Multi-constrained numerical control machining trajectory generation method for triangular mesh model

Abstract

The invention provides a multi-constrained numerical control machining trajectory generation method for a triangular mesh model. The method comprises the following steps: after reading a three-grid model and establishing topology information, performing adaptive mesh subdivision with processing bandwidth as a constraint; using a certain unmarked vertex on the surface of the subdivided mesh as an initial point of trajectory, calculating selective measure indexes of respective unmarked vertices in the current cutter contact first-order field, and using the vertex with the largest value as the next cutter contact, wherein the selective measure index is the weighted sum of the maximum feed speed, machining bandwidth, and optimal tooling direction weight of the current cutter contact to respective candidate point directions; marking all the selected cutter contacts and the cutter contacts within the tooling bandwidth range, ending the trajectory when the first-order neighborhood of a certain cutter contact has no unmarked points; and repeatedly generating the next trajectory until all vertices of the grid are marked. The method can effectively generate and satisfy the constraints such as machine tool kinematics and geometric machining precision by complex triangular patch models.

Description

technical field [0001] The invention relates to the technical field of CAM, in particular to a method for generating a multi-constraint numerical control machining trajectory of a triangular mesh model. Background technique [0002] When planning the tool path of the triangular mesh model, the traditional methods such as the method of equal residual height, the method of isoparameter line and the method of section plane are mostly based on the local geometric information of the surface and ignore the kinematic characteristics of the machine tool. Due to the influence of point trajectory generation, in actual processing, the machine tool often runs at a constant feed speed. When performing five-axis CNC machining, even if the machine tool is at a constant feed rate, when the local curvature of the workpiece changes drastically and the shape changes greatly during the machining process, the tool will produce large vibration fluctuations, and the feed of the machine tool itself...

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Problems solved by technology

In the academic paper "An efficient greedy strategy for five-axis tool path generation on dense triangular mesh" published in the academic journal "International Journal of Advanced Manufacturing Technology" 2014,74(9-12):1539-1550, Zhang K et al. The tool trajectory generation method considers the kinematic constraints of each axis of the machine tool when generating the tool contact trajectory on the triangular mesh surface, but this method is only suitable for surfaces with relatively dense and regular triangular meshes, and does not consider machining during the generation of the tool trajectory. Constraints on Geometric Precision

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