The research work reported in this paper focuses on introduces a fully STEP-compliant CNC by putting forward an interpolation algorithm for Non Uniform Rational Basic spline (NURBS) curve system for rough milling tool paths with an aim to solve the problems faced by the current CNC systems. The most important components used in aerospace, ships, and automobiles are designed with free form surfaces. An impeller is one of the most important components that are difficult to machine because of its twisted blades. The research is based on the premise that a STEP-NC program can document Dzgenericdz manufacturing information for an impeller. This way, a STEP-NC program can be made machine-independent and has an advantage over the conventional G-code based NC program that is always generated for a specific CNC machine. Rough machining is recognized as the most crucial procedure influencing machining efficiency and is critical for the finishing process. A key feature of the system is the use of STEPNC data model (ISO 14649-10: 2003; ISO 10303-238, 238: 2003), which enables more design information (e.g. geometry, workpiece information and tolerances) to be incorporated both prior to and during machining processes. The relevant algorithm for the curve was simulated in CAM software. The results have shown that the algorithm for rough milling is feasible and effective.

The research work reported in this paper focuses on introduces a fully STEP-compliant CNC by putting forward an interpolation algorithm for Non Uniform Rational Basic spline (NURBS) curve system for rough milling tool paths with an aim to solve the problems faced by the current CNC systems. The most important components used in aerospace, ships, and automobiles are designed with free form surfaces. An impeller is one of the most important components that are difficult to machine because of its twisted blades. The research is based on the premise that a STEP-NC program can document Dzgenericdz manufacturing information for an impeller. This way, a STEP-NC program can be made machine-independent and has an advantage over the conventional G-code based NC program that is always generated for a specific CNC machine. Rough machining is recognized as the most crucial procedure influencing machining efficiency and is critical for the finishing process. A key feature of the system is the use of STEPNC data model (ISO 14649-10: 2003; ISO 10303-238, 238: 2003), which enables more design information (e.g. geometry, workpiece information and tolerances) to be incorporated both prior to and during machining processes. The relevant algorithm for the curve was simulated in CAM software. The results have shown that the algorithm for rough milling is feasible and effective.

L’assemblage des plaques stratifiées ou des structures hybrides  composites/métalliques est un passage essentiel dans la réalisation des structures aéronautiques et aérospatiales. Il est alors nécessaire d’effectuer des opérations de perçage dans les plaques stratifiées. L’arrangement des fibres et leur orientation permettent de modifier les propriétés mécaniques du pli. Le concepteur peut ainsi modifier à volonté la résistance mécanique des plaques stratifiées en jouant sur l’orientation des fibres et la séquence d’empilement. Il nous paraît indispensable de prendre en compte l’effet des trous et l’orientation des fibres sur l’ensemble des mécanismes de ruine. Dans ce travail nous avons mis en évidence l’effet de l’orientation des fibres dans chaque pli et le choix de la séquence d’empilement sur la résistance à la rupture des plaques stratifiées multitrous en matériau composite carbone/époxyde sollicitées en traction.

his paper presents a combined experimental and theoretical investigation and proposes a mechanical load modeling of a multidirectional layer CFRP drilling to avoid fibers delamination by a better choice of their orientations. A first step consists in working with unidirectional CFRP to correlate cutting mode (opening, shear and bending) with force level depending on the angular tool position. The discretisation of the cutting edge is employed to know the exact contribution of each elementary part of the edge, resulting in a complete drill operation modeling (tip penetration, full engagement and exit). A second step consists in using this unidirectional approach to model a multidirectional layer CFRP drilling. In this case, layers are cut simultaneously which induce brutal mechanical load variation. A summation method is used to estimate the force level depending on fiber arrangement. Optimal orientation combinations are underlined by this approach, in order to improve the CFRP design, by considering the manufacturing concerns.

The machining of the complex forms is a characteristic of moulds and matrices manufacturing. Owing to the fact that these forms became increasingly complicated, the production of moulds and matrices require tolerances which are particularly severe. One of the principal objectives to be reached is the precision of machining and the improvement of the micro geometrical state of machined surfaces, for the minimization of polishing operations after machining which still necessary to obtain a good finished part, which is required by the car industry and the aeronautic industry. To reach these goals, it is important to choose a tool which fulfils the requirements of a machining which could be carried out in various orientations. This will make possible the machining of complex forms by using a milling machine with several axes. Among the tools allowing the realization of these complex forms, there is the ball-end mill. The goal of this work is to study the geometry of the mill's spherical part, in order to determine the contact zones between the part of complex form and the tool which is following a trajectory in space.