Abstract: This invention concerns an additive manufacturing apparatus for building an object by consolidating material in a layer-by-layer manner using an energy beam. The additive manufacturing apparatus comprising an optical module for steering a laser beam onto the material and for collecting light generated by an interaction of the laser beam with the material. The optical module comprises a beam splitter angled relative to an optical path shared by the laser beam and the collected light. The beam splitter separates the collected light from a path of the laser beam for directing the collected light to a detector. The optical module further comprises a corrective optical element for correcting for at least one optical aberration introduced into the collected light by the beam splitter.

Abstract: This invention concerns an additive manufacturing apparatus for building a part by selectively consolidating flowable material in a layer-by-layer process comprising a build chamber (101) for building the part, a module (105, 106) for providing a focussed energy beam for consolidating flowable material in the build chamber, a gas flow circuit for generating a gas flow through the build chamber (101). At least one filter assembly (200, 201) may be arranged in the gas flow circuit, the or each filter assembly (200, 201) having associated therewith a valve (V-4, V-8) operable to seal the gas circuit upstream from the filter assembly (200, 201) and a valve (V-5, V-9) operable to seal the gas flow circuit downstream of the filter assembly (200, 201), the arrangement allowing a filter element (E-5, E-7) of the filter assembly (200, 201) to be changed whilst maintaining a controlled atmosphere in the build chamber (101).

Abstract: A frequency tuneable laser device includes a cavity mode selector and a cavity tuning arrangement. The cavity mode selector has a frequency response with a selection feature that is alignable in frequency with a selected cavity mode of the laser device. The cavity tuning arrangement includes a plurality of reflective elements arranged in optical series, and is used to adjust the effective optical path length of the laser cavity to move the cavity modes in frequency. The laser device further includes making the cavity mode selector and the cavity tuning arrangement perform a simultaneous coordinated movement such that respective frequencies of the selection feature and the selected cavity mode vary with substantially the same dependence on a parameter characterizing the simultaneous coordinated movement. For example, a periscope with a co-rotating etalon can be used to provide mode hop free tuning of the laser device.

Abstract: A method of inspecting an artifact on a machine tool includes: scanning a probe mounted on the machine tool along the surface of the artifact to be inspected. The method involves supplying a flow of fluid at least at the point of interaction between the probe and the artifact during the scanning.

Abstract: An electro-magnetic brake which is switched between an operative braking position and an inoperative position by transient pulses of current. It is held passively in the operative and inoperative positions with little or no current. This prevents the generation of heat, which would affect the accuracy of measurements where the brake is used in dimensional measuring equipment. In one form, permanent and semi-permanent magnets are arranged in parallel, and the magnetic polarity of the arrangement is flipped by transient current pulses in a surrounding coil. A capacitor may provide a reservoir of current to activate the brake in the event of a power supply failure.

Abstract: An encoder apparatus including a scale and a readhead including a sensor including an array of sensor elements for detecting a scale signal falling on the sensor, configured such that the sensor elements' outputs that are used to determine the relative position of the scale and readhead are weighted such that the influence of the sensor elements on the determined relative position of the scale and readhead varies across the array according to a predetermined non-rectangular window function that is configured to reduce the adverse effect of undesirable frequencies in the scale signal so as to thereby reduce the encoder apparatus' sub-divisional error.

Abstract: A method of treating a movement disorder using deep brain stimulation, the method comprising the step of inserting a lead having at least one electrode into the brain of a subject, the lead being inserted along a trajectory from the occipito-temporal or occipito-parietal regions, passing laterally to the posterior horn of the lateral ventricle to contact the subthalamic nucleus, the zona incerta or the globus pallidus.

Abstract: A method of scanning an object using an analog probe mounted on a machine tool, so as to collect scanned measurement data along a nominal measurement line on the surface of the object, the analog probe having a preferred measurement range. The method includes controlling the analog probe and/or object to perform a scanning operation in accordance with a course of relative motion, the course of relative motion being configured such that, based on assumed properties of the surface of the object, the analog probe will be caused to obtain data within its preferred measuring range, as well as cause the analog probe to go outside its preferred measuring range, along the nominal measurement line on the surface of the object.

