Method of error compensation in a coordinate measuring machine

Abstract

A method of calibrating an articulating probe head comprising the steps of measuring an artefact of known dimensions with the workpiece sensing probe mounted on the articulating probe head, in which the articulating probe head is unlocked. An error functional map is generated corresponding to the difference between the measured and known dimensions of the artefact. Subsequent workpieces are measured with the articulating probe head unlocked and the corresponding correction applied. The true dimensions of the artefact may be determined by measuring it with a probe mounted on an articulating probe head in which the axes of the articulating probe head are locked. A mechanical lock is provided to lock the axes of the articulating probe head.

Description

technical field

[0001] The invention relates to a method for measuring the size of a workpiece by using an articulated probe installed on a coordinate positioning device. Coordinate positioning devices include, for example, coordinate measuring machines (CMMs), machine tools, manual coordinate measuring arms, and inspection robots. Background technique

[0002] When a workpiece has been produced, it is often customary to place the workpiece for inspection on a coordinate measuring machine (CMM) having a sleeve on which a probe is mounted, within the working volume of the instrument, The probe can be driven in three orthogonal directions X, Y and Z.

[0003] The CMM can establish an error correspondence using, for example, a laser interferometer that can accurately measure a part at low speed.

[0004] When measuring workpieces at high speeds, dynamic errors occur as the instrument accelerates. Our prior US Patent No. 4,991,304 discloses a method of calibrating for these d...

Images