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: Some variations provide a preceramic resin precursor formulation comprising: first molecules comprising at least one Si—N bond and/or at least one Si—C bond; and second molecules of the formula R4—N?C?O or R4—N?C?S, wherein R4 is a UV-active functional group. In some embodiments, R4 is selected from acrylate, methacrylate, vinyl ether, epoxide, oxetane, thiol, or a combination thereof. The first and second molecules are reacted with an isocyanate or isothiocyanate to form third molecules, providing a preceramic radiation-curable resin composition. The resin composition contains at least one Si—N bond and/or at least one Si—C bond in the main chain of the third molecules. Side chains of the third molecules may be selected from hydrogen, unsubstituted or substituted hydrocarbon groups, halides, esters, amines, hydroxyl, or cyano. The resin composition may be 3D printed and thermally treated to generate a ceramic material.

Abstract: Some variations provide a preceramic resin precursor formulation comprising: first molecules containing at least one Si—N bond and/or at least one Si—C bond; and second molecules of the formula R4—N?C?S, wherein R4 may be a UV-active functional group. In some embodiments, R4 is selected from ethynyl, vinyl, allyl, acrylate, methacrylate, vinyl ether, epoxide, oxetane, thiol, thioketone, isothiocyanate, or combinations thereof. The first and second molecules are reacted with an isothiocyanate to form third molecules, providing a preceramic radiation-curable resin composition. The resin composition contains at least one Si—N bond and/or at least one Si—C bond in the main chain of the third molecules. Side chains of the third molecules may be selected from hydrogen, unsubstituted or substituted hydrocarbon groups, halides, esters, amines, hydroxyl, or cyano. The resin composition may be 3D printed and thermally treated to generate a ceramic material.

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: This disclosure provides resin formulations which may be used for 3D printing and thermally treating to produce a ceramic material. The disclosure provides direct, free-form 3D printing of a preceramic polymer, followed by converting the preceramic polymer to a 3D-printed ceramic composite with potentially complex 3D shapes. A wide variety of chemical compositions is disclosed, and several experimental examples are included to demonstrate reduction to practice. For example, preceramic resin formulations may contain a carbosilane in which there is at least one functional group selected from vinyl, allyl, ethynyl, unsubstituted or substituted alkyl, ester group, amine, hydroxyl, vinyl ether, vinyl ester, glycidyl, glycidyl ether, vinyl glycidyl ether, vinyl amide, vinyl triazine, vinyl isocyanurate, acrylate, methacrylate, alkacrylate, alkyl alkacrylate, phenyl, halide, thiol, cyano, cyanate, or thiocyanate.

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: 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: 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 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: A system for fabricating composite parts efficiently. Pre-impregnated (prepreg) composite material is drawn as a sheet from a roll and fed by advancement rollers into a stamping and molding station in which a piece of the prepreg material is cut, on a mold, from the sheet. Pressure is applied to cause the prepreg material to conform to a surface of the mold, and the prepreg is cured with ultraviolet light. Additional layers of prepreg may be cut and cured on any layers that have already been cured on the mold. The complete part may be removed from the mold with ejector pins. Scrap prepreg may be recycled in a recycling station that separates reinforcing fiber from uncured resin.

Abstract: A method of manufacturing a sandwich structure having an open cellular core and a fluid-tight seal surrounding the core includes coupling a mold to a first facesheet to define a reservoir. The method also includes irradiating a volume of photo-monomer in the reservoir with a series of vertical collimated light beams to form a cured, solid polymer border extending around a periphery of the first facesheet. The method also includes irradiating a remaining volume of photo-monomer in the reservoir with a series of collimated light beams to form an ordered three-dimensional polymer microstructure core defined by a plurality of interconnected polymer optical waveguides coupled to the first facesheet and surrounded by the cured, solid polymer border. The method further includes coupling a second facesheet to the ordered three-dimensional microstructure core and the cured, solid polymer border to form the sandwich structure.

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: Some variations provide a process for fabricating a ceramic structure, the process comprising: producing a plurality of preceramic polymer parts; chemically, physically, and/or thermally joining the preceramic polymer parts together, to generate a preceramic polymer structure; thermally treating the preceramic polymer structure, to generate a ceramic structure; and recovering the ceramic structure. The process may employ additive manufacturing, subtractive manufacturing, casting, or a combination thereof. A composite overwrap may be applied to the preceramic polymer structure prior to pyrolysis, and the composite overwrap also pyrolyzes to a ceramic composite and is a part of the final ceramic structure. The ceramic structure may be silicon oxycarbide, silicon carbide, silicon nitride, silicon oxynitride, silicon carbonitride, silicon boronitride, silicon boron carbonitride, or boron nitride, for example.

Abstract: Some variations provide a curable resin formulation for a water-decomposable thermoset material, comprising: first molecules containing a boron-oxygen-silicon group and a first functional group that is reactive for free-radical, cationic, and/or hydrosilylation polymerization; optionally second molecules containing at least one second functional group that is reactive with the first molecules; and a polymerization initiator. Other variations provide a curable resin formulation comprising: first molecules containing a polyester group and a first functional group that is reactive for free-radical, cationic, and/or hydrosilylation polymerization; optionally second molecules containing at least one second functional group that is reactive with the first molecules; and a polymerization initiator.

Abstract: An interposer includes an interposer substrate having a series of vias, and a series of metallic interconnects in the series of vias. The interposer substrate has a first surface and a second surface opposite the first surface. The interposer substrate includes a dielectric material. A first pitch of the series of vias at a first end of the series of vias is different than a second pitch of the series of vias at a second end of the series of vias.

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: 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: 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 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.

Abstract: A ceramic micro-truss structure. In one embodiment green state polymer micro-truss structure is formed by exposing a photomonomer resin through a mask to collimated light from three or more directions. The green state polymer micro-truss structure is shaped and post-cured to form a cured polymer micro-truss structure. The cured polymer micro-truss structure is pyrolyzed to form a ceramic micro-truss structure, which may subsequently be coated with metal.