Abstract: A position measurement encoder including a scale and a readhead, the readhead including a sensor for sensing the scale, the sensor including a one-dimensional array of columnar pixels, configured such that the one-dimensional array of columnar pixels is divided into a plurality of rows wherein each columnar pixel has at least one individual sensing section in each row arranged to contribute to the columnar pixel's output. Each row is individually activatable so that which one or more of the individual sensing sections in the columnar pixels contribute to each columnar pixel's output can be selectively chosen and changed on a row-by-row basis.

Abstract: A coordinate positioning machine includes a plurality of drive axes, each being a rotary or linear drive axis, for positioning a platform within a working volume of the machine, and a separate linear counterbalance axis for counterbalancing the platform. With this arrangement the counterbalance axis can be substantially invariant to changes in orientation of the drive axes and can be counterbalanced by a simple counterweight. Also, an arrangement wherein the counterbalance axes and force generator are arranged so horizontal movement of the platform causes substantially no net movement of and/or no work to be done on the generator. Also, an arrangement wherein a series of counterbalance axes has at least one rotary counterbalance axis, and the generator is arranged behind or at a predetermined distance from the counterbalance axis. Also, an arrangement having a series of counterbalance axes with at most one rotary counterbalance axis between the generator and ground.

Abstract: This invention concerns a laser solidification apparatus for building objects by layerwise solidification of powder material. The apparatus including a build chamber containing a build platform, a device for depositing layers of powder material on to the build platform, an optical unit for directing a laser beam to selectively solidify areas of each powder layer and a spectrometer for detecting characteristic radiation emitted by plasma formed during solidification of the powder by the laser beam. The invention also relates to a spectrometer for detecting characteristic radiation generated by interaction of the metal with the or a further laser beam. The spectra recorded using the spectrometer may be used for feedback control during the solidification process.

Abstract: A method of generating a spatial map of sensor error data from a coordinate positioning machine including: receiving measurement data collected by measuring or tracking an artefact as it is moved by the machine along at least one machine axis; deriving error data by comparing the received measurement data with expected or ideal values for the measurement data; and generating a spatial error map from the error data, with each cell including an error representation derived from multiple sources of error within the error data.

Abstract: A method of generating a spatial map of sensor data collected during additive manufacturing, in which a plurality of layers of powder are selectively melted with an energy beam to form an object. The method includes receiving sensor data collected during additive manufacturing of an object, the sensor data including sensor values, the sensor values captured for different coordinate locations of the energy beam during the additive manufacturing of the object, and generating cell values for a corresponding cell-based spatial mapping of the sensor data. Each of the cell values is determined from a respective plurality of the sensor values extending over an area/volume comparable to an extent of the melt pool or the energy beam spot.

Abstract: A method of calibrating a coordinate positioning machine is described. The machine is controlled into a pivot pose in which a target point associated with a moveable part of the machine and a pivot point associated with a fixed part of the machine are separated from one another by a known separation. An error value for that pose is determined based on the known separation and a separation expected for that pose from the existing model parameters of the machine. The machine is controlled into a plurality of different target poses, and for each target pose a separation between the target point and the pivot point is measured and an error value for that pose is determined based on the measured separation and a separation expected for that pose from the existing model parameters.

Abstract: An articulated head for facilitating reorientation of a mounted tool, including: a first member for mounting the head on a positioning apparatus; a second member coupled to the first so its orientation relative thereto about a first axis can be changed between, and locked at predefined orientations, the members can be unlocked by separating the members along the first axis for reorientation of the second member about the first axis; a third member coupled to the second so its orientation relative thereto about a second axis can be changed between, and locked at predefined orientations, the second and third members can be unlocked by separating the members along the second axis for reorientation of the third member about the second axis, the first and second axes are not parallel; and a powered mechanism independently controlling separation of the first and second and the second and third members.

Abstract: A measurement apparatus for mounting within an enclosure of a machine is described. The apparatus includes a measurement device and a protection means for protecting the measurement device from contaminants present within the machine enclosure. The protection means is switchable between at least a first mode that protects the measurement device from contaminants and a second mode that provides less protection of the measurement device from contaminants than the first mode. A contaminant sensor is used for sensing contamination within the machine enclosure and thereby determining when the protection means can adopt the second mode. A corresponding method is also described.

Abstract: An apparatus including an encoder scale disc and a mount, the encoder scale disc including radially and/or tangentially resilient features located radially outwards of a scale configured to interact with the mount so as to locate the scale disc on the mount. The encoder scale disc may include radially resilient features which may deviate radially from the disc. A method of manufacturing an apparatus including an encoder scale disc, including mounting a disc including radially resilient features to a device, wherein the radially resilient features of the disc interact with the device to place the disc in radial compression, mounting the disc on an apparatus, wherein mounting features on the device and the apparatus interact in the same manner to place the disc in radial compression.

Abstract: An encoder apparatus including a reflective scale and a readhead. The readhead includes at least one light emitting element, at least one sensor and at least one optical device, which together with the scale form an optical system in which the optical device forms an image of an illuminated region of the reflective scale onto the sensor. The system's optical path, from the light emitting element to the sensor, passes through the optical device on its way toward and after reflection from the scale, and includes an unreflected optical path between the light emitting element and the optical device and an unreflected optical path between the optical device and the sensor.

