Powder Recovery in Additive Manufacturing

Recirculation system for 3D printing powder beds to reduce waste and improve print quality. The system has a powder delivery path from the tank, a repository to store excess powder, and a recirculation path returning powder from the repository to the delivery path. This allows reusing excess powder from the build area instead of discarding it. The recirculation path can have an agitator to mix powder. The delivery and recirculation paths can have heaters. The recirculation system can also include a powder return slot on the build platform to capture excess powder and return it.

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Method and apparatus for efficiently separating additively manufactured components from powder cakes for reuse. The method involves transferring the powder cake into an enclosure and vibrating it solely in the vertical direction using a vibration generator. This breaks up the cake, de-agglomerates fragments, pulverizes adhering powder, and fluidizes the powder. By controlling vibration frequency and amplitude adapted to the cake properties, the process phases are carried out effectively. The apparatus has a transfer station, de-powdering station with vertical oscillator, and processing station to mix and reuse powder.

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Device for recycling selective laser melting (SLM) gradient powders to enable recycling of gradient metal powders used in SLM additive manufacturing without mixing and adhesion of different powders. The device has features like an ultrasonic powder suction device, vertical support frame, screening device, waste material recovery device, powder conveying pipe, cooling device, and controller. It operates in vacuum to reduce contact with air, uses a metal powder sensor to automatically identify powders, and a cooling device to prevent explosions. This allows separating, screening, and recycling of gradient powders without manual intervention.

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The performance and durability of proton-exchange membrane fuel cells (PEMFCs) are dependent on flow, humidifying water, outgoing water management. Unlike conventional flow fields with linear channels, the complex 3D fieldfeaturing repeating baffles along channel, known as baffle designinduces a micro-scale interface flux between gas diffusion layer (GDL) fields. Thus, an intensive oxygen is created that removes excess from GDL, thereby improving cell efficiency. Another approach for channel design Turing field, which resembles organization fluid flows in natural objects such leaves, lungs, blood system. This enhances distribution inlet significantly compared traditional designs. present study aims to combine advantages both field designs provide model investigations influence mixed efficiency PEMFCs. It was established achieves highest electrode current density 1.2 A/cm2, outperforming other Specifically, it 20% improvement over design, reaching 1.0 A/cm2 generating three times more than delivers 0.4 A/cm2. In contrast, serpentine exhibit lowest density. provides better utiliz... Read More

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<div class="section abstract"><div class="htmlview paragraph">The utilization of hydrogen in low-temperature Proton Exchange Membrane Fuel Cells (PEMFCs) stands out as a compelling prospect for driving widespread shift towards green industry practices. Despite significant advancements, comprehensive understanding water behaviour and dynamics within PEMFCs remains crucial their extensive integration propulsion applications. Striking delicate balance between flooding drying conditions poses challenge achieving stable efficient PEMFC operation. In this study, preliminary experimental investigation was conducted focusing on carbon-paper Gas Diffusion Layer (GDL) gas channel walls. The static, advancing receding contact angles were measured utilized boundary simulations. influence membrane humidity also examined during the campaign. 3D CFD simulations performed straight portion with selected domain length 5 mm section 1x1 mm. Two classes droplets (0.05 mm<sup>3</sup> 0.075 mm<sup>3</sup>) deposited middle double GDL wall. To account difference angles, r... Read More

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Dual direction flow restrictor that prevents debris from clogging the orifice while allowing easy removal of debris introduced during additive manufacturing. The flow restrictor has two flowbody sections, one with slots and a larger diameter section that expands the other section when coupled. This allows debris to be easily removed from the expanded section during manufacturing, preventing clogging of the orifice. In the assembled flow restrictor, the smaller section with slots is received inside the larger section's counterbore.

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A device for cleaning 3D-printed components from adhering powder particles without manual intervention. The device uses a vacuum chamber with a movable component carrier that can be inserted and removed through a pressure-tight door. Inside the chamber, a platform moves in multiple axes to receive the 3D-printed part. Tubular supply lines in the chamber walls generate a volumetric flow when closed. The component carrier and chamber are connected to a negative pressure system. This vacuum pulls the adhering powder particles off the component as it moves inside the chamber. The removed powder is collected in hoppers and sent to a separation system.

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Recyclable resins for 3D printing that can be reground and remade into new 3D printing resins. The recycling process involves grinding or melting printed parts to make a reactive particulate material. This is mixed with additional blocking agents and diluents, then heated to reform a homogeneous solution. Additional photoinitiator, light absorber, etc. are added to make a new printable resin from the recycled material. This allows closed loop recycling of 3D printed objects.

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A process for removing ultrafine particles from atomized powder to improve flowability and other properties of the powder. The process involves contacting the atomized powder with a removal liquid, adding energy to the mixture to detach the ultrafine particles, and separating the removal liquid and detached ultrafine particles from the fine particles. This allows selectively removing the ultrafine particles without significantly impacting the fine particles. The separated ultrafine particles can be recycled back into the process. The resulting powder has improved flowability and other properties compared to the initial atomized powder.

