièrement, une machine de perçage ou de fraisage. La machine à la particularité d’intégrer deux moteurs électriques destinés à contrôler les mouvements d’avance et de rotation d’un outil, tout en permettant une action d’assistance vibratoire, particulièrement utile pour le perçage de matériaux difficiles à usiner

Repairing triangle meshes built from scanned point cloud

International audienceThe Reverse Engineering process consists of a succession of operations that aim at creating a digital representation of a physical model. The reconstructed geometric model is often a triangle mesh built from a point cloud acquired with a scanner. Depending on both the object complexity and the scanning process, some areas of the object outer surface may never be accessible, thus inducing some deficiencies in the point cloud and, as a consequence, some holes in the resulting mesh. This is simply not acceptable in an integrated design process where the geometric models are often shared between the various applications (e.g. design, simulation, manufacturing). In this paper, we propose a complete toolbox to fill in these undesirable holes. The hole contour is first cleaned to remove badly-shaped triangles that are due to the scanner noise. A topological grid is then inserted and deformed to satisfy blending conditions with the surrounding mesh. In our approach, the shape of the inserted mesh results from the minimization of a quadratic function based on a linear mechanical model that is used to approximate the curvature variation between the inner and surrounding meshes. Additional geometric constraints can also be specified to further shape the inserted mesh. The proposed approach is illustrated with some examples coming from our prototype software

Repairing triangle meshes built from scanned point cloud

International audienceThe Reverse Engineering process consists of a succession of operations that aim at creating a digital representation of a physical model. The reconstructed geometric model is often a triangle mesh built from a point cloud acquired with a scanner. Depending on both the object complexity and the scanning process, some areas of the object outer surface may never be accessible, thus inducing some deficiencies in the point cloud and, as a consequence, some holes in the resulting mesh. This is simply not acceptable in an integrated design process where the geometric models are often shared between the various applications (e.g. design, simulation, manufacturing). In this paper, we propose a complete toolbox to fill in these undesirable holes. The hole contour is first cleaned to remove badly-shaped triangles that are due to the scanner noise. A topological grid is then inserted and deformed to satisfy blending conditions with the surrounding mesh. In our approach, the shape of the inserted mesh results from the minimization of a quadratic function based on a linear mechanical model that is used to approximate the curvature variation between the inner and surrounding meshes. Additional geometric constraints can also be specified to further shape the inserted mesh. The proposed approach is illustrated with some examples coming from our prototype software

Improving the Dynamic Accuracy of Elastic Industrial Robot Joint by Algebraic Identification Approach

International audienceIn this paper, an improvement of the dynamic accuracy of a flexible robot joint is addressed. Based on the observation of the measured axis deformation, a simplified elastic joint model is deduced. In the first step, the non-linear model component's is analyzed and identified in the cases of the gravity bias and the friction term. In the second step, a non asymptotically algebraic fast identification of the oscillatory behavior of the robot axis is introduced. Finally, the performances of the identification approach are exploited in order to improve the dynamic accuracy of a flexible robot axis. This is done experimentally by the combination of the adaptation of the jerk time profile to reduce the end-point vibration and the model-based precompensation of the end-point tracking error

Machining Method and Device

To improve machining quality and performances by material removal, an active chip breaker is proposed, in order to fragment the chips while machining.To improve machining quality and performances by material removal, an active chip breaker is proposed, in order to fragment the chips while machining