Abstract: A curing system for an additive fabrication system includes a light source, a liquid crystal cell, and a first polarizer. The light source is configured to emit light at a wavelength suitable for curing a material. The liquid crystal cell is configured to receive the light from the light source. The first polarizer comprises a polyvinyl alcohol (PVA) matrix and organic dyes impregnated into the PVA matrix.

Abstract: Techniques for improved efficiency of sintering in additive fabrication are described. According to some aspects, mechanisms for depositing and leveling source material are combined with a mechanism for heating the material. In some embodiments, one or more heating elements may be arranged to lead and/or follow a material deposition mechanism such that heat may be applied to the build region in concert with deposition of material. As a result of this technique, the heating and depositing steps may be performed closer together in time and/or heat may be applied more directly to the material than in conventional systems. As a result, greater control over material temperature may be achieved, thereby avoiding excess temperature exposure and subsequent undesirable changes to the material.

Abstract: Methods and compositions for additive manufacturing of silicone parts are provided. The methods can use SLA printing techniques to print silicone parts that exhibit excellent hardness, tear strength and elongation at break. The parts can be produced by using low dosages of radiation. In various embodiments, the silicone compositions include a mercapto-derivatized polysiloxane having two or more functional groups, an alkenyl-derivatized polysiloxane, and a photo-initiator.

Abstract: Techniques are described for fabricating parts in an additive fabrication device from a light-scattering build material, such as ceramic build materials. An additive fabrication device may comprise a container for holding a photo-polymerizable build material containing a light-scattering species such as ceramic particles. The bottom of the tank may comprise one or more light-absorbing additives that absorb a portion of the actinic radiation used to cure the build material. The one or more light-absorbing additives may include an absorptive dye, including inorganic pigments like carbon black, organic dyes, or other species.

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, an additive fabrication device and a build platform suitable for use within an additive fabrication device are provided. The build platform may include a build surface on which material may be formed by the additive fabrication device when the build platform is installed within the additive fabrication device. According to some embodiments, the build platform may include a flexible build layer and at least one removal mechanism configured to be actuated to apply a force to the flexible build layer. Such actuation may cause the flexible build layer to deform, thereby enabling separation of material adhered to the build surface from the build platform. According to some embodiments, the build platform may comprise a restorative mechanism that acts to return the flexible build layer to a flat state so that subsequent additive fabrication may form material on a flat build surface.

Abstract: A method includes curing a photopolymer resin disposed between a first build surface and a flexible film layer to form a print layer of a printed part. Here, the print layer of the printed part defines a second build surface attached to the flexible film layer. The method also includes translating a peeling mechanism between the second build surface and the flexible film layer to detach the flexible film layer from the second build surface.

Abstract: A method and system for tensioning film tank in a liquid photopolymer container designed for use in a stereolithography (SLA) additive fabrication device is disclosed. The liquid photopolymer container comprises a tank frame, a film clamp that attaches to the tank frame and secures a film between the clamp and the tank frame, and a film positioned between the clamp and the bottom surface of the tank frame. The film clamp and the tank frame include raised-features and recesses that mate together to increase the grip on the film.

Abstract: An improved additive fabrication device and a build platform are provided. The additive fabrication device is configured to form layers of material on a build surface. The additive fabrication device comprising: a build platform comprising: a rigid structure; an actuation structure attached to the rigid structure, wherein the actuation structure comprises one or more sheet handles and a flexible sheet, and wherein a first surface of the flexible sheet forms a build surface on which the additive fabrication device is configured to form layers of materials; and the one or more sheet handles are configured to be actuated to apply a force to the flexible sheet while at least a part of the actuation structure remains attached to the rigid structure, to deform at least a part of the flexible sheet away from the rigid structure.

Abstract: A multi-component print surface and associated additive manufacturing methods are generally described.

Abstract: Techniques to allow an additive fabrication device to dynamically adjust the size of a post metering volume for adjusting pressure of source material in the volume. These techniques may allow for greater control of material extrusion through an orifice and thereby mitigate or avoid issues of lag time between starting and/or stopping extrusion and/or in which there is unwanted emission of source material through the orifice. In some cases, techniques for adjusting the size of the post metering volume may include operating an actuator arranged in a channel that is coupled to the post metering volume. In some cases, techniques for adjusting the size of the post metering volume may include having a stator that is at least partially arranged within a chamber that defines the post metering volume and is free to move within the chamber.

