Abstract: A composition for forming a microlattice structure includes a photopolymerizable compound and a flame retardant material. A microlattice structure includes a plurality of struts interconnected at a plurality of nodes, the struts including: a copolymer including a reaction product of a photopolymerizable compound and a flame retardant material. A microlattice structure includes a plurality of struts interconnected at a plurality of nodes, the struts including: a polymer including a reaction product of a photopolymerizable compound; and a flame retardant material.

Abstract: A method of manufacturing an ordered cellular structure including a series of interconnected unit cells. Each unit cell includes at least one straight wall segment. The method includes irradiating a volume of photo-monomer in a reservoir with at least one light beam from at least one light source to form the ordered cellular structure. Irradiating the volume of photo-monomer includes directing the at least one light beam though a series of interconnected apertures defined in a photo-mask covering the reservoir.

Abstract: Branched hierarchical micro-truss structures may be incorporated into energy-absorbing structures to exhibit a tailored multi-stage buckling response to a range of different compressive loads. Branched hierarchical micro-truss structures may also be configured to function as vascular systems to deliver fluid for thermal load management or altering the aerodynamic properties of a vehicle or structure into which the branched hierarchical micro-truss structure is incorporated. The branched hierarchical micro-truss structure includes a first layer having a series of interconnected struts and a second layer having a series of struts branching outward from an end of each of the struts in the first layer.

Abstract: A sacrificial substrate for use in stereolithography, having a first surface configured to be attached to a build platform, and a second surface of the sacrificial substrate configured to be attached to a photopolymer part. The sacrificial substrate physically separates the build platform and the photopolymer part, and serves as the deposition surface for the photopolymer part in place of the build platform. The sacrificial substrate may be separated from the build platform and then separated from the photopolymer part via pyrolysis, oxidation, or etching to thereby yield the free photopolymer part without subjecting the part to excess physical force or damage.

Abstract: Methods of manufacturing a structure having at least one plated region and at least one unplated region. The method includes plating a metal on a polymer structure having a first region accepting the metal and a second region unreceptive to the metal plating. The first region may include fully-cured polymer optical waveguides and the second region may include partially-cured polymer optical waveguides. The first region may include a first polymer composition and the second region may include a second polymer composition different than the first polymer composition.

Abstract: A method and/or system for forming a micro-truss structure in an essentially arbitrary shape. A mold that has a transparent portion, and having an interior volume in the desired shape, is filled with photomonomer resin. The material for the transparent portion of the mold is selected to be a material that is index-matched to the photomonomer resin. The filled mold, placed into a bath of transparent fluid index-matched to the transparent portion of the mold, and illuminated, from outside the fluid, through a photomask, with collimated light. The collimated light travels through the photomask forming beams of light that enter the transparent fluid, propagate into the mold, and form a micro-truss structure in the shape of the interior volume of the mold. The micro-truss structure may then be removed from the mold, or part or all of the mold may be left adhered to the micro-truss structure, forming covering face sheets.

Abstract: This disclosure enables direct 3D printing of preceramic polymers, which can be converted to fully dense ceramics. Some variations provide a preceramic resin formulation comprising a molecule with two or more C?X double bonds or C?X triple bonds, wherein X is selected from C, S, N, or O, and wherein the molecule further comprises at least one non-carbon atom selected from Si, B, Al, Ti, Zn, P, Ge, S, N, or O; a photoinitiator; a free-radical inhibitor; and a 3D-printing resolution agent. The disclosed preceramic resin formulations can be 3D-printed using stereolithography into objects with complex shape. The polymeric objects may be directly converted to fully dense ceramics with properties that approach the theoretical maximum strength of the base materials. Low-cost structures are obtained that are lightweight, strong, and stiff, but stable in the presence of a high-temperature oxidizing environment.

