Patent ID: 8112173
Filing Date: 2012-02-07
Classification: G05B,Y02P,Y10T

Abstract:
1. A position ensuring system for correcting an error in a five-axis machine tool having, in addition to X-axis, Y-axis and Z-axis, an A-axis for pivoting of a spindle head and a C-axis for rotation of a table, thereby ensuring the position of the spindle head in oblique machining of inclined holes in a workpiece, said system comprising: an A-axis calibration system which measures a displacement angle, which is an error between a target value and a measured value of the pivot angle of the spindle head about the A-axis as the spindle head is pivoted to meet the inclination angle of an inclined hole to be machined in a workpiece, and corrects the pivot angle about the A-axis in such a manner that the displacement angle as measured with the corrected pivot angle as a target value fall within a tolerable range, before initiating machining of the workpiece, the measurement of displacement angle being carried out for all the inclined holes to be machined by execution of a measurement program prepared based on data on the shapes, including the inclination angles and the directions, of the inclined holes to be machined; a corrected data storage device which stores the corrected pivot angle about the A-axis for each of the inclined holes to be machined; and an A-axis control system which reads out the corrected pivot angle about the A-axis for each inclined hole upon executing a machining program for the workpiece by means of an NC apparatus, and uses the corrected pivot angle about the A-axis to pivot the spindle head when executing oblique machining of the inclined hole; wherein the A-axis calibration system comprises: