Isotropic Structure Creation in 3D Printing

High-throughput additive manufacturing of sintered parts with low anisotropy using dense feedstocks and selective patterning. The method involves 3D printing dense feedstocks with low porosity using a process like EHTAL (extremely high throughput additive manufacturing). To selectively form 3D parts from the dense feedstocks, a sintering ink is deposited on boundaries or negative spaces of a pattern. This inhibits sintering in those areas. When the parts are stacked and sintered, the unsintered regions remain unbound, defining the 3D part shape. This allows selective sintering of dense feedstocks without support materials.

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Additive manufacturing of large-scale 3D printed objects with improved mechanical properties in the stacking direction to address the issue of delamination between layers in large-scale additive manufacturing. The technique involves inserting reinforcement elements into the printed object during the build process. These reinforcement elements, like threaded rods, are inserted through the z-direction of the part and apply a compressive load to the layers. They distribute contact stresses and impose compressive stress in the layer direction to reinforce the printed part in multiple directions and tailor it to the specific geometry of the part. This provides reinforcement out of the z-direction that is needed for large-scale printed objects with complex geometry.

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Additively manufacturing shaped bodies like anatomic models with regions having different mechanical properties by site-selectively depositing thermoplastic and non-thermoplastic materials layer by layer. The method involves using a 3D printer with two print heads, one for thermoplastic material and one for non-thermoplastic material. The heads are moved independently to selectively deposit the materials in different regions to create shapes with varying mechanical properties. The non-thermoplastic material could be biocompatible materials like hydrogels or silicone rubbers to mimic soft tissues.

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3D printing of crystalline polymers with improved material properties and reduced printer wear compared to traditional methods. The process involves melting crystalline polymer in the print head, depositing layers, cooling rapidly to form amorphous regions, heat treating, and repeating. This avoids complete crystallization during printing, reduces stress accumulation, prevents deformation, and enables precise 3D printing of crystalline polymers without needing high temperatures. The cooled amorphous layers are bonded at lower temperatures than fully crystalline polymers. The cooled parts are then heat treated to relieve stress and prevent deformation.

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3D printing method for creating isotropic, high-strength 3D printed objects by using a printable composition with two thermoplastic polymers where one polymer has higher viscosity than the other under printing conditions. The higher viscosity polymer provides interlayer adhesion while the lower viscosity polymer enables easy extrusion. This combination results in objects with improved mechanical properties compared to using a single polymer with high viscosity. The higher viscosity polymer acts as a binder between layers while the lower viscosity polymer allows extrusion.

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A method for fabricating high performance 3D integrated composite structures using additive manufacturing that addresses the challenges of conventional 3D printing techniques to produce high-performance composites with good mechanical properties. The method involves alternately depositing layers of continuous fiber filaments and chopped fiber filaments with polymer. This provides a balanced fiber volume and polymer content in the layers to improve adhesion between adjacent layers and avoid dryness issues that can lead to defects and reduced strength. The alternating layers of continuous and chopped fibers also help align the fibers in different directions to better match the stress directions in the final part.

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Additively manufactured lattice structures with gradient density for optimized mechanical properties and reduced stress concentrations. The lattice structures are made of connectible unit cells with materials and voids. The materials occupy a portion of the cell volume, and the voids fill the rest. The unit cells form a lattice with smooth transitions between adjacent cells. The material thickness varies based on the location within the structure. This gradient density provides optimized properties by having lower-density areas in stress-free regions and higher-density areas in load-bearing regions. It allows tailoring the density distribution for applications like orthopedics where stresses vary. The gradients can be created using additive manufacturing techniques like 3D printing.

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3D printing method to produce dense parts with reduced porosity and internal voids. The method involves printing the initial layers of strands with narrow widths, then filling the gaps between them with wider strands. This allows complete filling of the gaps without overextruding. The narrow initial strands provide structure, while the wider fill strands densify the gaps. The extrusion rate and temperature can be different for the initial and fill strands.

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Coordinating curing, drying and sintering of materials with different properties in additive manufacturing to avoid issues like voids and dents in the printed object. The method involves identifying the material properties and quantifying the differences between them. It then modifies the 3D printing layer data based on these quantifications to operate the print head and curing devices appropriately for each material in each layer. This allows sequential printing of materials with different properties to avoid strains and defects from mismatched expansion/contraction during curing.

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