Abstract: A method for removing noise from spectral data recorded using a spectrometer. The method includes normalising spectral data to generate normalised spectral data and applying a machine learning model to the normalised spectral data. The machine learning model is trained to remove noise from spectral data using normalised training data, wherein the spectral data is normalised based on a different scaling to the normalisation of the training data.

Abstract: A coordinate positioning machine includes a plurality of drive axes, each being a rotary or linear drive axis, for positioning a platform within a working volume of the machine, and a separate linear counterbalance axis for counterbalancing the platform. With this arrangement the counterbalance axis can be substantially invariant to changes in orientation of the drive axes and can be counterbalanced by a simple counterweight. Also, an arrangement wherein the counterbalance axes and force generator are arranged so horizontal movement of the platform causes substantially no net movement of and/or no work to be done on the generator. Also, an arrangement wherein a series of counterbalance axes has at least one rotary counterbalance axis, and the generator is arranged behind or at a predetermined distance from the counterbalance axis. Also, an arrangement having a series of counterbalance axes with at most one rotary counterbalance axis between the generator and ground.

Abstract: An optical tool measurement device for a machine tool is described. The device includes a light source for directing light towards a tool-sensing region and a sensor for detecting light from the tool-sensing region. A shutter assembly for selectively protecting the sensor from contamination is also provided. The shutter assembly is to provide a closed configuration in which the sensor is covered by the shutter assembly thereby preventing contamination of the sensor and an open configuration in which light can pass to the sensor through a first aperture of the shutter assembly. Furthermore, the shutter assembly is configured to additionally provide a constricted configuration in which light can pass to the sensor through a second aperture of the shutter assembly, the second aperture being smaller than the first aperture. In this manner, the device has enhanced resistance to contaminants, such as swarf and coolant, present in the machine tool environment.

Abstract: This invention concerns a laser solidification apparatus for building objects by layerwise solidification of powder material. The apparatus including a build chamber containing a build platform, a device for depositing layers of powder material on to the build platform, an optical unit for directing a laser beam to selectively solidify areas of each powder layer and a spectrometer for detecting characteristic radiation emitted by plasma formed during solidification of the powder by the laser beam. The invention also relates to a spectrometer for detecting characteristic radiation generated by interaction of the metal with the or a further laser beam. The spectra recorded using the spectrometer may be used for feedback control during the solidification process.

Abstract: An encoder apparatus including a readhead for reading a reflective scale located adjacent the readhead. The readhead includes a circuit board on which a sensor including one or more photodiodes for detecting light reflected from a scale located adjacent the readhead is mounted, and at least one light emitting element. The light emitting element is mounted to the circuit board via a light emitting element support structure which holds the light emitting element away from the circuit board and the sensing plane of the sensor, and at least a part of which extends over the sensor.

Abstract: A metrology apparatus including an articulated joint having: first and second bodies which can be locked together in a plurality of different angular orientations about a first axis; the first body including a prop which is actuatable by a motor between a retracted configuration at which the first and second bodies are in their locked state, and an extended configuration at which the first and second bodies are held apart by the prop along the first axis such that the first and second bodies are unlocked thereby permitting relative rotation of the first and second bodies, the prop and the second body being magnetically biased toward each other so as to magnetically retain the first and second bodies; and further including at least one supplemental bias member configured to bias the prop towards its retracted configuration.

Abstract: Selective laser solidification apparatus is described that includes a powder bed onto which a powder layer can be deposited and a gas flow unit for passing a flow of gas over the powder bed along a predefined gas flow direction. A laser scanning unit is provided for scanning a laser beam over the powder layer to selectively solidify at least part of the powder layer to form a required pattern. The required pattern is formed from a plurality of stripes or stripe segments that are formed by advancing the laser beam along the stripe or stripe segment in a stripe formation direction. The stripe formation direction is arranged so that it always at least partially opposes the predefined gas flow direction. A corresponding method is also described.

Abstract: A pallet loader for a positioning apparatus, including at least two pallet bays and at least one intermediate member, arranged such that at least two pallet bays are located on different sides of the intermediate member, such that at least one pallet can be driven i) from one pallet bay to another, and ii) from one pallet bay to a positioning apparatus, in which the apparatus includes cooperating guide features on the underside of the at least one pallet and on one or more of the intermediate member and pallet bays for guiding the pallet along a predetermined path and/or for controlling the rotational orientation of the pallet about a vertical axis, as the pallet moves across the intermediate member/pallet bay.

Abstract: A surface finish stylus is described that includes an elongate stylus shaft and a contact element protruding from the elongate shaft for contacting a surface to be measured. The contact element is deformable and the stylus shaft includes a clamp for retaining the contact element, the contact element being deformed by the clamp. The contact element may comprise a metal, such as chromium steel or nitinol. The contact element includes one or more regions of weakness to cause a required deformation when retained by the clamp. The surface finish stylus may be used with a surface finish measurement probe or the like.

Abstract: A motorised measurement arm apparatus for a machine tool includes a base for attachment to the machine tool and an arm member extending from the base for holding one or more sensors. The arm member is moveable relative to the base between a stowed position and an operative position, the operative position being defined by engagement of a mechanical stop arrangement. The apparatus also has a motor for moving the arm member relative to the base and a motor controller for energising the motor to move the arm member relative to the base. The motor controller is configured to energise the motor when the arm member is in the operative position to maintain engagement of the mechanical stop arrangement. An operative position having improved repeatability is thus obtained.