Abstract:
This invention concerns a selective solidification apparatus including a build chamber, a build platform lowerable in the build chamber, a wiper for spreading powder material across the build platform to form successive powder layers of a powder bed, an energy beam unit for generating an energy beam for consolidating the powder material, a scanner for directing and focussing the energy beam onto each powder layer and a processor for controlling the scanner. The processor is arranged to control the scanner to scan the energy beam across the powder bed to consolidate powder material either side of the wiper when the wiper is moving across the powder bed and to scan the energy beam across at least one of the powder layers during two or more strokes of the wiper across the powder bed.
Abstract:
A magnetic encoder apparatus is presented that includes a plurality of magnetic sensor elements (e.g. Hall sensors) for reading an associated magnetic scale that produces a periodically repeating magnetic pattern. The plurality of magnetic sensor elements produce a plurality of sensor signals and an analyzer is provided for analyzing the plurality of sensor signals to provide a measure of the position of the magnetic sensor elements relative to the associated magnetic scale. The analyzer is arranged to use the plurality of sensor signals to assess the period of the periodically repeating magnetic pattern sensed by the plurality of magnetic sensor elements. In this manner, the requirement to carefully match the period of the sensor elements with the periodically repeating magnetic pattern of the associated magnetic scale is avoided.
Abstract:
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.
Abstract:
A method and apparatus for generating geometric data are to be used in the building of an object using a layer-by-layer additive manufacturing process. The method includes providing object data defining the object, identifying from the object data one or more regions of a surface of the object to be supported during the additive manufacturing process and, for the or each region, identifying one or more supporting structures that will provide support for the region and generating an arrangement of supports within the region. A support location of each support of the arrangement relative to the other supports of the arrangement is derived from a location of the supporting structures.
Abstract:
This invention concerns spectroscopy apparatus comprising a light source arranged to generate a light profile on a sample, a photodetector having at least one photodetector element for detecting characteristic light generated from interaction of the sample with light from the light source, a support for supporting the sample, the support movable relative to the light profile, and a processing unit. The processing unit is arranged to associate a spectral value recorded by the photodetector element at a particular time with a point on the sample predicted to have generated the characteristic light recorded by the photodetector element at the particular time based on relative motion anticipated to have occurred between the support and the light profile.
Abstract:
A method of assembling a device including, taking a casing including a body having an opening and a lid for the opening, locating at least one electronic component within the body; locating a first end of a cable for electrically connecting the electronic component within the body to an external device, and deforming at least one of the body and the lid so as to secure the lid to the body and such that the cable is secured to the casing by the lid.
Abstract:
A method is described for calculating an optimum stand-off distance for surface position measurements to be acquired by a coordinate positioning apparatus including a measurement probe. The coordinate positioning apparatus may include a machine tool and the measurement probe may include a touch trigger probe having a deflectable stylus. The method includes the step of calculating an optimum stand-off distance using at least one measured acceleration characteristic of the coordinate positioning apparatus. In this manner, measurement cycle times may be optimised.
Abstract:
A method is described for using coordinate positioning apparatus, such as a machine tool, to measure an object. The method includes the step of operating the coordinate positioning apparatus in a touch trigger mode to measure the position of one or more touch trigger measurement points on the surface of the object. The coordinate positioning apparatus is also operated in a scanning mode to measure the position of a plurality of scanned measurement points along a scan path on the surface of the object, the scanning mode measurements being acquired using a scanning probe having an object-contacting stylus. At least one correction (Δi;V,R;Δr) is then calculated that describes a difference between the touch trigger mode measurements and the scanning mode measurements. In this manner, touch trigger measurements are used to correct scanning measurements.
Abstract:
An additive manufacturing machine for building objects by layerwise melting of powder material includes a build chamber containing a build platform, a powder dispenser depositing the powder material in layers across the platform, a high energy beam selectively melting powder material in each layer and a control device controlling a property of the powder material given by build particles in the powder material below a specified upper particle size limit. A method includes controlling a property of the powder material given by build particles below a specified upper particle size limit. A method carries out successive builds, wherein in-between the builds, particles are added to or removed from the powder material to effect a property of the powder material given by build particles below a specified upper particle size limit. Further, adding or removing particles ensure that a sufficient proportion of micro build particles are present in the powder.
Abstract:
A metrology apparatus including a body and a first member rotatable relative to the body about a first axis of rotation, said first axis being defined by first bearing and a first motor for actuating rotation of the first member relative to the body about the first axis of rotation. A surface sensing device is attachable to the first member such that the surface sensing device can move with the first member, relative to the body. The first motor may include a first magnet and at least one metal coil spaced apart along the first axis and mounted such that the first magnet and the at least one metal coil are moveable relative to one another.