Abstract: A method and apparatus for determining an alignment of an optical scanner for directing an electromagnetic beam to locations within a scan field. The method may include locating a reference element within the scan field of the optical scanner and controlling the optical scanner to cause the electromagnetic beam to be directed to a plurality of different points in the scan field, including at least one point on the reference element. Reflected electromagnetic radiation is detected. The method may include determining when the electromagnetic beam is directed to a reference position in the scan field given by the reference element from a comparison of an intensity of the detected electromagnetic radiation for the different points and determining a corresponding demand signal that causes the optical scanner to direct the electromagnetic beam to the reference position.

Abstract: A method of aligning an on-axis melt pool sensor in an additive manufacturing apparatus. The method includes scanning a first laser beam along a first scan path across a working surface using a first optical train to generate a melt pool along the first scan path and scanning a field of view of an on-axis sensor along a second scan path across the working surface using a second optical train for steering a second laser beam. The first and second scan paths intersect. An adjustment to be made to an alignment of the field of view of the on-axis sensor with an optical axis of the second optical train is determined from a variation in the signal generated by the on-axis sensor as the field of view is scanned along the second scan path.

Abstract: A method of monitoring an additive manufacturing process, in which an object is built in a layer-by-layer manner by directing a laser beam using at least one movable guiding element of a scanner to solidify selected regions of a material bed. The method includes recording position values generated from a transducer measuring positions of the at least one movable guiding element, recording sensor values generated from a sensor for detecting radiation emitted from the material bed and transmitted to the sensor by the movable guiding element of the scanner, and associating each sensor value with a corresponding one of the position values.

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 laser solidification apparatus for building objects by layerwise solidification of material. The laser solidification apparatus includes a build platform for supporting the object and a material bed, an optical module including a movable guiding element for directing the laser beam to solidify material of the material bed, and a detector module including a sensor for detecting radiation emitted from the material bed and transmitted to the sensor by the movable guiding element of the optical module. The detector module is removably mounted to the optical module.

Abstract: A method of monitoring an additive manufacturing process, in which an object is built in a layer-by-layer manner by directing a laser beam using at least one movable guiding element of a scanner to solidify selected regions of a material bed. The method includes recording position values generated from a transducer measuring positions of the at least one movable guiding element, recording sensor values generated from a sensor for detecting radiation emitted from the material bed and transmitted to the sensor by the movable guiding element of the scanner, and associating each sensor value with a corresponding one of the position values.

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: 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: 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: A method of reading data represented by a marking including at least one periodic nanostructure, the marking representing data using a polarisation property of the periodic nanostructure. The method includes detecting polarised electromagnetic radiation reflected from or transmitted by the nanostructure, and determining the data represented by the marking from the detected polarised electromagnetic radiation, wherein the method further includes applying polarised electromagnetic radiation to the nanostructure, and/or the detecting is performed using a polarisation-sensitive detector apparatus.