Crack Prevention in 3D Printed Parts

3D printing method for automotive thin-walled parts with improved print quality and reduced risk of defects in complex shapes. The method involves dynamically adjusting the filling strategy based on the slope of the part contour. It calculates the slope of the contour lines and divides the part into areas with large and small slope changes. In areas with large slope, vertical filling is used, while in areas with small slope, parallel filling is used. This smooth transition avoids stress concentration points and reduces cracks and deformations.

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3D printing thin-walled parts with reduced internal stress and warpage using a support structure with thermal conductivity. The method involves printing thin-walled parts with a thermally conductive member like columns or ribs adjacent to the walls. This provides a path for heat to dissipate during printing, reducing internal stress and warpage compared to just printing the thin walls alone. The thermally conductive member connects to the walls using a cellular rib structure for stability. The thermally conductive member can also connect to hollow supports for additional heat dissipation.

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3D printing metal parts without support structures to reduce cost and time compared to traditional methods. The key is designing a transition layer that gradually reduces the angle between the part and the build plate as it approaches overhanging features. This prevents the part from collapsing during printing. The transition layer is part of the printed part and not removable. The angle of the transition layer is adjusted based on the overhang angle to avoid failure.

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Endothermic inkjet 3D printing of parts using dynamic polymers that can self-heal after damage. The process involves printing with dynamic polymer powders and inks that contain reversible bonds. After printing, the parts are heated to promote further bonding and fill any voids, improving mechanical properties. The dynamic bonds also provide self-healing capability when the parts are damaged. This allows repairing cracks and extending part life. The dynamic polymers also enable shape memory functionality.

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Reducing residual stress in additive manufacturing by modifying the substrate design to weaken mechanical constraints during the printing process. The method involves creating slots or movable blocks perpendicular to the printing direction on the substrate. This allows local sliding of the blocks during printing instead of full material contraction, converting some plastic deformation into elastic deformation. This reduces plastic strain accumulation and suppresses residual stress formation compared to conventional printing on solid substrates.

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Ultrasonic additive manufacturing system for joining and repairing metal structures using a contoured sonotrode that rotates and translates to reduce defects when welding metal foils. The contoured welding surface profile prevents cracks and weak spots in the welds when joining or repairing metal parts. The contour eliminates interfaces normal to the weld direction, reducing defects compared to flat weld surfaces. The system involves positioning metal structures adjacent to each other, creating a contoured channel along the interface, and filling it with metal foils using the rotating and translating sonotrode for welding. This reduces cracking and weak points compared to conventional ultrasonic welding.

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3D printing metal objects without warping or cracking by using a tacky polymer substrate. The process involves spreading a layer of metal particles over a polymer substrate with low thermal conductivity and melting the unmasked metal with pulsed light to form each layer of the object. The polymer substrate reduces lateral heat transfer during melting, preventing warping and cracking.

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A method to homogenize the microstructure of additive manufacturing components to mitigate thermal accumulation effects during 3D printing. The method involves using multi-physics coupling to simulate and control the temperature, stress, and microstructure evolution in the printing process. It allows predicting and preventing defects like porosity, cracks, and impurities by optimizing printing parameters based on the simulation results. This helps improve the microstructure and mechanical properties of 3D printed parts compared to experimental methods.

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This method reduces microcracking in additively manufacturing superalloys like nickel-based alloys by using a mixture of high-melt and low-melt superalloy powders. The low-melt powder has a lower solidus temperature than the high-melt powder. When combined in the right ratios, this powder mixture reduces cracking during additive manufacturing compared to using only the high-melt powder.

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A nickel-based superalloy composition for use in selective laser melting (SLM) to enable crack-free processing of Ni-based superalloys with high gamma prime content. The alloy composition contains a minimum of 1.2 wt % Hafnium and has a Hf/C atomic ratio >1.55.

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Body-mounted components like orthoses have improved flexibility and resistance to breakage when bent. The components are made by 3D printing using a resin material with high elongation at break when stretched. This elongation property allows the 3D-printed parts to bend and stretch without breaking.

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Reducing geometric distortions and defects in 3D printed objects made by powder-bed binder jetting 3D printers. The method involves compensating for dimensional variations and defects due to consolidation of the powder during printing. It involves modeling the consolidation behavior of the powder and composite material in the build chamber to predict how the object will deform during printing. This allows generating a compensated object model that accounts for the anticipated distortions and weaknesses. The compensated model is then used to print the object with reduced distortions and defects compared to printing the original model. The consolidation modeling takes into account factors like powder properties, binder drop size, and object geometry.

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Steel material for additive manufacturing of tools with excellent mechanical properties and resistance to cracking without preheating. The steel composition contains 0.3-0.6% carbon, 3.5-12% chromium, 0.5-4% molybdenum, and 0-3% nickel, with the sum of chromium and molybdenum being 4-16%.

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Ultrasonic additive manufacturing system using a contoured sonotrode to minimize cracking and weak areas when joining and repairing metal structures. The system has a rotating sonotrode with a welding surface that is contoured, such as V-shaped or curved. The contoured profile allows the sonotrode to eliminate interfaces normal to the weld direction, reducing defects. When joining or repairing metal structures, channels with matching contoured profiles are created. Metal foils are then welded into the channels using the sonotrode. This reduces cracking and weak areas compared to conventional flat sonotrodes.

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Laser additive manufacturing methods for high-strength aluminum alloys that suppress residual stress cracking. The methods involve modifying laser scanning parameters like speed, power, and scan path to reduce solidification strain during additive manufacturing.

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3D printing method for large section parts using selective laser melting (SLM) technology that prevents warping and cracking of printed parts with large cross-sections. The method involves scanning large planes by filling and scanning after first scanning a grid pattern. The grid pattern is scanned with a thinner frame than the final part size. This allows heat to conduct more quickly between the grid frames during filling and scanning, preventing excessive heat accumulation. It also balances the shrinkage stresses during cooling and solidification. By scanning the grid first and filling in between, it improves dimensional accuracy and reduces warping and cracking in large section 3D printed parts.

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Additive manufacturing of gas turbine components with internal tunable auxetic structures to mitigate cracking. The internal structures are made from a repeating pattern of interconnected 3D auxetic unit cells. The unit cell is made from intersecting dimpled sheets that exhibit negative Poisson's ratio behavior. This enables the internal structure to contract instead of expand when heated, reducing stresses that can cause cracking. The auxetic structure can be additively manufactured with the component to avoid stress concentrations from separate supports.

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Reducing deformation of 3D printed objects during curing by automatically generating and printing additional sacrificial parts to provide mechanical support. The technique involves analyzing the 3D model before printing to identify areas that will likely deform during curing due to airflow. If deformation is predicted, additional object models are generated and printed alongside the main object to provide extra support during curing. This helps prevent deformation without modifying the curing process.

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A 3D printing method that reduces porosity and improves the strength of printed parts by using nozzles with non-circular cross-sections. The method involves optimizing the shape of the nozzle holes using computer modeling and simulations to minimize porosity and maximize strength compared to circular nozzles. The optimized nozzles have shapes like trapezoids and inverted trapezoids that extrude filament in a way that reduces voids and improves mechanical properties in the printed parts.

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Compensating for deformation of thin rod-like porous structures in 3D printing by using a life-death element method. The method involves killing all units to be printed by multiplying them by a very small factor like 1e-9. This simulates deformation and allows compensating for the actual deformation when the part is printed. The killing factor is chosen to be much smaller than the expected deformation amount. This way, the killing step roughly approximates the deformation and the final printed part will have compensated deformation closer to the desired shape.

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