Abstract: A series of nominally identical workpieces is received from a manufacturing process and measured on a measuring apparatus. They are received at a non-ambient temperature because of heat introduced during the manufacturing process, but they are placed on the measuring apparatus in a repeatable manner, e.g. by a robot, such that their non-ambient temperatures when measured are repeatable. One of the workpieces is measured as a reference workpiece at the non-ambient temperature, and these measurements are compared to calibrated values obtained from an external source, in order to generate an error map or error function. The error map or error function is used to correct measurements of subsequent workpieces of the series which are measured at the repeatable non-ambient temperature.

Abstract: A series of nominally identical workpieces is received from a manufacturing process and measured on a measuring apparatus. They are received at a non-ambient temperature because of heat introduced during the manufacturing process, but they are placed on the measuring apparatus in a repeatable manner, e.g. by a robot, such that their non-ambient temperatures when measured are repeatable. One of the workpieces is measured as a reference workpiece at the non-ambient temperature, and these measurements are compared to calibrated values obtained from an external source, in order to generate an error map or error function. The error map or error function is used to correct measurements of subsequent workpieces of the series which are measured at the repeatable non-ambient temperature.

Abstract: A detecting system for detecting flaws in a sample includes an illumination assembly and detecting assembly. The illumination assembly has an infra-red light source and illumination optics for directing a beam of light from the light source to a spot on or within a sample. The detection assembly has a detector for detecting light from an illuminated spot on or within a sample and detection optics for directing light from an illuminated spot on or within a sample to the detector. Such a system may be used for determining flaws in a sample such as a thermal barrier coating on a turbine blade, or a dental or other medical part. In particular the system may be used for determining flaws in a ceramic sample. A method for detecting flaws in a sample is further described.

Abstract: A method of measuring an object using a surface sensing device mounted on a coordinate positioning apparatus. The method has the steps of measuring a single surface point of a feature of the object with the surface sensing device, moving the surface sensing device along a path around the feature at a fast speed, thereby taking measurements along the path, including at the surface point, determining the difference between the measurements of the surface point and using the difference determined to apply a correction to the object or subsequent objects having the same feature.

Abstract: A method of error compensation for measurements taken using a co-ordinate positioning apparatus comprising an articulating probe head having a surface detecting device. The surface detecting device is rotated about at least one axis of the articulating probe head during measurement. The method comprises the steps of: determining the stiffness of the whole or part of the apparatus; determining one or more factors which relate to the load applied by the articulating probe head at any particular instant, and determining the measurement error at the surface sensing device caused by the load.

Abstract: Error correction of measurements of workpieces taken using a coordinate positioning apparatus in which the workpiece is mounted on a bed of the apparatus and a workpiece sensing probe is moved relative to the bed into a position sensing relationship with each workpiece and a position reading taken, and in which means are provided for measuring at least a function of the acceleration of the probe relative to the bed, the method including, in any suitable order: measuring the workpiece; determining the repeatable measurement errors from a predetermined error function, look-up table or map; measuring at least a function of the acceleration and calculating the unrepeatable measurement errors as the workpiece is measured; and combining the repeatable and non repeatable errors in steps (b) and (c) to determine the total errors; and using the total errors determined in step (d) to correct the measurements of the workpiece.

Abstract: A surface sensing device includes an articulating head adapted for attachment to the spindle of a measuring machine and having two relatively rotatable parts capable of rotation about two mutually perpendicular axes. The device additionally includes a stylus assembly having a relatively stiff hollow stylus carrier, and a relatively flexible hollow stylus. An optical transducer system is provided within the stylus assembly and comprises a fixed light source which directs a beam of light towards a stylus tip, and a retro-reflective component at the tip which reflects the beam back to a fixed detector. The arrangement is such that lateral displacement of the stylus tip when the tip is in contact with a surface can be measured directly.