METHOD FOR CALIBRATING COORDINATE SYSTEM IN WORKING ZONE OF COORDINATE MEASURING MACHINE Russian patent published in 2001 - IPC

FIELD: measurement technology; precision inspection (calibration) of optical coordinate measuring machines. SUBSTANCE: method involves measuring geometrical parameters of machine-structure base members in their relative position by means of double-ball standard mounted on machine table. Fastening device enables mounting first ball of standard in fixed position relative to machine table and second ball, for displacement depending on variations in spindle direction. Geometrical parameters are calculated using data obtained as follows. Standard is locked in position relative to machine table and coordinates of points on second-ball surface are measured. Then direction of standard is changed to give access to first ball and coordinates of points on second-ball are measured. Position of device that secures standard on machine table or positioning of standard in device is changed several times. Device implementing method for calibrating coordinate system in working zone of coordinate measuring machine has two balls rigidly fixed together by means of spindle made of material possessing low coefficient of linear expansion and seat for receiving one of balls; in addition, it is provided with standard fixture incorporating base used for its locking on machine table and rigidly coupled with seat receiving one of balls, as well as mandrel coupled with base for setting spindle carrying second ball in different positions. EFFECT: improved measurement accuracy. 3 cl, 2 dwg