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NASA’s In Space Manufacturing Initiative (ISM): The Case for ISM - Why; ISM Path to Exploration; In Space Robotic Manufacturing and Assembly (IRMA). Additive Manufacturing (AM) Development For Liquid Rocket Engine Space Flight Hardware. MSFC (Marshall Space Flight Center) Standard and Specification For Additively Manufactured Space Flight Hardware.
Metal additive manufacturing (AM) is changing how complex aerospace parts are being designed and manufactured for rocket engines and launch vehicles. NASA has been leading AM efforts since the late 2000’s to mature specialty alloys for AM, advance AM processes, develop standards and infuse AM into rocket engines and the commercial supply chain. There are many types of AM processes and alloys in-use and this presentation will provide an overview of how NASA is applying these for rocket engines and the potential opportunities for AM in the future.
An overview of ceramic matrix composite (CMC) and additive manufacturing capabilities at GRC is provided. The additive manufacturing methods include laminated object manufacturing (LOM), binder jetting, 3-D printing, extrusion, direct writing and multi-materials additive manufacturing. Examples are given of GRC's extensive experience in the development and implementation of CMCs in various aerospace systems. Additive manufacturing offers significant advantages in fabricating preforms, ceramics, and CMCs. They will have to be selectively applied to "traditional" components but can also enable new applications. Additive manufacturing of lightweight and multifunctional polymer composites can provide wide ranging properties. Multi-material printing approaches could provide new opportunities to explore and expand the design envelope. Joining and Integration technologies, gaskets and sealants, as well as repair and refurbishment are also keys for Hypersonic applications.
To advance Additive Manufacturing (AM) technologies for production of rocket propulsion components the NASA Glenn Research Center (GRC) is applying state of the art characterization techniques to interrogate microstructure and mechanical properties of AM materials and components at various steps in their processing. The materials being investigated for upper stage rocket engines include titanium, copper, and nickel alloys. Additive manufacturing processes include laser powder bed, electron beam powder bed, and electron beam wire fed processes. Various post build thermal treatments, including Hot Isostatic Pressure (HIP), have been studied to understand their influence on microstructure, mechanical properties, and build density. Micro-computed tomography, electron microscopy, and mechanical testing in relevant temperature environments has been performed to develop relationships between build quality, microstructure, and mechanical performance at temperature. A summary of GRCs Additive Manufacturing roles and experimental findings will be presented.
To advance Additive Manufacturing (AM) technologies for production of rocket propulsion components the NASA Glenn Research Center (GRC) is applying state of the art characterization techniques to interrogate microstructure and mechanical properties of AM materials and components at various steps in their processing. The materials being investigated for upper stage rocket engines include titanium, copper, and nickel alloys. Additive manufacturing processes include laser powder bed, electron beam powder bed, and electron beam wire fed processes. Various post build thermal treatments, including Hot Isostatic Pressure (HIP), have been studied to understand their influence on microstructure, mechanical properties, and build density. Micro-computed tomography, electron microscopy, and mechanical testing in relevant temperature environments has been performed to develop relationships between build quality, microstructure, and mechanical performance at temperature. A summary of GRC's Additive Manufacturing roles and experimental findings will be presented.
Additive manufacturing methods for producing single materials are rapidly improving. The resulting material properties and microstructures are becoming more comparable to those of conventionally fabricated materials. However, the need for multi-functional and complex structures and components requires additional innovations in manufacturing such as multi-material and hybrid additive manufacturing approaches. Additive manufacturing machines with multiple print capabilities and combinations of AM, machining, and conventional processing methods will further open up design spaces and possibilities. In this presentation, several examples of the needs and methods for multi-material fabrication will be discussed with a focus on aerospace applications. Direct printing of silver coils in conjunction with fused deposition modeling, machined parts, and, binder jetting is being developed for innovative stator designs. Binder jetting of silicon-based materials with powder bed additions is being developed for heat exchanger applications. Additive manufacturing of bi-material systems is being pursued to fabricate lightweight, integrated, multifunctional structures.
