A NC Machining Trajectory Smoothing Method Based on Addition, Deletion, and Modification of Tool Points

Abstract

The invention belongs to the relevant technical field of the numerical control technology field, and discloses a numerical control machining trajectory smoothing method based on a tool position point addition, deletion and modification instruction. The method includes: S1 For the CNC machining track to be processed, calculate the distance between adjacent tool position points on the machining track, and when the distance between adjacent tool position points is greater than the preset maximum threshold, the adjacent tool position Add a new tool point between the points until the maximum threshold is not exceeded; when the distance between adjacent tool points is less than the preset minimum threshold, delete one of the tool points; when the distance between adjacent tool points When it is between the preset maximum threshold and the minimum threshold, modify the tool position points; S2 constructs the actual machining constraints of the CNC system, and judges whether each tool position point on the machining track satisfies the constraint conditions; unsatisfied tool positions Click to modify. Through the present invention, the processed tool position can better meet smooth and stable processing requirements while not sacrificing processing efficiency as much as possible.

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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