Abstract: This disclosure enables direct 3D printing of preceramic polymers, which can be converted to fully dense ceramics. Some variations provide a preceramic resin formulation comprising a molecule with two or more C?X double bonds or C?X triple bonds, wherein X is selected from C, S, N, or O, and wherein the molecule further comprises at least one non-carbon atom selected from Si, B, Al, Ti, Zn, P, Ge, S, N, or O; a photoinitiator; a free-radical inhibitor; and a 3D-printing resolution agent. The disclosed preceramic resin formulations can be 3D-printed using stereolithography into objects with complex shape. The polymeric objects may be directly converted to fully dense ceramics with properties that approach the theoretical maximum strength of the base materials. Low-cost structures are obtained that are lightweight, strong, and stiff, but stable in the presence of a high-temperature oxidizing environment.

Abstract: Ignition-quenching systems comprise an ignition-quenching cover configured to quench an ignition event in a combustible environment triggered by an ignition source associated with a fastener stack. The ignition-quenching cover comprises a porous body that is gas permeable and that has pores sized to quench ignition in the combustible environment. The ignition-quenching cover further comprises a cover attachment feature configured to mate with a fastener attachment feature of the fastener stack. The ignition-quenching cover is configured to cover the fastener stack, which may be associated with a potential ignition source that produces an ignition event in the combustible environment. The porous body may include one or more porous elements that may be formed of various polymeric, mesh, or fabric materials. The ignition-quenching cover may comprise a non-porous frame that is bonded to the porous body and that defines the cover attachment feature.

Abstract: Methods of manufacturing a structure having at least one plated region and at least one unplated region. The method includes plating a metal on a polymer structure having a first region accepting the metal and a second region unreceptive to the metal plating. The first region may include fully-cured polymer optical waveguides and the second region may include partially-cured polymer optical waveguides. The first region may include a first polymer composition and the second region may include a second polymer composition different than the first polymer composition.

Abstract: Resins for 3D printing of a preceramic composition loaded with a solid polymer filler, followed by converting the preceramic composition to a 3D-printed ceramic material, are described. Some variations provide a preceramic composition containing a radiation-curable liquid resin formulation and a solid polymer filler dispersed within the liquid resin formulation. The liquid resin formulation is compatible with stereolithography, UV curing, and/or 3D printing. The solid polymer filler may be an organic polymer, an inorganic polymer, or a combination thereof. The solid polymer filler may itself be an inorganic preceramic polymer, which may have the same composition as a polymerized variant of the liquid resin formulation, or a different composition. Many compositions are disclosed as options for the liquid resin formulation and the solid polymer filler.

Abstract: An aperture system for a bottom-up stereolithography device including a reservoir having a lower opening, an aperture including a flexible membrane positioned within the reservoir and covering the lower opening, and a boundary seal positioned around a periphery of the flexible membrane, the boundary seal including one or more boundary seal components and immobilizing the periphery of the flexible membrane against the reservoir. The flexible membrane is formed of a material having a low affinity for a liquid resin used in the stereolithography device as well as cured photopolymer resin parts produced by the device. In addition, the flexible membrane is able to deform as the cured resin part is pulled away from the aperture, thus enabling lower energy mixed mode adhesive failure to occur at the interface between the cured resin and the aperture and reducing the chance of cohesive damage to the cured photopolymer part.

Abstract: In some variations, a polymer-based microlattice structure includes a plurality of intersecting micro-truss structural elements each comprising a thermoset first polymer, and a continuous coating layer (with a second polymer) that substantially encapsulates each of the micro-truss structural elements, wherein the second polymer in the continuous coating layer bonds the thermoset first polymer to a substrate. The micro-truss structural elements preferably are architecturally ordered and the coating layer is uniformly distributed within the microlattice structure. The polymer coating layer may be present over the entire microlattice surface area, thereby increasing bond area to improve toughness. The microlattice structure may also have higher glass-transition temperature and chemical resistance, compared to a microlattice structure without the coating layer. Methods of forming a polymer-based microlattice structure are also disclosed.

