Abstract: An improved method for obtaining high fiber volume fraction, long fiber injection molded articles is provided. According to one embodiment, the method includes forming an injection molding feedstock by cutting pre-impregnated fiber-reinforced tape into platelets. The platelets can be coated with a thin layer of polymer to allow sliding of the platelets with respect to each other at the early stages of plastication, rather than forcing relative motion of fibers with respect to each other. The method can further include the dispersion of material only in the final stages of the injection molding screw to promote gentle motion of the feedstock at the earlier stages of the plastication process. The method allows improvement of mechanical properties of articles manufactured with equipment and techniques that are prevalent in high volume automotive and consumer industries.

Abstract: An assembly for additive manufacturing includes a build housing including a base, a print head, and a print head support connected to the base for supporting the print head above the base. A driver system is provided for moving the print head and the base relative to one another. A build platform comprising a build support and at least one platen. The build support can be detachably engageable to the housing. The platens can be detachably engageable to the build support. The build support can include registration structure for registering the position of the build support relative to the build housing. A method of additive manufacturing is also disclosed.

Abstract: A method for producing magnet-polymer pellets useful as a feedstock in an additive manufacturing process, comprising: (i) blending thermoplastic polymer and hard magnetic particles; (ii) feeding the blended magnet-polymer mixture into a pre-feed hopper that feeds directly into an inlet of a temperature-controlled barrel extruder; (iii) feeding the blended magnet-polymer mixture into the barrel extruder at a fixed feed rate of 5-20 kg/hour, wherein the temperature at the outlet is at least to no more than 10° C. above a glass transition temperature of the blended magnet-polymer mixture; (iv) feeding the blended magnet-polymer mixture directly into an extruding die; (v) passing the blended magnet-polymer mixture through the extruding die at a fixed speed; and (vi) cutting the magnet-polymer mixture at regular intervals as the mixture exits the extruding die at the fixed speed. The use of the pellets as feed material in an additive manufacturing process is also described.

Abstract: A system and method for improving additive manufacturing, including additive manufacturing toolpaths, is provided. The system and method includes a toolpath generator that obtains initial toolpaths of an object, identifies isolated paths in the toolpaths, and adds bridge connections between neighboring isolated paths in each layer to improve the toolpaths. The bridge connections facilitate the continuous and non-stop deposition of each layer according to improved toolpaths during additive manufacture, which can reduce total deposition time and improve the resultant additive manufacture.

Abstract: A structural health monitoring method is provided that utilizes self-sensing printed polymer structures. The method is based on resistivity properties of conductive materials, which can be integrated to a 3D printed polymer structure during additive manufacturing. An article to be monitored has at least one 3D printed polymer structure including a circuit comprising at least one conductive pathway extending through a non-conductive material. The resistance across the circuit is measured during or after loading of the article to determine a resistance value. The measured resistance value is compared to a known resistance value, and based on the comparison, a defect can be detected in the 3D printed polymer structure. Structural health monitoring systems and articles with integrated structural health monitoring are also provided.

Abstract: A method for rapid manufacturing of three dimensional discontinuous fiber preforms is provided. The method includes the deposition of a polymeric material containing fibers on a surface to form a tailored charge for compression molding. The reinforced polymeric material may be a thermoplastic or a reactive polymer with viscosity low enough to allow flow through an orifice during deposition, yet high enough zero shear viscosity to retain the approximate shape of the deposited charge. The material can be deposited in a predetermined pattern to induce the desired mechanical properties through alignment of the fibers. This deposition can be performed in a single layer or in multiple layers. The alignment is achieved passively by shear alignment of the fibers or actively through fiber orientation control or mixing. The fibers can be of the desired material, length, and morphology, including short and long filaments.

Abstract: A method of forming a low-density three-dimensional article is provided. The method includes printing a low-density composition on a substrate to form at least one layer comprising the low-density composition. The low-density composition includes a (P) polymer component and (M) a microsphere component in a ratio by volume (P):(M). The method also includes selectively controlling a density of the low-density composition during printing to give the at least one layer on the substrate. Selectively controlling the density of the low-density composition includes varying the ratio (P):(M) during printing. The method further includes repeating the printing and selectively controlling the density of the low-density composition to form additional layer(s), thereby forming the low-density three-dimensional article. A low-density three-dimensional article prepared in accordance with the method is also provided.

Abstract: An apparatus and device for creating a vertical strengthening feature within a 3D printed article of manufacture for improving mechanical performance in the Z-direction. Fill material is deposited in voids vertically crossing multiple layers during the build of 3D printing. The device includes a penetrating extension that fits within the void to create a vertical strengthening feature via heat and/or extruded fill material. The size and/or movement of the heated extension can impact the void side walls to reflow the build material and blend the layers together within the void side walls.

Abstract: A method for producing a polymer composite fiber comprised of a polymer matrix with filaments incorporated therein whose lengthwise dimensions are substantially oriented with the axial dimension of the composite fiber, the method comprising subjecting a melt comprised of a polymer matrix and filaments to an extrusion process in which the melt is extruded into a fibrous form in the absence of screw extruders and in the substantial absence of shear forces that result in breakage of the filaments, followed by cooling and solidification of the extruded melt to provide the polymer composite fiber. Integration of these polymer composite fibers with additive manufacturing technologies, particularly rapid prototyping methods, such as FFF and 3D printing, are also described. The resulting polymer composite fibers and articles made thereof are also described.

