Abstract: 3D metrology techniques are disclosed for determining a changing topography of a substrate processed in an additive manufacturing system. Techniques include fringe scanning, simultaneous fringe projections, interferometry, and x-ray imaging. The techniques can be applied to 3D printing systems to enable rapid topographical measurements of a 3D printer powder bed, or other rapidly moving, nearly continuous surface to be tested. The techniques act in parallel to the system being measured to provide information about system operation and the topography of the product being processed. A tool is provided for achieving higher precision, increasing throughput, and reducing the cost of operation through early detection and diagnosis of operating problems and printing defects. These techniques work well with any powder bed 3D printing system, providing real-time metrology of the powder bed, the most recently printed layer, or both without reducing throughput.

Abstract: The problem of limited throughput in three-dimensional (3D) printing processes is addressed by systems and methods that employ mirrors to receive energy reflected by the melt pool and to redirect such light back to the melt pool, where it may further heat the melt pool. Multiple such passes of reflection from the melt pool and redirection back to the melt pool may substantially increase the efficiency at which the melt pool absorbs the energy, thereby substantially increasing the throughput of the 3D printing process.

Abstract: The problem of measuring the temperature of a 3D printing process is addressed by systems and methods that apply imaging spectrometry to measure blackbody radiation emitted before, during, or after a 3D printing process. The systems and methods utilize a pair of lenses, a field stop, and a wavelength separator to direct a plurality of wavelengths corresponding to the blackbody radiation to pixels of an optical detector. The plurality of wavelengths are analyzed by a controller to determine the temperature of the 3D printed component.

Abstract: 3D metrology techniques are disclosed for determining a changing topography of a substrate processed in an additive manufacturing system. Techniques include fringe scanning, simultaneous fringe projections, interferometry, and x-ray imaging. The techniques can be applied to 3D printing systems to enable rapid topographical measurements of a 3D printer powder bed, or other rapidly moving, nearly continuous surface to be tested. The techniques act in parallel to the system being measured to provide information about system operation and the topography of the product being processed. A tool is provided for achieving higher precision, increasing throughput, and reducing the cost of operation through early detection and diagnosis of operating problems and printing defects. These techniques work well with any powder bed 3D printing system, providing real-time metrology of the powder bed, the most recently printed layer, or both without reducing throughput.

Abstract: Surface changes are estimated using multiple speckle interferograms acquired using beams incident at different angles. Beam irradiation conditions can be changed to increase signal to noise ratio with averaging, such as weighted averaging. Irradiation conditions can be varied with a tilt plate, a wedge, or by changing beam wavelengths.

Abstract: A system for measuring a target grating includes an illumination source, a reference transmission grating, a pupil filter, and a detector. The illumination source is disposed to generate an incident light beam that illuminates the reference transmission grating. The reference transmission grating splits the incident light beam into a plurality of diffraction orders. The plurality of diffraction orders interrogates a target grating. The reference transmission grating and the target grating are parallel. The pupil filter allows transmission of a subset of diffraction orders of light that has been diffracted and/or reflected from the target grating after being split again by passing through the reference transmission grating. The detector takes a measurement of the subset of diffraction orders of light after transmission through the pupil filter.

Abstract: A processing machine (10) for building an object (11) from powder (12) includes a build platform (26A); a powder supply assembly (18) that deposits the powder (12) onto the build platform (26A) to form a powder layer (13); and an energy system (22) that directs an energy beam (22D) at a portion of the powder (12) on the build platform (26A) to form a portion of the object (11). The powder supply assembly (18) can include (i) a powder container (640A) that retains the powder (12); (ii) a supply outlet (639) positioned over the build platform (26A); and (ii) a flow control assembly (642) that selectively controls the flow of the powder (12) from the supply outlet (639).

Abstract: The problem of measuring height properties (for instance, for aspheric optical components) is addressed by systems and methods that employ heterodyne optical interferometry to detect a plurality of interference patterns corresponding to a plurality of orientations of the surface and that determine a height property (such as a mid-spatial frequency spectrum or topography) of the surface from the plurality of interference patterns.

Abstract: A processing machine (10) for building an object (11) from powder (12) includes a build platform (26A); a powder supply assembly (18) that deposits the powder (12) onto the build platform (26A) to form a powder layer (13); and an energy system (22) that directs an energy beam (22D) at a portion of the powder (12) on the build platform (26A) to form a portion of the object (11). The powder supply assembly (18) can include (i) a powder container (640A) that retains the powder (12); (ii) a supply outlet (639) positioned over the build platform (26A); and (ii) a flow control assembly (642) that selectively controls the flow of the powder (12) from the supply outlet (639).

Abstract: Detectors are situated along a tilted optical axis to receive optical radiation from a work surface. Variations in the received optical power are used to estimate a work surface positional along a work surface axis. The received optical power can be emitted from the work surface and an estimated temperature of the work surface used to adjust the received optical power. One or two single element detectors or a linear detector can be used. A position of a focused spot produced from the received optical power at the linear detector can be used to assess work surface axial position.