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The accumulation of liquid water in the gas diffusion layer (GDL) and associated clogging reactant pathways are limiting factors for performance polymer electrolyte fuel cells (PEFC). design manufacturing GDLs with a deterministic pore space have potential to accelerate development next-generation PEFC an optimized balance between supply product removal. In this study, we explore tailored structures obtained from carbonization 3D-printed precursor. Three different GDL designs investigated by using operando X-ray radiography subsequent tomography track pathways. results confirm effectiveness designed features terms controlled percolation reveal trend toward vapor phase transport rather than away catalyst interface along strong convective flow within highly porous ordered structures.

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Proton Exchange Membrane Fuel Cells (PEMFCs) are considered a crucial technology for mitigating resource limitations and addressing environmental challenges. To improve the output power mass transfer characteristics of PEMFCs, this study developed three-dimensional (3D) model PEMFC with wedge-shaped flow field plate using computational fluid dynamics (CFD) methods. This focused on analyzing behavior thermal management reactants, as well investigating water removal capacity across different angular channel configurations. The results indicated that air intake modes combined channels affected within fuel cell. performance was most significantly when reaction gases flowed convectively. At tilt angle 18 voltage 0.25 V, maximum current density reached 1.9547 A/cm 2 , representing 24% increase compared to conventional parallel channel. Under these conditions, reactive were more uniformly distributed PEMFC. demonstrated new in generates high densities at larger angles lower voltages, improving oxygen distribution facilitating efficient liquid removal.

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A method for capturing excess powder from interior passages of additively manufactured parts using removable powder capture caps. The caps are designed with thin membranes that attach to the interior walls of the part during printing. After completion, the caps trap excess powder inside the part. To remove the caps, a tool engages a socket in the cap and twists it until the membrane breaks, allowing access to the powder.

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3D printing of metal objects using inkjet printing and selective powder deposition. The process involves printing a binder solution onto a substrate to create the object's shape layer by layer. Each layer is then coated with a metal powder. The excess powder is removed, leaving the metal selectively deposited in the printed shape. Challenges like oxidation of metal powders during melting are addressed using fluxes or melting in reducing atmospheres.

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Determining the exact amount of powder needed to 3D print a single object in a multi-object print job. This helps optimize powder usage and reduce waste when printing multiple objects together. The method involves calculating the volume of the printed object's outer layer (dilated object) based on the object's shape and the powder layer thickness. It also calculates the volumes of unused powder in the no-build and interstitial areas. Then, it determines the total lost powder based on recycling ratio and the calculated volumes. Finally, it calculates the required powder for the object by adding the used powder from the dilated object and the lost powder contribution.

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A powder removal system for 3D printing that effectively cleans the build platform without disturbing the printed part. The system has a blade to scrape excess powder from between layers without touching the part. Edge and central vacuum nozzles move with the blade to collect scraped powder without disturbing powder on adjacent areas. This allows precise removal of powder between layers without damaging the printed part.

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<div class="section abstract"><div class="htmlview paragraph">The interplay of electrochemistry, two-phase flow, and heat transfer generates complex transport phenomena within the porous materials fuel cells that are not yet fully understood. This lack comprehensive understanding complicates modeling liquid water transport, which is critical because hydration polymer electrolyte membrane significantly impacts cell performance. The mechanisms in media can be explained by capillary force, hydraulic permeation gravity effects, as well condensation evaporation. In general, mainly driven while body forces, such gravity, do affect its momentum. Due to limited experimental data on pressure saturation gas diffusion media, Leverett approach has been widely used for PEMFCs. a polynomial fitting imbibition unconsolidated sand packs. nature, this may accurately predict media. Fuel GDM materials, naturally hydrophilic, typically coated with nonwetting like polytetrafluoroethylene create hydrophobic surfaces pores. resulting nature intermediate wettability due coexistence hydrophilic p... Read More

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Creating a powder removal tool during additive manufacturing that can easily access and remove excess powder from inside complex parts with intricate internal passages. The tool is designed as a chain-like structure of interconnected links that can be simultaneously printed alongside the part. After completion, the tool is removed, forcing the powder out of the internal passages. Additional techniques like robotic appendages, vibration, air blasting, or media blasting can further clear remaining powder.

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Reusable metal powder for additive manufacturing that enables stable modeling and defect reduction when recycled. The powder contains an oxide film on the surface, with 0.015-0.106% oxygen content and a maximum oxide film thickness of 200 nm. This oxide layer reduces spattering during melting and prevents defects in recycled powder. The powder is reused in additive manufacturing by repeating melting and solidification steps. The oxygen level and oxide film thickness limits prevent oxide expansion and cracking issues in recycled powder.

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Automated powder removal from additively manufactured parts using a robotic depowdering system. The system has a depowdering station with a robot that grips the part, a nozzle to blow excess powder off, and a blower with an air curtain to contain the powder. This eliminates manual depowdering and allows automated transfer from the printing to sintering furnace.

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Automated system for depowdering and extracting 3D printed parts to simplify and streamline the post-processing steps. The system uses a removable container mounted on a linear actuator to raise and lower the printed layers. An internal apparatus with a sliding perforated plate depowders the layers. A gripper extracts the parts. This allows automated, layer-by-layer depowdering and part removal without manual intervention. The container can be swapped between print jobs.

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