Abstract: A method for measuring the axial runout of a plane surface (22) of a workpiece (2) with respect to an axis of rotation (6) by means of a linear image sensor (19), in which a first optical scanning of the non-rotating workpiece is performed by translating the sensor relative to the workpiece along a direction (Z) parallel to the axis of rotation to obtain a first light intensity trend (I1) of a pixel (23) as the relative position between the workpiece and the sensor varies, and a relative position (ZR) of plane surface is determined as a function of the first light intensity trend. A second optical scanning of the workpiece is performed in the relative position of the plane surface while the workpiece rotates with respect to the axis for obtaining a second light intensity trend (I2) of the pixel as the angular position (?) of the workpiece varies.

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: Methods and apparatuses are used for optically measuring by interferometry the thickness (T) of an object (2) such as a slice of semiconductor material. Readings of the object thickness by optical interferometry are carried out, rough thickness values (RTW) are obtained and frequencies, indicating how often the rough thickness values occur, are evaluated. A limited set of adjacent rough thickness values whose frequency integration or summation represents an absolute maximum is identified, and the actual value of the thickness of the object is determined as a function of the rough thickness values belonging to said limited set of values. The rough thickness values can be divided up into classes (C) with corresponding frequencies (F), and in this case, a preponderant group (Gmax) of thickness classes is identified as the above-mentioned limited set of adjacent rough thickness.

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: Methods and apparatuses are used for optically measuring by interferometry the thickness (T) of an object (2) such as a slice of semiconductor material. Readings of the object thickness by optical interferometry are carried out, rough thickness values (RTW) are obtained and frequencies, indicating how often the rough thickness values occur, are evaluated. A limited set of adjacent rough thickness values whose frequency integration or summation represents an absolute maximum is identified, and the actual value of the thickness of the object is determined as a function of the rough thickness values belonging to said limited set of values. The rough thickness values can be divided up into classes (C) with corresponding frequencies (F), and in this case, a preponderant group (Gmax) of thickness classes is identified as the above-mentioned limited set of adjacent rough thickness.

Abstract: An apparatus for balancing a rotating body, in particular the grinding wheel of a grinding machine, comprises an assembly secured to the grinding wheel and rotating with it, with masses having an adjustable arrangement, electrical motors for controlling adjusting movements of the masses, and electrical circuits with a microprocessor unit. A transceiver terminal between a control unit and the rotating assembly provides a first contactless transmission channel for inductively coupling a fixed power source to the rotating parts, and a second contactless transmission channel for transmitting information in both directions. The second transmission channel may comprise optoelectronic devices.