Rapid generating method of numerical control machining tool path of product triangular Bezier curved surface model

Abstract

The invention relates to a rapid generating method of a numerical control machining tool path of a product triangular Bezier curved surface model, belonging to the field of computer-aided manufacture. The method comprises the following steps of: constructing the dynamic space index structure of a triangular Bezier curved surface by adopting a R*S tree; rapidly acquiring a set of triangular Bezier patches crossed with the cross section of a tool path on the basis of the structure; adaptively dispersing the triangular Bezier curved surface into a triangular grid according to a set precision threshold value, and crossing the cross section of the tool path with the dispersed triangular grid to acquire an intersection line; further iterating and calculating near curved surface points of various endpoints of the intersection line on the triangular Bezier curved surface; and with the near curved surface points as tool contacts, biasing along the normal direction of the curved surface where the near curve surface points are to acquire tool location points and processing interference points; and sequentially connecting the tool location points to generate the triangular Bezier curved surface suitable for the numerical control machining tool path of a ball tool. The method can be used for accurately acquiring the near curved surface points corresponding to the intersection line endpoints through iterative computations and processing the interference points to effectively ensure the generation accuracy of the numerical control machining tool path.

Description

technical field [0001] The invention provides a method for rapidly generating a tool track for numerically controlled machining of a triangular Bézier surface model of a product, belonging to the field of computer-aided manufacturing. Background technique [0002] In product reverse engineering, the triangular Bézier surface can effectively solve the surface reconstruction problem of 3D scattered point cloud data in reverse engineering, and has the characteristics of flexible structure and strong adaptability. At present, the digital model of the product represented by the triangular Bézier surface cannot be compatible with the mainstream CAD / CAM system, and it is difficult to perform CNC machining. Research on the generation method of NC toolpath on triangular Bézier surface, and directly generate NC toolpath through triangular Bézier surface, is of great significance for solving the problem of NC machining of products based on triangular Bézier surface in reverse engineeri...

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Problems solved by technology

[0003] Searching the prior art documents found that Xiao Yaoxian et al. published the paper "CNC Programming for Rough Machining of Triangular Bézier Surfaces" in the academic journal "Journal of Computer-Aided Design and Graphics" 2001, 13 (7), P631-635. The iterative intersection method obtains the intersection line of the section plane of the tool path and the curved surface, and then offsets to generate the finishing tool path, and performs uniform layering of variable depth of cut or equal depth of cut for the blank, and on this basis obtains the triangular Bézier surface rough machining tool path , the efficiency and accuracy of tool path generation mainly depend on the intersection efficiency and calculation accuracy of the curved surface and the tool path section plane. When generating the finishing line cutting tool path, the boundary point calculation is cumbersome and unstable, and the tool path generation efficiency is low.

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