Renishaw Plc

Metrology Software Products Limited

Peter Russell Hammond

Anthony Brown

Geoffrey McFarland

Kevyn Barry Jonas

Christopher Leonard Copper

A calibration device for a machine tool is described that includes a base attachable to a machine tool and a calibration artefact, such as a sphere of known radius. A deflection mechanism attaches the calibration artefact to the base and allows movement of the calibration artefact relative to the base when an external force is applied to the calibration artefact. The deflection mechanism also maintains the calibration artefact in a defined rest position relative to the base in the absence of an applied external force. A sensor is provided for sensing the extent of movement of the calibration artefact relative to the base. A method of using the device with a reference tool to accurately determine a position of a calibration artefact is also described.

Calibration device and method

An error correction method for coordinate positioning apparatus is described. The method comprises (i) taking a first data set comprising one or more first data values, each first data value describing a position on the surface of a first object, (ii) taking a second data set comprising one or more second data values, each second data value describing a position on the surface of the first object, and (iii) calculating an error map comprising one or more error values, each error value describing a positional difference between the surface as described by the first data set and the surface as described by the second data set. The surface normal of the first object is known at each position described by each first data value and step (iii) comprises calculating each error value by determining the positional difference substantially in the direction of the known surface normal.

Measurement method and apparatus

Apparatus and method for fitting a workpiece to geometric design data of a workpiece. Nominal data points are selected from the geometric design data. Command codes are created to generate measured data points. The measurement data points have associated nominal measurement points which are used to fit the workpiece to the geometric design data. The apparatus and method may also be used to determine whether a workpiece is within tolerance and for process control.

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Warkworth, United Kingdom

Peter Russell Hammond