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Ball end milling 3D surface topography a b s t r a c tIn the field of free-form machining, CAM software offers various modes of tool-path generation, depending on the geometry of the surface to be machined. Manufactured surface quality results from the choice of machining strategy and machining parameters. The objective of this paper is to provide a 3D surface roughness parameter that formalizes the relative influence of both machining parameters and surface requirements. This roughness parameter is deduced from simulations of the 3D surface topography obtained after three-axis machining using a ball end cutter tool. Following a state-of-the-art assessment of surface roughness characterization, this paper will present the model generating these simulations before proceeding with an experimental verification campaign of the pattern left on the machined surface. An analysis of the patterns obtained for various sets of machining parameters serves to highlight those that influence 3D surface topography. The 3D surface roughness parameter is therefore defined according to both an influential machining strategy parameter and the surface description. An illustration will be proposed in the article's final section of an industrial case for which the 3D parameter has been used to determine the machining parameters that lead to the expected level of surface roughness.

Surface roughness measurements are often required to validate a machining process. However, when using a 3D surface roughness measuring instruments it is usually necessary to remove the part from the machine tool between two operations, potentially introducing systematic errors. Furthermore, surface roughness measuring instruments are not suited for measuring heavy and large parts such as stamping dies. This paper presents a method to measure the surface topography of a part in-situ, i.e. directly on the machine tool without removing the part. After introducing the sensor technology and the data acquisition chain, the effects of geometric imperfections of the machine tool and compensation for thermal effects on the measurement results are discussed.An application of the method is then presented to assess a finishing process on a five-axis machining centre including milling and polishing operations.

A mesh-based framework is developed by extending global stereocorrelation techniques to faceted surfaces with three-noded elements. A two-step self-calibration procedure is followed to determine the projection matrices of the stereo-rig and to update the nominal surface model to match the surface of interest. To prove the feasibility of mesh-based stereocorrelation, two different test parts are analyzed with the present techniques and compared to already validated optical procedures. Keywords Calibration • DIC • finite element discretization • photogrammetry • stereocorrelation 1 Introduction Geometries of manufactured parts are designed to fulfil functional requirements such as assembly constraints and fatigue life. It is therefore essential to directly control the manufacturing process.

International audienceA strong correlation (R² >0.96) is found between machined surfaces and their fatigue limits. In a larger study, the four- point bending fatigue limit was determined on steel specimens milled with two different conditions, in two directions, with and without residual stresses relieved. Curvature analysis is shown here, based on Heron's formula, as a function of scale and position, on profiles extracted parallel to the direction of maximum tensile stress, from areal texture measurements. Several combinations of parameters are regressed linearly with the fatigue limits over a range of scales. The strongest correlations are found with the mean curvature plus two standard deviations, at a scale of 610μm. The correlation varies smoothly, although not monotonously, with respect to decreasing scale, with R² falling to zero at 100μm

Digitizing systems are widely used in industry for applications such as Reverse Engineering or inspection. Given the diversity of solutions, the selection of the most appropriate systems for an application has become a challenging task. To be efficient, system selection must rely on a knowledge base of the digitizing system performance with regard to the given application. Within this context, this paper aims at presenting how a knowledge database of qualified digitizing systems can be established according to ability and quality criteria. The best system is afterwards obtained by optimizing a cost function built as the weighting sum of the criteria, weighting depending on the considered application. ___________________________________________________________________________

Managing macro and micro geometry of surfaces during manufacturing processes is a key factor for their following uses. Indeed micro-geometry and surface topography are directly linked to the performances of functions (contact, friction, lubrication, etc.) by texture parameters to ensure the desired local geometry. Common models for simulation of surface topography are based on ideal geometry of the machining tool and cannot represent surface defects. The actual prediction and simulation of defects is one step forward in a competitive context. In this paper, the realistic model proposed aims to simulate and predict as finely as possible local defects of machined surfaces taking into account the actual edge geometry of the cutting tool. The combined use of the machining kinematics and of the measured geometry of the cutting edges leads to the representation of the geometrical envelope of the surface using a Zbuffer technique. Simulation assessment is carried out by the analysis of 3D surface topography parameters such as surface complexity and relative area, and by a comparison of simulation results to an experimental case of study.

Within the context of 5-axis free-form machining, CAM software offers various ways of toolpath generation, depending on the geometry of the surface to be machined. Therefore, as the manufactured surface quality results from the choice of the machining strategy and machining parameters, the prediction of surface roughness in function of the machining conditions is an important issue in 5-axis machining. The objective of this paper is to propose a simulation model of material removal in 5-axis based on the N-buffer method and integrating the Inverse Kinematics Transformation. The tooth track is linked with the velocity giving the surface topography resulting from actual machining conditions. The model is assessed thanks to a series of sweeping over planes according to various tool axis orientations and cutting conditions. 3D surface topography analyses are performed through the new areal surface roughness parameters proposed by recent standards.