Abstract: A method and apparatus for additive manufacturing that includes a nozzle and/or barrel for extruding a plastic material and a supply of polymeric working material provided to the nozzle, wherein the polymeric working material is magnetically susceptible and/or electrically conductive. A magneto-dynamic heater is provided for producing a time varying, high flux, frequency sweeping, alternating magnetic field in the vicinity of the nozzle to penetrate into and couple the working material to heat the material through at least one of an induced transient magnetic domain and an induced, annular current.

Abstract: An additive manufacturing method and component having a fill layer material injected into voids as a Z-direction liquid nail or pin to provide a better connection between layers. Rather than depositing a complete layer, the extruder stops extruding at certain sections of the layers to leave a void. This repeats in the same location for the next predetermined number of layers, to create a series of vertically aligned voids in the print. Once the void hole is deep enough, the extruder will go back to this hole after completing the layer and fill it in. When this is done, the material flows down to the bottom of the hole and fill in the hole until it reaches the level of the most recent layer. This can be done a plurality of times on each layer.

Abstract: A manufactured component, method and apparatus for advanced manufacturing that includes a polymeric working material formed into a mandrel with a carbon fiber overlay formed in a continuation of the process. The mandrel build and the carbon fiber overlay of the component preferably take place at atmospheric temperatures.

Abstract: A method for producing a bonded permanent magnet, comprising: (i) incorporating a solid precursor material comprising a thermoplastic crosslinkable polymer and magnetic particles into an additive manufacturing device, wherein the crosslinkable polymer has a delayed crosslinking ability; (ii) melting the precursor material by heating it to a temperature of at least and no more than 10° C. above its glass transition temperature; (iii) extruding the melt through the additive manufacturing device and, as the extrudate exits from the nozzle and is deposited on a substrate as a solidified preform of a desired shape, exposing the resultant extrudate to a directional magnetic field of sufficient strength to align the magnetic particles; and (iv) curing the solidified preform by subjecting it to conditions that result in crosslinking of the thermoplastic crosslinkable polymer to convert it to a crosslinked thermoset. The resulting bonded permanent magnet and articles made thereof are also described.

Abstract: A method for producing magnet-polymer pellets useful as a feedstock in an additive manufacturing process, comprising: (i) blending thermoplastic polymer and hard magnetic particles; (ii) feeding the blended magnet-polymer mixture into a pre-feed hopper that feeds directly into an inlet of a temperature-controlled barrel extruder; (iii) feeding the blended magnet-polymer mixture into the barrel extruder at a fixed feed rate of 5-20 kg/hour, wherein the temperature at the outlet is at least to no more than 10° C. above a glass transition temperature of the blended magnet-polymer mixture; (iv) feeding the blended magnet-polymer mixture directly into an extruding die; (v) passing the blended magnet-polymer mixture through the extruding die at a fixed speed; and (vi) cutting the magnet-polymer mixture at regular intervals as the mixture exits the extruding die at the fixed speed. The use of the pellets as feed material in an additive manufacturing process is also described.

Abstract: A method for producing a bonded permanent magnet by additive manufacturing, comprising: (i) incorporating components of a solid precursor material into at least one deposition head of at least one multi-axis robotic arm of a big area additive manufacturing (BAAM) system, the components of the solid precursor material comprising a thermoplastic polymer and hard magnetic powder; said deposition head performs melting, compounding, and extruding functions; and said BAAM system has an unbounded open-air build space; and (ii) depositing an extrudate of said solid precursor material layer-by-layer from said deposition head until an object constructed of said extrudate is formed, and allowing the extrudate to cool and harden after each deposition, to produce the bonded permanent magnet. The resulting bonded permanent magnet and articles made thereof are also described.

Abstract: An additive manufacturing machine includes a nozzle assembly with a noncircular, rotatable outlet. The nozzle assembly deposits a bead of material having a width that is defined by the angular orientation of the noncircular shaped outlet with respect to the material deposition path direction. The combination of high material deposition rate and fine resolution save time and energy while also producing high-quality parts.

Abstract: Several examples of additive manufacturing machines and methods for depositing a bead of composite polymer material having continuous fiber reinforcement are disclosed. A length of fiber reinforcement is provided to a nozzle. The fiber reinforcement is embedded into a stream of a base polymer material at the nozzle and deposited as a bead of composite polymer material having fiber reinforcement. The fiber reinforcement may be dry or pre-impregnated with a reinforcing polymer. The additional strength of the composite polymer material having fiber reinforcement allows for true, three-dimensional printing of articles having unsupported regions.

Abstract: Several examples of an article of manufacture made with an additive manufacturing machine are disclosed. A length of fiber reinforcement is provided to a nozzle. The fiber reinforcement is embedded into a stream of a base polymer material at the nozzle and deposited as a bead of composite polymer material having fiber reinforcement. The fiber reinforcement may be dry or pre-impregnated with a reinforcing polymer. The additional strength of the composite polymer material having fiber reinforcement allows for true, three-dimensional printing of articles having unsupported regions.

Abstract: Methods and compositions for additive manufacturing that include reactive or thermosetting polymers, such as urethanes and epoxies. The polymers are melted, partially cross-linked prior to the depositing, deposited to form a component object, solidified, and fully cross-linked. These polymers form networks of chemical bonds that span the deposited layers. Application of a directional electromagnetic field can be applied to aromatic polymers after deposition to align the polymers for improved bonding between the deposited layers.

Abstract: A manufactured component, method and apparatus for advanced manufacturing that includes a nozzle for extruding a working material, wherein the polymeric working material includes a carbon fiber reinforced polymer. The build of the component takes place on a work surface at atmospheric temperatures.