Abstract: This invention provides resin formulations which may be used for 3D printing and pyrolyzing to produce a ceramic matrix composite. The resin formulations contain a solid-phase filler, to provide high thermal stability and mechanical strength (e.g., fracture toughness) in the final ceramic material. The invention provides direct, free-form 3D printing of a preceramic polymer loaded with a solid-phase filler, followed by converting the preceramic polymer to a 3D-printed ceramic matrix composite with potentially complex 3D shapes or in the form of large parts. Other variations provide active solid-phase functional additives as solid-phase fillers, to perform or enhance at least one chemical, physical, mechanical, or electrical function within the ceramic structure as it is being formed as well as in the final structure. Solid-phase functional additives actively improve the final ceramic structure through one or more changes actively induced by the additives during pyrolysis or other thermal treatment.

Abstract: This invention provides resin formulations which may be used for 3D printing and pyrolyzing to produce a ceramic matrix composite. The resin formulations contain a solid-phase filler, to provide high thermal stability and mechanical strength (e.g., fracture toughness) in the final ceramic material. The invention provides direct, free-form 3D printing of a preceramic polymer loaded with a solid-phase filler, followed by converting the preceramic polymer to a 3D-printed ceramic matrix composite with potentially complex 3D shapes or in the form of large parts. Other variations provide active solid-phase functional additives as solid-phase fillers, to perform or enhance at least one chemical, physical, mechanical, or electrical function within the ceramic structure as it is being formed as well as in the final structure. Solid-phase functional additives actively improve the final ceramic structure through one or more changes actively induced by the additives during pyrolysis or other thermal treatment.

Abstract: This invention provides resin formulations which may be used for 3D printing and pyrolyzing to produce a ceramic matrix composite. The resin formulations contain a solid-phase filler, to provide high thermal stability and mechanical strength (e.g., fracture toughness) in the final ceramic material. The invention provides direct, free-form 3D printing of a preceramic polymer loaded with a solid-phase filler, followed by converting the preceramic polymer to a 3D-printed ceramic matrix composite with potentially complex 3D shapes or in the form of large parts. Other variations provide active solid-phase functional additives as solid-phase fillers, to perform or enhance at least one chemical, physical, mechanical, or electrical function within the ceramic structure as it is being formed as well as in the final structure. Solid-phase functional additives actively improve the final ceramic structure through one or more changes actively induced by the additives during pyrolysis or other thermal treatment.

Abstract: Architected materials with superior energy absorption properties when loaded in compression. In several embodiments such materials are formed from micro-truss structures composed of interpenetrating tubes in a volume between a first surface and a second surface. The stress-strain response of these structures, for compressive loads applied to the two surfaces, is tailored by arranging for some but not all of the tubes to extend to both surfaces, adjusting the number of layers of repeated unit cells in the structure, arranging for the nodes to be offset from alignment along lines normal to the surfaces, or including multiple interlocking micro-truss structures.

Abstract: Architected materials with superior energy absorption properties when loaded in compression. In several embodiments such materials are formed from micro-truss structures composed of interpenetrating tubes in a volume between a first surface and a second surface. The stress-strain response of these structures, for compressive loads applied to the two surfaces, is tailored by arranging for some but not all of the tubes to extend to both surfaces, adjusting the number of layers of repeated unit cells in the structure, arranging for the nodes to be offset from alignment along lines normal to the surfaces, or including multiple interlocking micro-truss structures.

Abstract: Branched hierarchical micro-truss structures may be incorporated into energy-absorbing structures to exhibit a tailored multi-stage buckling response to a range of different compressive loads. Branched hierarchical micro-truss structures may also be configured to function as vascular systems to deliver fluid for thermal load management or altering the aerodynamic properties of a vehicle or structure into which the branched hierarchical micro-truss structure is incorporated. The branched hierarchical micro-truss structure includes a first layer having a series of interconnected struts and a second layer having a series of struts branching outward from an end of each of the struts in the first layer.

Abstract: A multi-chemistry structure includes: a plurality of interconnected polymer struts arranged in a lattice; a first layer of the lattice including a first array of first unit cells; a second layer of the lattice including a second array of second unit cells; at least one region of the lattice being formed of a first polymer; and at least one region of the lattice being formed of a second polymer different from the first polymer.