Abstract: In a machine tool (1) comprising a rotating spindle (2) and a vision system (7) for acquiring images of a tool (3) mounted on the spindle, for each value (VC) of an interval (ICN) of preselected rotational speed values centered on a nominal rotational speed value (VN) of the spindle, an image acquisition period (TA) is determined, that is a multiple of the rotational period (TR) of the spindle calculated for that preselected speed value and compatible with the vision system, and, while the spindle is rotating at the nominal rotational speed, a representative couple of tool images that are temporally spaced apart from one another of the image acquisition period is obtained, in order to obtain an estimated speed value (VS), associated to the nominal speed value, by selecting that preselected speed value to which the representative couple of images that are the most similar to each other on the basis of a similarity rule corresponds.

Abstract: In a machine tool (1) comprising a rotating spindle (2) and a vision system (7) for acquiring images of a tool (3) mounted on the spindle, for each value (VC) of an interval (ICN) of preselected rotational speed values centred on a nominal rotational speed value (VN) of the spindle, an image acquisition period (TA) is determined, that is a multiple of the rotational period (TR) of the spindle calculated for that preselected speed value and compatible with the vision system, and, while the spindle is rotating at the nominal rotational speed, a representative couple of tool images that are temporally spaced apart from one another of the image acquisition period is obtained, in order to obtain an estimated speed value (VS), associated to the nominal speed value, by selecting that preselected speed value to which the representative couple of images that are the most similar to each other on the basis of a similarity rule corresponds.

Abstract: A method for positioning a tool (3) mounted on a spindle (2) of a numerical control machine tool in the visual field (20) of a visual system (7) for measuring the tool, includes a step of moving (35) the rotating spindle along an axis (Z) from a reference position (Z0) towards a target position (Zobj) defined in the visual field, and a step of acquiring images of the visual field. The stop of the spindle movement along the axis is controlled as soon as an acquired image (IM1) reveals (36) that a determined portion (13) of the tool, for instance a tip, has entered the visual field. When the stop is controlled (37), an instant position (Z1) of the spindle is acquired (38) and a distance (POS) between the tip of the tool and the target position is measured (39). On the basis of such instant position and distance, a final position (Z2) is calculated (40), and the spindle is brought (42) to such final position.