A simple method for invalid loops removal of planar offset curves

Lai, Yu‐Shu; Wu, James Shih Shyn; Hung, Jui Pin; Chen, Jian Horng

doi:10.1007/s00170-004-2318-x

Cited by 17 publications

(3 citation statements)

References 28 publications

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“…With PWID, invalid loops can be removed in linear time. Lai et al [11] proposed a forward locus tracing method (FLTM) for invalid loops removal. The FLTM transforms 2D transversal intersection problems into 1D interval identification.…”

Section: Traditional Offset Methodsmentioning

confidence: 99%

Smooth contour-parallel tool path generation for high-speed machining through a dual offset procedure

Lin

Shen

et al. 2015

Int J Adv Manuf Technol

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In generating a contour-parallel tool path, traditional offset methods usually offer an arc rounding option for superior sharp corners. For the inferior ones, however, they are left untreated. The inferior sharp corners are harmful to high-speed machining (HSM). They should be dealt with when they emerge for the first time; otherwise, they will be further inherited by the offset successors. In this paper, we presented a dual offset procedure to round the inferior sharp corners. For a given path, literally, the procedure conducts two offsets: at first, the path is offset inwards, generating an intermediate curve; then, this curve is further offset outwards, outputting the dual offset curve. The dual offset curve is guaranteed to be smooth. It is used to replace the original path. One side effect of this procedure is that many uncut regions will be left in the corner areas. These uncut regions are detected through a Boolean operation and removed by smooth clearup tool paths. Finally, the dual offset and clear-up tool paths are connected with a set of linking arcs. The proposed smooth tool path generation method is implemented and verified by several examples. Comparative cutting simulations show that this method has a potential to improve the machining efficiency in terms of HSM with nearly a zero cost.

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Section: Traditional Offset Methodsmentioning

confidence: 99%

Smooth contour-parallel tool path generation for high-speed machining through a dual offset procedure

Lin

Shen

et al. 2015

Int J Adv Manuf Technol

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“…9 shown. So far, contour offset algorithms are roughly divided into four categories: Voronoi diagram [12][13][14], level set [15][16][17], edge offset [18][19][20], and vertex offset [21][22][23]. Although contour offset is a simple problem and there are many algorithms to implement it, it is not easy to calculate the contour offset quickly and accurately.…”

Section: Layered Cutting and Contour Offsetmentioning

confidence: 99%

Process information transferring for cutting paths in laser manufacturing

Lin²,

Liu³

et al. 2022

Int J Adv Manuf Technol

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In laser manufacturing, the cutting parameters, such as laser power, cutting speed, assist gas pressure and stand off distance, have a great in uence on the quality of the machined parts. To ensure the quality of the machined part, the process information (cutting parameters) need to be manually assigned and adjusted according to the different geometry characters of the part edges, like are and line segment. The part contours are then used for generating the laser cutting paths, leaving the process information behand. Quickly and accurately transferring the process information to the corresponding cutting paths is not an easy task. In this paper, an algorithm is proposed for this task. The proposed algorithm passes information by the points in the cutting paths. First, all part edges containing process information are offset to generate closed contours. Then, whether the points in the cutting paths are included in the closed contours are judged and marked. Finally, the information as NC codes through the adjacent points in the cutting paths is outputted. To simplify the computation work, a fast approach is also proposed to determine whether the point cloud is contained in a closed contour. The feasibility and computational e ciency of the proposed algorithms are veri ed by examples, and the actual cutting comparison veri es the superiority of the proposed algorithm by cutting details of machined parts.

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“…On this plane, the inner and outer boundaries of the blank are selected as the initial drive curves for curve offsetting. The developed tool path method adopts pair-wise offset (PWO) algorithm 25–28 to generate the planar guide curves and improves further its performance using topology relations of mesh.…”

Section: Tool Path Generationmentioning

confidence: 99%

Contour-parallel tool path generation for three-axis mesh surface machining based on one-step inverse forming

Wang

Zhang

et al. 2013

Proceedings of the Institution of Mechanical Engineers, Part B:

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Recently, mesh surfaces have become the focus of considerable interest due to its simplicity for data exchange and geometric computation. However, for mesh surface machining, there are few tool path planning strategies but iso-planar method. In this article, a contour-parallel tool path method is presented for machining complicated mesh surfaces with holes or islands by introducing a so-called one-step inverse approach based on physical plastic deformation of metal materials. By rapidly simulating for the inverse forming process of sheet metal of auto-body panels, the machined surfaces are flattened into its initial flat blank on which the cutter contact points are calculated by iteratively offsetting the inner and outer contours of the blank. Then, using the mapping from the machined surfaces to the blank as a guide, the planar offset curves without self-intersection are inversely mapped onto the original mesh surfaces, forming the final contour-parallel tool paths. Benefiting the flattening method based on one-step inverse approach, the task of generating tool paths is reduced from a physical surface to a plane so that geometric computation of tool path generation is greatly simplified, especially for self-intersection elimination in offset curves. Moreover, a new data structure of offset curve is also introduced, which is used to effectively compute the self-intersections. The proposed method has been tested on several sample surfaces, and the experimental results show that the proposed method can deal with complicated mesh surfaces with holes or islands and is also more efficient compared with the traditional methods.

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A simple method for invalid loops removal of planar offset curves

Cited by 17 publications

References 28 publications

Smooth contour-parallel tool path generation for high-speed machining through a dual offset procedure

Smooth contour-parallel tool path generation for high-speed machining through a dual offset procedure

Process information transferring for cutting paths in laser manufacturing

Contour-parallel tool path generation for three-axis mesh surface machining based on one-step inverse forming

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