Abstract: According to some aspects, techniques that address one or more drawbacks of laser-based optical systems in additive fabrication devices are described. In some aspects, an additive fabrication device may include one or more variable focus lenses that may be operated (e.g., actuated) during fabrication to adjust the focus, and thereby the spot size, of a laser beam. In some aspects, an additive fabrication device may comprise a laser array, such as a plurality of vertical-cavity surface-emitting lasers (VCSELs), that may be operated to direct light into a build region, rather than using a single laser beam, such as a single diode laser. In some aspects, an additive fabrication device may comprise a container that includes a flexible display film, such as a flexible LCD screen, which may be operated to direct light into the container to thereby cure a liquid photopolymer therein.

Abstract: According to some aspects, techniques are provided for identifying contamination in additive fabrication devices by measuring light interacting with the contamination using one or more light sensors. Contamination located between a light source and a target of a light source can affect the uniformity and intensity of the light source when incident upon the target. For instance, in an inverse stereolithography device, contamination located between a light source and a liquid photopolymer resin that is to be cured can affect the quality of the fabricated object when the light is scattered or blocked by the contamination. Identifying the presence of contamination between the light source and the liquid photopolymer resin and alerting the user prior to initiating a fabrication process may increase the quality of the resulting fabricated object and improve the user experience by saving time and photocurable liquid.

Abstract: Techniques for illuminating a photocurable material within a build area of an additive fabrication device are described. According to some aspects, a light source is provided that can be moved alongside a build area, allowing light to be directed to any desired position within the build area by moving the light source. This configuration may also allow the distance from the light source to the build area to be substantially the same for each position across the build area by moving the light source whilst maintaining a fixed distance from the light source to the build volume. The described approach may allow for fabrication of larger parts in an additive fabrication device by expanding or eliminating the practical upper limit on the area of the build volume that can be imposed by use of a laser light source in such a device.

Abstract: According to some aspects, techniques are provided for identifying contamination in additive fabrication devices by measuring light interacting with the contamination using one or more light sensors. Contamination located between a light source and a target of a light source can affect the uniformity and intensity of the light source when incident upon the target. For instance, in an inverse stereolithography device, contamination located between a light source and a liquid photopolymer resin that is to be cured can affect the quality of the fabricated object when the light is scattered or blocked by the contamination. Identifying the presence of contamination between the light source and the liquid photopolymer resin and alerting the user prior to initiating a fabrication process may increase the quality of the resulting fabricated object and improve the user experience by saving time and photocurable liquid.

Abstract: According to some aspects, calibration techniques are provided that allow an optics module of an additive fabrication device to be installed and operated in a stereolithography device by a user. In particular, the calibration techniques enable the optics module to be calibrated in a way that only depends on the characteristics of the optics module, and not upon any other components of the stereolithography device. As a result, the techniques enable a user of a stereolithography device to remove one optics module and replace it with another, without it being necessary to repair or replace the whole device. In some cases, the calibration techniques may include directing light onto one or more fiducial targets within the stereolithography device and measuring light scattered from said targets.

Abstract: Techniques for illuminating a photocurable material within a build area of an additive fabrication device are described. According to some aspects, a light source is provided that can be moved alongside a build area, allowing light to be directed to any desired position within the build area by moving the light source. This configuration may also allow the distance from the light source to the build area to be substantially the same for each position across the build area by moving the light source whilst maintaining a fixed distance from the light source to the build volume. The described approach may allow for fabrication of larger parts in an additive fabrication device by expanding or eliminating the practical upper limit on the area of the build volume that can be imposed by use of a laser light source in such a device.

Abstract: Techniques for directing light from a movable stage in an additive fabrication device are provided. According to some aspects, the movable stage may include a parabolic mirror onto which light may be directed at various different incident angles to produce light along different positions along an axis. In some cases, this axis may be perpendicular to a direction of motion of the movable stage.

Abstract: According to some aspects, techniques are provided to more accurately produce fine features in additive fabrication. According to some embodiments, the techniques comprise a process that amplifies exposure to edges and thin positive features whilst not substantially affecting negative features. In particular, an area to be cured may be adapted using signal processing techniques to produce an energy density map. The area may subsequently be cured according to the generated energy density map by, for example, adjusting the scan speed, light power and/or number of passes of the light beam according to the map. As a result, the net exposure to edges and thin positive features may be amplified.

Abstract: According to some aspects, techniques that address one or more drawbacks of laser-based optical systems in additive fabrication devices are described. In some aspects, an additive fabrication device may include one or more variable focus lenses that may be operated (e.g., actuated) during fabrication to adjust the focus, and thereby the spot size, of a laser beam. In some aspects, an additive fabrication device may comprise a laser array, such as a plurality of vertical-cavity surface-emitting lasers (VCSELs), that may be operated to direct light into a build region, rather than using a single laser beam, such as a single diode laser. In some aspects, an additive fabrication device may comprise a container that includes a flexible display film, such as a flexible LCD screen, which may be operated to direct light into the container to thereby cure a liquid photopolymer therein.

Abstract: Techniques for illuminating a photocurable material within a build area of an additive fabrication device are described. According to some aspects, a light source is provided that can be moved alongside a build area, allowing light to be directed to any desired position within the build area by moving the light source. This configuration may also allow the distance from the light source to the build area to be substantially the same for each position across the build area by moving the light source whilst maintaining a fixed distance from the light source to the build volume. The described approach may allow for fabrication of larger parts in an additive fabrication device by expanding or eliminating the practical upper limit on the area of the build volume that can be imposed by use of a laser light source in such a device.

