Off-line compensation method for contour error of machining path of four-axis lathe

Abstract

The invention provides an off-line compensation method for the contour error of the machining path of a four-axis lathe, which belongs to the field of contour error compensation of numerical control machine tool processing. The invention relates to the off-line compensation method for the processing path contour error, and the machining precision of the closed closed-loop four-axis numerical control lathe is improved. The method uses an initial turning code to generate a theoretical cutter location point and a theoretical tool axis vector. A four-axis lathe Jacobian matrix is constructed. Theactual speed of a feed axis is calculated offline, so as to estimate the follow-up error of the feed axis of the lathe. An actual cutter location point and an actual tool axis vector are calculated. Three non-uniform rational B-spline curves are used to fit the theoretical cutter location point and a tool axis mark point. A tangential error inverse method is used to estimate the foot point of theactual cutter location point to a theoretical cutter location point curve. The contour error of the cutter location point and the contour error of the tool axis vector are calculated. Finally, the follow-up error of the feed axis is pre-compensated. The method can realize the pre-compensation of the contour error of the closed closed-loop four-axis numerical control lathe, and has the advantages of convenient implementation and obvious effect.

Description

technical field [0001] The invention belongs to the field of contour error compensation for CNC lathe machining, and relates to an off-line compensation method for machining track contour errors of a four-axis lathe. Background technique [0002] Surface parts with complex surface structures are more and more widely used in aerospace, energy and power fields, and their machining accuracy directly affects the service performance of high-end equipment in related fields. Complex surface parts are often processed by multi-axis CNC lathes with rotating axes B-axis and C-axis. The rotation of the B-axis enables the tool to achieve more complex machining trajectory movements. Compared with machining errors caused by lathe geometric errors and thermal deformation, the influence of lathe dynamic characteristics on lathe machining accuracy is more significant. Due to the servo lag and dynamic mismatch of the CNC system, each feed axis will produce a follow-up error and then induce a ...

AI Technical Summary

Problems solved by technology

This method aims at the machining trajectory contour error caused by the servo lag and dynamic mismatch of the four-axis lathe, and uses the initial turning processing code to calculate the actual feed speed of the lathe feed axis and the follow-up error of the feed axis offline to realize the machining trajectory contour error Prediction and offline compensation, effectively improving the contour accuracy of the turning trajectory of complex curved surface parts

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