Abstract: Shearography systems provide independent setting of fringe frequency and shear magnitude by situating an interferometer with a tiltable reflector proximate a pupil plane of an imaging optical system. Fringe frequency can be selected based on a modified Savart plate. In other examples, a Wollaston prism or a polarization grating is translated with respect to an image sensor to vary shear magnitude while maintaining a substantially fixed fringe frequency.

Abstract: The problem of limited throughput in three-dimensional (3D) printing processes is addressed by systems and methods that employ mirrors to receive energy reflected by the melt pool and to redirect such light back to the melt pool, where it may further heat the melt pool. Multiple such passes of reflection from the melt pool and redirection back to the melt pool may substantially increase the efficiency at which the melt pool absorbs the energy, thereby substantially increasing the throughput of the 3D printing process.

Abstract: The problem of measuring the temperature of a 3D printing process is addressed by systems and methods that apply imaging spectrometry to measure blackbody radiation emitted before, during, or after a 3D printing process. The systems and methods utilize a pair of lenses, a field stop, and a wavelength separator to direct a plurality of wavelengths corresponding to the blackbody radiation to pixels of an optical detector. The plurality of wavelengths are analyzed by a controller to determine the temperature of the 3D printed component.

Abstract: 3D metrology techniques are disclosed for determining a changing topography of a substrate processed in an additive manufacturing system. Techniques include fringe scanning, simultaneous fringe projections, interferometry, and x-ray imaging. The techniques can be applied to 3D printing systems to enable rapid topographical measurements of a 3D printer powder bed, or other rapidly moving, nearly continuous surface to be tested. The techniques act in parallel to the system being measured to provide information about system operation and the topography of the product being processed. A tool is provided for achieving higher precision, increasing throughput, and reducing the cost of operation through early detection and diagnosis of operating problems and printing defects. These techniques work well with any powder bed 3D printing system, providing real-time metrology of the powder bed, the most recently printed layer, or both without reducing throughput.

Abstract: To improve the operation of 3D printing systems, techniques are disclosed for a rotary 3D printer comprising: a main rotating support table rotating about a first axis and one or more secondary support tables rotating around a non-coaxial secondary axis; a powder supply assembly for distributing powder onto the tables; and an energy system for directing an energy beam at the powder to form a part. The main support table and secondary support tables can rotate in the same or opposite directions. Disclosed techniques include: grooved support table surfaces for improving stability of applied powder; reciprocating bellows for controlling a differential load on actuators that move the support tables; high temperature bearings or bushings for supporting rotary motion at high temperatures; and a mechanism for counterbalancing a weight of the part being built.

Abstract: Surface changes are estimated using multiple speckle interferograms acquired using beams incident at different angles. Beam irradiation conditions can be changed to increase signal to noise ratio with averaging, such as weighted averaging. Irradiation conditions can be varied with a tilt plate, a wedge, or by changing beam wavelengths.

Abstract: Object interference in biological samples generated by lateral shearing interference microscopes is addressed by a shearing microscope slide comprising a periodic structure having alternating reference and sample regions. In some embodiments, the reference regions are configured to provide references that remove sample overlap in a sheared microscopic measurement. A system for generating sheared microscopic measurements is also provided that comprises an inlet configured to receive a sample material, an outlet configured to release a portion of the sample material, and a periodic structure having a plurality of interleaved reference and sample channels. In some cases, the sample channels are configured to accommodate a flow of sample material from the inlet to the outlet and the reference channels are configured to provide references that remove sample overlap in a sheared microscopic measurement.

Abstract: Object interference in biological samples generated by lateral shearing interference microscopes is addressed by a shearing microscope slide comprising a periodic structure having alternating reference and sample regions. In some embodiments, the reference regions are configured to provide references that remove sample overlap in a sheared microscopic measurement. A system for generating sheared microscopic measurements is also provided that comprises an inlet configured to receive a sample material, an outlet configured to release a portion of the sample material, and a periodic structure having a plurality of interleaved reference and sample channels. In some cases, the sample channels are configured to accommodate a flow of sample material from the inlet to the outlet and the reference channels are configured to provide references that remove sample overlap in a sheared microscopic measurement.

Abstract: System and method for monitoring of performance of a mirror array of a digital scanner with a use of light, illuminating the mirror array at grazing (off-axis) incidence, and an optical imaging system that includes a lateral shearing interferometer (operated in either static or a phase-shifting condition) during and without interrupting the process of exposure of the workpiece with the digital scanner, to either simply identify problematic pixels for further troubleshooting or measure the exact magnitude of the deformation of a mirror element of the mirror array.

Abstract: Prediction of a distribution of light in an illumination pupil of an illumination system includes identifying component(s) of the illumination system the adjustment of which affects this distribution and simulating the distribution based on a point spread function defined in part by the identified components. The point spread function has functional relationship with configurable setting of the illumination settings.