Numerical control machining track smoothing method based on cutter location point addition, deletion and modification instructions

Abstract

The invention belongs to the related technical field of numerical control, and discloses a numerical control machining track smoothing method based on cutter location point addition, deletion and modification instructions. The method comprises the steps of S1, for a numerical control machining track to be processed, calculating a distance between every two adjacent cutter location points on a machining track, and when the distance between every two adjacent cutter location points is larger than a preset maximum threshold value, adding a new cutter location point between every two adjacent cutter location points till that the distance does not exceed the maximum threshold value; when the distance between the adjacent cutter location points is smaller than a preset minimum threshold value, deleting one of the cutter location points; when the distance between the adjacent cutter location points is between the preset maximum threshold value and the preset minimum threshold value, modifyingthe cutter location points; and S2, constructing constraint conditions of actual machining of the numerical control system, and judging whether each cutter location point on the machining track meetsthe constraint conditions or not; and modifying the tool location points which do not meet the requirements. In the invention, processing efficiency is not sacrificed as much as possible, and the processed cutter location point can better meet smooth and stable processing requirements.

Description

technical field [0001] The invention belongs to the technical field related to the technical field of numerical control, and more specifically relates to a method for smoothing the trajectory of numerical control machining based on the instruction of addition, deletion and modification of tool positions. Background technique [0002] During the NC machining process, the CAM system discretizes the free-form surface into small line segments, generates the corresponding processing path, and then generates the corresponding G01 code, which is then input into the NC system for interpolation processing. Because there are corners between continuous small line segments and the local irrationality of surface discreteness, when the CNC system directly processes small line segments, it will inevitably cause frequent fluctuations in acceleration and reduce the processing speed. The tool leaves redundant tool marks on the surface of the workpiece, which affects the surface finish of the ...

AI Technical Summary

Problems solved by technology

Because there are corners between continuous small line segments and the local irrationality of surface discreteness, when the CNC system directly processes small line segments, it will inevitably cause frequent fluctuations in acceleration and reduce the processing speed. The tool leaves redundant tool marks on the surface of the workpiece, which affects the surface finish of the machining result

[0003] In order to solve the problem of tool shake in the process of NC machining and improve the machining accuracy and stability, the current research on the smoothness of NC machining is mostly carried out from two aspects: interpolation and speed planning. One is to perform spline fitting interpolation from the interpolation level Complement, so that the small line segments formed by the generated interpolation points can achieve better spline fitting conditions (such as B-splines, etc.), this method often involves the forward-looking and interpolation information of the program segment. The length of the small line segment, the curvature of each interpolation point and the rate of change of the corner, etc.), after the fitting, the corresponding error calculation and re-fitting process are often carried out; the second is from the speed planning level, to develop a model that is compatible with the movement of the CNC system The advanced acceleration and deceleration algorithm makes the tool have better motion characteristics during processing. While this method improves the smoothing performance of the tool, it is likely to be accompanied by a reduction in processing efficiency and an increase in servo motion performance requirements.

The control requirements of the numerical control system are extremely high in real-time performance. Neither the calculation amount of the interpolation point fitting process nor the complexity of the algorithm related to the speed planning control should be too high. There are often irreconcilable contradictions between the reduction of servo control performance, and the cost of servo control performance improvement is very high

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