Fully Automated High-Throughput Additive Manufacturing

manufacturing
Fully Automated High-Throughput Additive Manufacturing (TOP2-301)
Embedding Smart Code to Automate and Augment 3D Printing Processes
Overview
The Additive Manufacturing (AM) process uses a 3D printer to convert a filament into a three-dimensional manufactured object by melting the filament and depositing it in built-up layers to form the desired object, where the movement of the printing head is controlled by computer code. The automation of AM is limited and usually still requires human labor workflows, including the fundamental step of removing the finished object from the printer platform. NASA Ames Research Center has developed a novel method to increase automation of AM by embedding additional instructions into the manufacturing toolpath to create manufacturing tools in situ, such as linear springs on the printer platform, and to instruct movement of the printers parts to autonomously move the finished object off the platform. The technology eliminates the need for humans in the loop for high-throughput applications. Testing can also be integrated into the manufacturing toolpath.

The Technology
The technology is a method to increase automation of Additive Manufacturing (AM) through augmentation of the Fused Filament Fabrication (FFF) process. It can significantly increase the speed of 3D printing by automating the removal of printed components from the build platform without the need for additional hardware, which increases printing throughput. The method can also be leveraged to perform automated object testing and characterization. The method includes embedding into the manufacturing instructions methods to fabricate directly onto the build platform an actuator tool, such as a linear spring. The deposition head can be leveraged as a robotic manipulator of the actuator tool to bend, cock, and release the linear spring to strike the target manufactured object and move it off the build platform of the machine they were manufactured on. The ability for an object to 'fly off of the machine that made it' essentially enables automated clearing of the processed build volume. The technology can also be used for testing the AM machine or the feedstock material by successively fabricating prototypes of the manufactured object, and taking measurements from sensors as the actuator strikes the prototype. This provides automated testing for quality control, machine calibration, material origins, and counterfeit detection.
Printer rendering AM Throughput Comparison &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp System Process Flow
Benefits
  • Ability to 3D-print objects, and autonomously move the finished object off the 3D printer platform
  • Economic - the increased throughput through the automation of clearing a machine without the need for additional robotic manipulators
  • Ability to automatically test 3D-printed objects without human intervention
  • Automated testing for quality control, machine calibration, material origin, counterfeit detection
  • Portable - ease of implementation on many widely used Fused Filament Fabrication (FFF) platforms with minimal tailoring
  • Allow for the automated embedding and physical validation of additional dimensions of information through the manufacturing process

Applications
  • Automated Additive Manufacturing object testing and material testing and rapid prototyping
  • 3D printer end-users requiring precise physical characteristics of printed components (e.g., automotive, urban air mobility industries)
  • 3D printing service providers
  • 3D printing platform manufacturers
  • Computer-aided manufacturing (CAM) systems
  • In-Space Manufacturing and Testing
Technology Details