Additive Manufacturing (AM) is being infused into aerospace industries at an accelerated pace. Reasons for this rapid adoption include: (1) Innovation Capability e.g. design features such as topology optimization, integrated fluid passages, and mesh structures; (2) Rapid Development and Optimization - ability to quickly iterate the design, development, and test cycle; (3) Affordability - reductions in part counts, cost, and schedule. NASA's Marshall Space Flight Center (MSFC) has taken a leadership role in application of AM technologies for deep space human exploration, leading the Agency's In Space Manufacturing (ISM) initiative and the application of AM for a broad variety of space propulsion systems. MSFC has championed the development of ISM capabilities since our first reduced-gravity aircraft experiment flew in 1999. Partnering with Made In Space, MSFC placed the first 3D Printer on ISS in 2014 and the second generation printer, the Additive Manufacturing Facility, in 2016. The next ISS technology demonstration will be the Refabricator, a recycler/basic printer scheduled to launch in late Fall 2018. Ground-based development is progressing in common use materials, metals 3D printing, printed electronics, and the new cornerstone of ISM, the FabLab. The latest developments in each area will be described. An overview of NASA's In Space Robotic Manufacturing and Assembly (IRMA) ground-based risk reduction projects will also be presented. MSFC has aggressively incorporated AM capabilities for design and development of space propulsion components. The capabilities have been rapidly matured and extensively exercised to produce and hot-fire test the Additive Manufacturing Demonstrator Engine, an in-space class prototype engine. This experience base has been extended to support Aerojet Rocketdyne in the application of AM to the RS-25, the Space Launch System Core Stage engine, and to small propulsion systems and thrusters for small satellites and cubesats. The latest developments will be described. In responding to a request from NASA's Commercial Crew Program for a consistent methodology for evaluation of AM processes and parts, MSFC began development of a draft standard for AM space flight hardware in late 2014. The draft was broadly disseminated for comments in mid-2015, and subsequently revised into two documents, a standard and a specification for AM space flight hardware, which were formally released by MSFC in October 2017. An overview of the key elements of these documents will be presented.
Additively manufactured (AM) injectors have the potential to improve upon the combustion performance achieved using traditionally manufactured (TM) injectors. Traditionally manufactured injector combustion performance decreases greatly in off-design conditions. Additively manufactured injectors hold the potential to sustain high combustion performance over a broader range of operating conditions than currently seen in TM injectors. Additively manufactured injectors promise to offer higher resistances to instability and achieve better overall propellant mixing and atomization for all types of combustion devices. This study expands upon previous studies that used 2-D imaging techniques to characterize the injector spray pattern of candidate AM injector elements. In this study, 3-D instantaneous measurements of the injector spray pattern are taken, allowing for deeper insight into the liquid spray breakup, an inherently 3-D phenomena. Stereo imaging is used for three dimensional analysis, which utilizes two cameras at different angles to reconstruct a three dimensional reconstruction. With this information, AM injectors can be designed to improve propellant mixing and atomization and reduce breakup length. As part of this work, a high-pressure, cold flow experimental spray facility was modified to measure each injector’s spray characteristics in terms of 𝑅𝑒 𝐿 and 𝑊𝑒 𝑔 . This facility is operated to capture instantaneous stereo photographic images, mass flow rates, and injector element thrust for pressure drop across the injector face ranging from 100 to 200 psig at a stiffness ratio of 1.0.
NASA's In Space Manufacturing Initiative (ISM) includes: The case for ISM - why; ISM path to exploration - results from the 3D Printing In Zero-G Technology Demonstration - ISM challenges; In space Robotic Manufacturing and Assembly (IRMA); Additive construction. Additively Manufacturing (AM) development for liquid rocket engine space flight hardware. MSFC standard and specification for additively manufactured space flight hardware. Summary.
In a NASA Aeronautics Research Institute (NARI) sponsored program entitled "A Fully Non-Metallic Gas Turbine Engine Enabled by Additive Manufacturing," evaluation of emerging materials and additive manufacturing technologies was carried out. These technologies may enable fully non-metallic gas turbine engines in the future. This paper highlights the results of engine system trade studies which were carried out to estimate reduction in engine emissions and fuel burn enabled due to advanced materials and manufacturing processes. A number of key engine components were identified in which advanced materials and additive manufacturing processes would provide the most significant benefits to engine operation. In addition, feasibility of using additive manufacturing technologies to fabricate gas turbine engine components from polymer and ceramic matrix composite were demonstrated. A wide variety of prototype components (inlet guide vanes (IGV), acoustic liners, engine access door, were additively manufactured using high temperature polymer materials. Ceramic matrix composite components included first stage nozzle segments and high pressure turbine nozzle segments for a cooled doublet vane. In addition, IGVs and acoustic liners were tested in simulated engine conditions in test rigs. The test results are reported and discussed in detail.
In a NASA Aeronautics Research Institute (NARI) sponsored program entitled "A Fully Non-Metallic Gas Turbine Engine Enabled by Additive Manufacturing", evaluation of emerging materials and additive manufacturing technologies was carried out. These technologies may enable fully non-metallic gas turbine engines in the future. This paper highlights the results of engine system trade studies which were carried out to estimate reduction in engine emissions and fuel burn enabled due to advanced materials and manufacturing processes. A number of key engine components were identified in which advanced materials and additive manufacturing processes would provide the most significant benefits to engine operation. In addition, feasibility of using additive manufacturing technologies to fabricate gas turbine engine components from polymer and ceramic matrix composite were demonstrated. A wide variety of prototype components (inlet guide vanes (IGV), acoustic liners, engine access door) were additively manufactured using high temperature polymer materials. Ceramic matrix composite components included first stage nozzle segments and high pressure turbine nozzle segments for a cooled doublet vane. In addition, IGVs and acoustic liners were tested in simulated engine conditions in test rigs. The test results are reported and discussed in detail.