Abstract: Techniques are described for tagging source materials for additive fabrication by incorporating a fluorescent and/or phosphorescent taggant into the source material. A light source within an additive fabrication device may direct light onto the source material and a light sensor may detect whether light having appropriate characteristics was produced from the source material through fluorescence and/or phosphorescence. If such light is detected, the additive fabrication device may determine that the source material is from an approved source and thereby has known properties that may be relied upon for fabrication. Otherwise, the additive fabrication device may determine that the source material is from an unapproved source and may take action such as inhibiting fabrication and/or providing a warning to a user.

Abstract: According to some aspects, techniques are provided to more accurately produce fine features in additive fabrication. According to some embodiments, the techniques comprise a process that amplifies exposure to edges and thin positive features whilst not substantially affecting negative features. In particular, an area to be cured may be adapted using signal processing techniques to produce an energy density map. The area may subsequently be cured according to the generated energy density map by, for example, adjusting the scan speed, light power and/or number of passes of the light beam according to the map. As a result, the net exposure to edges and thin positive features may be amplified.

Abstract: According to some aspects, calibration techniques are provided that allow an optics module of an additive fabrication device to be installed and operated in a stereolithography device by a user. In particular, the calibration techniques enable the optics module to be calibrated in a way that only depends on the characteristics of the optics module, and not upon any other components of the stereolithography device. As a result, the techniques enable a user of a stereolithography device to remove one optics module and replace it with another, without it being necessary to repair or replace the whole device. In some cases, the calibration techniques may include directing light onto one or more fiducial targets within the stereolithography device and measuring light scattered from said targets.

Abstract: According to some aspects, techniques are provided for identifying contamination in additive fabrication devices by measuring light interacting with the contamination using one or more light sensors. Contamination located between a light source and a target of a light source can affect the uniformity and intensity of the light source when incident upon the target. For instance, in an inverse stereolithography device, contamination located between a light source and a liquid photopolymer resin that is to be cured can affect the quality of the fabricated object when the light is scattered or blocked by the contamination. Identifying the presence of contamination between the light source and the liquid photopolymer resin and alerting the user prior to initiating a fabrication process may increase the quality of the resulting fabricated object and improve the user experience by saving time and photocurable liquid.

Abstract: A communication system that involves superimposing data over DC power. The data takes the form of high bitrate digital signals, where the bitrate is much higher than 0 Hz (DC); this separation allows the AC signal to be easily separated from the DC power. The physical system consists of a two conductor cable, and integration is modular, in that multiple slaves can be connected and disconnected to a master through a routing bus also comprising two conductors. The master can communicate bi-directionally with the slave(s), and the data is encoded using DC-balanced encoding in an FPGA. The data is sent to and from a differential signaling transmitter/receiver pairs at each end of the cable. The system is may be used with position sensors, and provides the benefit of reducing cable costs and sensor size due to the decrease in number of conductors and elimination of power components in the sensor.

Abstract: Techniques for directing light from a movable stage in an additive fabrication device are provided. According to some aspects, the movable stage may include a parabolic mirror onto which light may be directed at various different incident angles to produce light along different positions along an axis. In some cases, this axis may be perpendicular to a direction of motion of the movable stage.

Abstract: Techniques for illuminating a photocurable material within a build area of an additive fabrication device are described. According to some aspects, a light source is provided that can be moved alongside a build area, allowing light to be directed to any desired position within the build area by moving the light source. This configuration may also allow the distance from the light source to the build area to be substantially the same for each position across the build area by moving the light source whilst maintaining a fixed distance from the light source to the build volume. The described approach may allow for fabrication of larger parts in an additive fabrication device by expanding or eliminating the practical upper limit on the area of the build volume that can be imposed by use of a laser light source in such a device.

Abstract: An optical position encoder includes a scale having multiple tracks separated in a direction perpendicular to travel, the tracks including an incremental track and an absolute track, the scale interacting with an incident first light beam to generate a second light beam having components carrying respective optical patterns produced by the incremental track and absolute track respectively. The encoder further includes a set of optical detectors including at least first and second detector arrays of differing properties to detect the respective optical patterns produced by the incremental track and absolute track respectively, each of the first and second detector arrays spanning multiple tracks of the scale and configured to respond to a respective detector-specific component of the second light beam more strongly than to another component of the second beam specific to another of the detector arrays.

Abstract: A communication system that involves superimposing data over DC power. The data takes the form of high bitrate digital signals, where the bitrate is much higher than 0 Hz (DC); this separation allows the AC signal to be easily separated from the DC power. The physical system consists of a two conductor cable, and integration is modular, in that multiple slaves can be connected and disconnected to a master through a routing bus also comprising two conductors. The master can communicate bi-directionally with the slave(s), and the data is encoded using DC-balanced encoding in an FPGA. The data is sent to and from a differential signaling transmitter/receiver pairs at each end of the cable. The system is may be used with position sensors, and provides the benefit of reducing cable costs and sensor size due to the decrease in number of conductors and elimination of power components in the sensor.

Abstract: An optical position encoder includes a scale having multiple tracks separated in a direction perpendicular to travel, the tracks including an incremental track and an absolute track, the scale interacting with an incident first light beam to generate a second light beam having components carrying respective optical patterns produced by the incremental track and absolute track respectively. The encoder further includes a set of optical detectors including at least first and second detector arrays of differing properties to detect the respective optical patterns produced by the incremental track and absolute track respectively, each of the first and second detector arrays spanning multiple tracks of the scale and configured to respond to a respective detector-specific component of the second light beam more strongly than to another component of the second beam specific to another of the detector arrays.