An efficient surface–surface intersection algorithm based on geometry characteristics

Li, Xueyi; Jiang, Hong; Chen, Song; Wang, Xiaochun

doi:10.1016/j.cag.2004.04.008

Cited by 17 publications

(10 citation statements)

References 20 publications

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“…The subsequent step is the slicing procedure of every single item in the list. To perform such operation a surface-to-surface intersection operation must be carried out (an algorithm could be found for example in [25]). The intersection operation is performed between a plane with the normal oriented according to the building direction, i.e.…”

Section: Proposed Cam Software: the Feature Recognition Modulementioning

confidence: 99%

Feature based three axes computer aided manufacturing software for wire arc additive manufacturing dedicated to thin walled components

Venturini

Montevecchi

Bandini

et al. 2018

Additive Manufacturing

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WAAM (Wire-Arc-Additive-Manufacturing) is a metal additive manufacturing process using arc welding to create large components with high deposition rate. The workpiece quality and the process productivity are strongly dependent both on the process parameters (wire feed speed, voltage and current) and on the selected deposition path. Currently, the CAM (Computer-Aided-Manufacturing) software dedicated to WAAM rely on a multi-pass strategy to create the component layers, i.e. each layer is built overlapping multiple welding passes. However, since WAAM can create wide layers, a single pass strategy can improve the process efficiency when dealing with thin walled components. This paper proposes CAM software dedicated to WAAM, using a single pass strategy. The proposed solution uses a midsurface representation of the workpiece as input, to generate the deposition toolpath. A feature recognition module is proposed, to identify the critical features of the part, such as free end walls, t-crossings, direct-crossings and isolated tubulars. A specific strategy is developed and proposed for each one of the selected features, with the aim of minimizing the geometrical errors and to ensure the required machining allowances for the subsequent finishing operations. The effectiveness of the proposed strategy is verified manufacturing a test case.

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Section: Proposed Cam Software: the Feature Recognition Modulementioning

confidence: 99%

Feature based three axes computer aided manufacturing software for wire arc additive manufacturing dedicated to thin walled components

Venturini

Montevecchi

Bandini

et al. 2018

Additive Manufacturing

View full text Add to dashboard Cite

show abstract

“…The state of the art heat source model for WAAM, is represented by the Goldak double ellipsoid [24]. In this paper, an alternative model developed by the authors [25], was chosen over the traditional double ellipsoid. As in the double ellipsoid model, the proposed heat source prescribes the welding heat input as a heat generation function, but it allows to control the amount of total power delivered to the substrate and to the filler.…”

Section: Heat Source Modelingmentioning

confidence: 99%

Finite Element mesh coarsening for effective distortion prediction in Wire Arc Additive Manufacturing

Montevecchi

Venturini

Grossi

et al. 2017

Additive Manufacturing

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“…Both projection and inversion are useful for surface intersection [1], tool path generation, and collision detection in numerical control (NC) machining [2]. They are also a key issue in the inspection of manufactured objects [3].…”

Section: ½ áòøöó ù ø óòmentioning

confidence: 99%

Geometric algorithm for point projection and inversion onto Bézier surfaces

Liu

et al. 2009

Front. Comput. Sci. China

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This paper presents an accurate and efficient method for the computation of both point projection and inversion onto Bézier surfaces. First, these two problems are formulated in terms of solution of a polynomial equation with u and v variables expressed in the Bernstein basis. Then, based on subdivision of the Bézier surface and the recursive quadtree decomposition, a novel solution method is proposed. The computation of point projection is shown to be equivalent to the geometrically intuitive intersection of a surface with the u-v plane. Finally, by comparing the distances between the test point and the candidate points, the closest point is found. Examples illustrate the feasibility of this method.Keywords point projection, point inversion, Bézier surface ½ ÁÒØÖÓ Ù Ø ÓÒProjecting a test point onto a parametric surface in order to find the closest point (the point projection problem) and computing the corresponding parameter values of the projection (the point inversion problem ) are two basic problems in computational geometry, geometric modeling, computer graphics, and related topics. Both projection and inversion are useful for surface intersection [1], tool path generation, and collision detection in numerical control (NC) machining [2]. They are also a key issue in the inspection of manufactured objects [3]. For these purposes, it is important to have a computational method which is efficient and reliable to find Several algorithms which employ some variations of Newton iteration or numerical optimization have been developed to solve this problem. Mortenson [4] derived equations for different types of surface distance measure and employed the Newton-Raphson method to solve them. Limaiem and Trochu [5] proposed another approach to compute the projection of a point onto parametric curves and surfaces by constructing an auxiliary function and finding its zeros. These algorithms converge quickly, but the sensitivity of the iteration process to initial values is also well known. As an improvement, Hu and Wallner [6] developed a second-order algorithm for point projection onto curves and surfaces. It increases the robustness to the choice of initial values.This Newton-type methods have been used in CAD/CAM applications and acquired high accuracy because they are efficient (usually exhibiting quadratic convergence rates close to simple roots) and straightforward to program. Unfortunately, this is an error-prone process which often fails for points near the endpoints of the curve or the boundaries of the surface and this procedure typically requires a good initial value to ensure the convergence to the optimal root in the global scene. Such initial approximations are usually obtained by sampling the curve or surface, but this process cannot provide full assurance that all roots have been found. This lack of robustness promotes the development of efficient and reliable techniques. Piegl and Tiller [7] presented an algorithm for point projection on non-uniform rational Bsplines (NURBS) surface. It consists...

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An efficient surface–surface intersection algorithm based on geometry characteristics

Cited by 17 publications

References 20 publications

Feature based three axes computer aided manufacturing software for wire arc additive manufacturing dedicated to thin walled components

Feature based three axes computer aided manufacturing software for wire arc additive manufacturing dedicated to thin walled components

Finite Element mesh coarsening for effective distortion prediction in Wire Arc Additive Manufacturing

Geometric algorithm for point projection and inversion onto Bézier surfaces

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