Abstract: Techniques are described for calibrating an optical system in an additive fabrication device using an image of the build surface within the device. These techniques allow calibration to be performed by imaging one or more calibration features generated on (or at) the build surface, which may include illuminated regions of the build surface, regions of the build surface on which solid material has been formed, and/or regions of the build surface to which energy has otherwise been directed thereby making those regions distinguishable from their surroundings. The calibration features may be produced (at least in part) by the optical system to be calibrated. The location of the calibration features within the image may be compared with the intended location of these calibration features, and corrections to the optical system determined based on any differences between the actual and intended locations.

Abstract: According to some aspects, a method is provided of casting an object from a mold, the method comprising obtaining a mold comprising a hollow shell of rigid material, the material comprising a thermoset polymer having a plurality of pores formed therein, providing a metal and/or ceramic slurry into an interior of the mold, exposing at least part of the mold to a low pressure environment so that a net flow of gas is produced from the interior of the mold into the low pressure environment. According to some aspects, a method of forming a porous mold is provided. According to some aspects, a photocurable liquid composition is provided, comprising a liquid photopolymer resin, particles of a solid material, in an amount between 30% and 60% by volume of the composition, and a water-soluble liquid.

Abstract: Washing apparatus and methods used to process additively fabricated (e.g., 3D printed) parts are described herein. The apparatus and methods may be used to wash uncured liquid resin from the parts.

Abstract: A multi-component composition for additive manufacturing, and related methods, are generally described.

Abstract: Techniques for improved efficiency of sintering in additive fabrication are described. According to some aspects, mechanisms for depositing and leveling source material are combined with a mechanism for heating the material. In some embodiments, one or more heating elements may be arranged to lead and/or follow a material deposition mechanism such that heat may be applied to the build region in concert with deposition of material. As a result of this technique, the heating and depositing steps may be performed closer together in time and/or heat may be applied more directly to the material than in conventional systems. As a result, greater control over material temperature may be achieved, thereby avoiding excess temperature exposure and subsequent undesirable changes to the material.

Abstract: According to some aspects, an additive fabrication device and a build platform suitable for use within an additive fabrication device are provided. The build platform may include a build surface on which material may be formed by the additive fabrication device when the build platform is installed within the additive fabrication device. According to some embodiments, the build platform may include a flexible build layer and at least one removal mechanism configured to be actuated to apply a force to the flexible build layer. Such actuation may cause the flexible build layer to deform, thereby enabling separation of material adhered to the build surface from the build platform. According to some embodiments, the build platform may comprise a restorative mechanism that acts to return the flexible build layer to a flat state so that subsequent additive fabrication may form material on a flat build surface.

Abstract: Methods and systems of producing a 3D object on a selective laser sintering device are described. The method involves retaining a first layer of powder of uniform thickness on a build platform, scanning a laser beam along a predetermined path to consolidate portions of the first layer of powder to form a cross-section of the 3D object, and depositing a second layer of powder of uniform thickness on top of the first layer prior to completing the scanning process. The powder deposition device is moved from one end of the build platform to the other, depositing the second layer on both the loose powder and the previously consolidated powder.

Abstract: According to some aspects, degradation of material in a sintering additive fabrication process may be mitigated or avoided by fabricating parts within a chamber that includes one or more thermal breaks. The thermal break may be implemented using a variety of structures, but generally allows material in the chamber close to the surface to be maintained at different temperatures than the material further from the surface. For instance, as a result of the thermal break, parts located within the material of the chamber that were formed earlier during fabrication may be kept cooler to avoid damage to the parts yet the upper surface (sometimes called the “build surface”) of unconsolidated material may be heated enough so as to require minimal additional energy exposure to trigger consolidation.

Abstract: Techniques are described to gather information from an end user relating to fabrication process failures in a standardized manner. This information may be provided to an additive fabrication device manufacturer and analyzed by the manufacturer. Analysis may include identifying patterns in the data to identity problems relating to an additive fabrication device, software used to operate the device and/or user operations. Identification of such patterns may aid in selecting and/or generating support solutions to be provided the end user, or to improve the additive fabrication device and/or software.