A real-time error correction system for spindle errors

Abstract

A methodology for machining of near-perfect bores on mild steel workpieces using an error correction system attached to a conventional, preloaded ball bearing machine tool spindle is described. The approach detects machine tool errors in real-time by using a laser-based sensor, models the errors as a background computation and uses the model to compensate, in real-time, for the deterministic errors. The hardware developed to implement the methodology scans the workpiece surface after matching with a spindle-mounted probe. If the model-based machine tool errors are subtracted from the scanned signal, and the remaining error is modeled, then an in-situ bore measurement is effectively made. This approach avoids the axis locating problem intrinsic with use of a separate measuring machine. The machine tool errors are modeled as deviations from all ideal cylinder in space. With respect to the machine tool coordinates, the model parameters include axis orientation, diameter, and cylindricity.<>