manufacturing
TOP2-301
ARC-18452-1 ARC-18748-1
https://ieeexplore.ieee.org/abstract/document/9158926
Similar Results
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Additive Manufacturing Model-based Process Metrics (AM-PM)
Modeling additive manufacturing processes can be difficult due to the scale difference between the active processing point (e.g., a sub-millimeter melt pool) and the part itself. Typically, the tools used to model these processes are either too computationally intensive (due to high physical fidelity or inefficient computations) or are focused solely on either the microscale (e.g., microstructure) or macroscale (e.g., cracks). These pitfalls make the tools unsuitable for fast and efficient evaluations of additive manufacturing build files and parts. Failures in parts made by laser powder bed fusion (L-PBF) often come when there is a lack of fusion or overheating of the metal powder that causes areas of high porosity. AM-PM uses a point field-based method to model L-PBF process conditions from either the build instructions (pre-build) or in situ measurements (during the build). The AM-PM modeling technique has been tested in several builds including a Ti-6Al-4V test article that was divided into 16 parts, each with different build conditions. With AM-PM, calculations are performed faster than similar methods and the technique can be generalized to other additive manufacturing processes. The AM-PM method is at technology readiness level (TRL) 6 (system/subsystem model or prototype demonstration in a relevant environment) and is available for patent licensing.
NASA's "Refabricator"
Recyclable Feedstocks for Additive Manufacturing
NASA's new technique for generating recyclable feedstocks for on-demand additive manufacturing employs the high-yield reversibility of the Diels-Alder reaction between maleimide and furan functionalities, utilizing the exceedingly favorable interaction between specific chemical functionalities, often termed "click reactions" due to their rapid rate and high efficiency. Integration of these moieties within a polymer coating on epoxy microparticle enables reversible assembly into macroscopic, free-standing articles. This click chemistry can be activated and reversed through the application of heat. Monomer species can be used to incorporate these functionalities into polyimide materials, which provide excellent mechanical, thermal, and electrical properties for space applications. Copoly (carbonate urethane) has been shown to be a viable coating material in the generation of polymer-coated epoxy microparticle systems and is amenable to being processed through a variety of approaches (e.g., filaments and slurries for 3D printing, compression molding, etc.). The polymeric materials are grown from the surfaces of in-house fabricated epoxy microparticles. The thermal and mechanical properties of the microparticles can be readily tuned by changes in composition. There are a number of potential applications for this NASA technology ranging from use of these materials for recyclable/repurpose-able articles (structural, decorative, etc.) to simple children's toys. More demanding uses such as for replacement parts in complex industrial systems are also possible. For long term space missions, it is envisioned that these feedstocks would be integrated into secondary spacecraft structures such that no additional concerns would be introduced due to in-space chemical reactions and no additional mass would be required.
James Webb Space Telescope deployed
Thin-Films with Integrated Structural and Functional Elements
The technology uses additive print manufacturing to produce hierarchical and integrated structural and functional elements into large-area thin-film structures. Adding these structural and functional elements has the potential to enable very lightweight, large-scale thin-films with improved damage tolerance, self-deployment capability, flexibility, and multifunctional (optical, thermal, electrical) connectivity and interrogation capabilities. Based on simple and proven additive manufacturing concepts, advanced geometrical, biomimetic (insect wing), and hierarchical structures could be applied to, or eventually with further development integrated within the bulk of large-area thin films using roll-to-roll processing techniques for a potentially low-cost manufacturing approach. The subject technology potentially addresses many of the disadvantages of current large-scale membrane material systems, which are prone to damage or require extensive deployment and support structures.
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Interim, In Situ Additive Manufacturing Inspection
The in situ inspection technology for additive manufacturing combines different types of cameras strategically placed around the part to monitor its properties during construction. The IR cameras collect accurate temperature data to validate thermal math models, while the visual cameras obtain highly detailed data at the exact location of the laser to build accurate, as-built geometric models. Furthermore, certain adopted techniques (e.g., single to grouped pixels comparison to avoid bad/biased pixels) reduce false positive readings. NASA has developed and tested prototypes in both laser-sintered plastic and metal processes. The technology detected errors due to stray powder sparking and material layer lifts. Furthermore, the technology has the potential to detect anomalies in the property profile that are caused by errors due to stress, power density issues, incomplete melting, voids, incomplete fill, and layer lift-up. Three-dimensional models of the printed parts were reconstructed using only the collected data, which demonstrates the success and potential of the technology to provide a deeper understanding of the laser-metal interactions. By monitoring the print, layer by layer, in real-time, users can pause the process and make corrections to the build as needed, reducing material, energy, and time wasted in nonconforming parts.
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A One-piece Liquid Rocket Thrust Chamber Assembly
The one-piece multi-metallic composite overwrap thrust chamber assembly is centrally composed of an additively manufactured integral-channeled copper combustion chamber. The central chamber is being manufactured using a GRCop42 or GRCop84 copper-alloy additive manufacturing technology previously developed by NASA. A bimetallic joint (interface) is then built onto the nozzle end of the chamber using bimetallic additive manufacturing techniques. The result is a strong bond between the chamber and the interface with proper diffusion at the nozzle end of the copper-alloy. The bimetallic interface serves as the foundation of a freeform regen nozzle. A blown powder-based directed energy deposition process (DED) is used to build the regen nozzle with integral channels for coolant flow. The coolant circuits are closed with an integral manifold added using a radial cladding operation. To complete the TCA, the entire assembly including the combustion chamber and regen nozzle is wrapped with a composite overwrap capable of sustaining the required pressure and temperature loads.
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