摘要:
The present invention includes a method of precisely calibrating the position of a spindle (20) of a drilling apparatus (10) with respect to a worktable (14). The drilling apparatus (10) includes the control device (22), which calculates an expected relative position of the spindle (20) and the worktable (14) based upon predetermined information regarding the relative position of the spindle (20) and the worktable (14) and the controlled movement of the spindle (20) relative the worktable (14). The method includes positioning the spindle (20) in a first position with respect to the worktable (14), empirically determining the position of the first position with respect to the worktable (14) in a first direction, empirically determining the position of the first position with respect to the worktable (14) in a second direction, and comparing the expected relative position of the spindle (20) and the worktable (14) at the first position with the empirically determined relative position of the spindle (20) relative the worktable (14) in the first direction and the second direction so as to ascertain the "proper correction factor." Another aspect of the invention is a calibration device (54), including a body (66) defining an aperture and (56) an opening spaced from the aperture (56), a first differential pressure transducer (62) measuring the position of an object in the aperture (56) in a first direction, a second differential pressure transducer (64) measuring the position of an object in the aperture (56) in a second direction different from the first direction, and a third differential pressure transducer measuring the direction of an object in the opening in the first direction. Advantageously, the device (54) includes means for securing the device to a worktable (14) to prevent movement of the device in the first direction and the second direction. Preferably, this securing means comprises releasable vacuum cups (130).