Abstract: A non-Cartesian coordinate positioning machine is provided that comprises an extendable leg assembly for positioning a component such as a measurement probe within a working volume of the machine, and a constraint member associated with the extendable leg assembly for providing a predetermined part of the extendable leg assembly with substantially a same orientation relative to gravity for a same position of the component within the working volume. In a preferred embodiment, the orientation relative to gravity is maintained substantially constant, so that a plane defined by the predetermined part is substantially aligned with gravity, as the component is moved around the working volume.

Abstract: An optical element for generating diffraction orders for an encoder apparatus, in which the optical element includes an array of diffraction features arranged such that the spacing between the centres of adjacent diffraction features varies irregularly from one pair of adjacent features to the next.

Abstract: A method of measuring at least one point on an artefact to be inspected that is located within a positioning apparatus' measurement volume, the method comprising, obtaining at least two images of the artefact obtained from different perspectives and, based on a given nominal location of a predetermined point to be measured within said positioning apparatus' measurement volume, determine the location of said predetermined point in each of the at least two images.

Abstract: An additive manufacturing apparatus and corresponding method for building an object by layerwise consolidation of material wherein the apparatus includes a build enclosure containing a build support for supporting the object during the build, a material source for providing material to selected locations for consolidation, a radiation device for generating and directing radiation to consolidate the material at the selected locations and an acoustic sensing system. The acoustic sensing system may be arranged to detect acoustic signals generated in the build enclosure by consolidation of the material with the radiation. The acoustic sensing system may be a passive acoustic sensing system arranged to detect acoustic signals generated in the build enclosure that are indicative of at least one condition of the building process and/or the object.

Abstract: A method of manufacturing an article, comprising taking an article formed in an initial state via an additive manufacturing process and performing a second manufacturing process to transform the article into a second state, which comprises mounting the article in a holding device, processing at least one first feature on the article, which comprises processing at least one set of mounting features on the article, re-mounting the article via the at least one set of mounting features, and then processing at least one second feature on the article.

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 device and method for generating scan data and/or slice data for use in an additive manufacturing process, in which an energy beam is scanned across layers of flowable material to consolidate the material in a layer-by-layer manner to build a part. The device includes a display and a processor. The processor is arranged to determine scan data for slices and/or slices of the part to be built in the additive manufacturing process and cause the display to display scan data and/or slices that has been determined whilst determining scan data for other ones of the slices and/or other ones of the slices from the geometric data.

Abstract: An optical element for generating diffraction orders for an encoder apparatus, in which the optical element includes an array of diffraction features arranged such that the spacing between the centers of adjacent diffraction features varies irregularly from one pair of adjacent features to the next.

Abstract: A method of finding a feature of an object using an analog probe mounted on a machine tool. The method includes the analog probe and/or object following a course of motion which causes the analog probe's surface sensing region to traverse across the feature to be found a plurality of times while approaching the feature over successive traverses so as to ultimately arrive in a position sensing relationship with the feature so as to collect scanned measurement data about the feature along at least part of a traverse.

Abstract: A method is described for analysing probe data collected by a scanning probe carried by a machine tool. The probe data is collected as the machine tool moves or scans the scanning probe along a scan path relative to a workpiece. The method includes a step of identifying a property of the scan path used by the machine tool from a characteristic of the collected probe data. In this manner, the scan path can be identified from the probe data alone without having to receive any position data from the machine tool.

Abstract: A measurement scale device includes at least one scale marking, wherein the or each scale marking includes at least one periodic nanostructure that represents scale device information.

Abstract: An additive manufacturing apparatus comprises a processing chamber defining a window for receiving a laser beam and an optical module. The optical module is removably-mountable to the processing chamber for delivering the laser beam through the window. The optical module contains optical components for focusing and steering the laser beam and a controlled atmosphere can be maintained within the module.