Taylor Hobson Limited

Michael Mills

Paul James Scott

Peter Seddon

Derek Roger Whittle

Roy George White

A metrological instrument determines a surface profile or form of a surface () of a workpiece () by effecting relative movement between a probe () and the surface () so that the probe follows and is displaced by changes in the surface topography. A measure of the displacement of the probe as it follows the surface is obtained by a displacement provider which may be an interferometric gauge (). Instead of making a measurement along a single measurement path over the surface (), respective measurements are made on sections (andorand) of that measurement path to obtain corresponding measurement data sets and these measurement data sets are independently positioned or aligned to a reference data set. The reference data set may be obtained by a measurement made on another section () of the measurement path (), on another measurement path () over another surface (and) of the component or on another measurement path over a surface on which the component is located. The aligned measurement data sets are then merged together to form a profile of the surface.

Metrological instrument

A measurement probe is carried by a carriage movable in a first direction to cause the measurement probe to traverse a measurement path across a surface of an object received by a support surface to provide measurement data representing variations in a second direction different from the first direction of surface features along the measurement path. The support surface is movable in a third direction different from the first and second directions. Measurement of a surface area is effected by controlling the carriage to cause the measurement probe to traverse a plurality of measurement paths across an area of the surface of an object mounted on the support surface and by controlling the support surface to move in the third direction after each measurement path traverse. Measurement data thus obtained for a reference sphere of previously known radius is used to determine the relative orientation of the first and third directions. Measurement data provided by the measurement probe may then be corrected in accordance with any error in the determined relative orientations of the first and third directions.

Movement control by a metrological instrument

A nominally cylindrical surface of a workpiece is sensed by a stylus displaceable radially of an axis of rotation of the surface relative to a support column defining a reference datum so that the stylus follows the cylindrical surface at a given height along the surface. Relative rotation of the workpiece and the stylus about the axis of rotation of the surface is effected and the displacement of the stylus used to determine information relating to the radial form of the surface at that height. These measurements are represented at different heights along the surface so as to determine its cylindrical form. The displacement of the stylus from a given position on the surface at each height before and after rotation of the stylus and workpiece through 180&deg; are measured and the resulting measurements used to compensate for any error or deviation in the reference datum.

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Leicester, United Kingdom

Michael Mills