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Systems and methods in accordance with embodiments of the invention implement additive manufacturing techniques that employ different sets of deposition characteristics and/or material formation characteristics during the additive manufacture of an object so as to strategically build up the object. In many embodiments, material used to build up an object is deposited at different deposition rates during the additive manufacture of the object, and the object is thereby strategically built up. In one embodiment, a method of additively manufacturing an object includes: depositing material onto a surface at a first deposition rate so as to define a first region of the object to be additively manufactured; and depositing material onto a surface at a second deposition rate so as to define a second region of the object to be additively manufactured; where the second deposition rate is different from the first deposition rate.
Metal additive manufacturing (AM) is a generic term that captures a variety of fabrication processes. Each of these manufacturing process has unique advantages and challenges for use in aerospace propulsion applications. The most commonly used AM processes include Powder Bed Fusion (PBF), Directed Energy Deposition (DED), and solid-state processes as in Cold Spray, Ultrasonic Additive Manufacturing, and Additive Friction Stir Deposition. While detailed research has been conducted among many of the AM processes to mature processing parameters and material properties, navigating which processes are best to select is difficult as it is based on specific component requirements. The focus of this presentation is to provide an overview of considerations for each of metal AM process selection for aerospace components based on various key attributes. These key attributes include geometric considerations, metallurgical characteristics, cost basis, post-processing and maturity of the processes. The data for these trade selections are based on studies that NASA as performed internally and with academic and industry partners. These studies include multiple AM build experiments to evaluate (1) geometric variations and constraints within the processes, (2) alloy characterization and mechanical testing, (3) pathfinder component development and hot-fire evaluations, and (4) certification approaches. This presentation summarizes these results and is meant to introduce specific examples which show what to consider when designing a metal AM component for aerospace propulsion applications.
This paper describes how the intent of current NASA fracture control requirements may be applied to “fracture critical” additively manufactured spacecraft hardware. Fracture control is a multi-discipline design and certification methodology that is applied in order to mitigate catastrophic failure of structures resulting from growth of an undetected crack-like defect. The methodology is defined in existing NASA standards and is required on all human-rated space structures. As legacy spacecraft structures have been built using primarily metallic and composite materials manufactured using well established methods, guidance for application of fracture control to parts composed of these material types has been established and is documented in several NASA requirements. Additive manufactured structures offer advantages in design flexibility and manufacturing efficiency and as a result are expected to continue to be used more and more in the future. Recently, relevant guidance has been published by NASA to define materials and processes requirements for certain additive manufactured hardware, but procedures for fracture control are not addressed yet in any requirements or guidance document. While use of additive manufactured parts in non-critical scenarios may be of relatively low concern in current structural certification processes, there is a need for new fracture control guidance in order to use and certify additively manufacture hardware that is “fracture critical” where failure of the part may result in loss of life or loss of vehicle. Assurance of damage tolerance, i.e., that as-built flaws in a given part either do not exist or will not grow to become catastrophic, is of particular interest to the fracture control community. This poses a challenge due to the fact that damage tolerance behavior is not well understood in additive manufactured parts compared to legacy material types and manufacturing techniques. The discussion contained herein is necessary at this time as new guidance in this area should be founded collaboratively by the technical community at large. Different hardware types (e.g., pressure vessel, structural member) are described to highlight specific challenges and solutions for each. The discussion concludes with considering specific disciplines within fracture control (non-destructive evaluation, materials & processes, fracture mechanics, and structural certification) in a proposed extension of existing fracture control requirements to additive manufactured parts.
This paper describes how the intent of current NASA fracture control requirements may be applied to “fracture critical” additively manufactured spacecraft hardware. Fracture control is a multi-discipline design and certification methodology that is applied in order to mitigate catastrophic failure of structures resulting from growth of an undetected crack-like defect. The methodology is defined in existing NASA standards and is required on all human-rated space structures. As legacy spacecraft structures have been built using primarily metallic and composite materials manufactured using well established methods, guidance for application of fracture control to parts composed of these material types has been established and is documented in several NASA requirements. Additive manufactured structures offer advantages in design flexibility and manufacturing efficiency and as a result are expected to continue to be used more and more in the future. Recently, relevant guidance has been published by NASA to define materials and processes requirements for certain additive manufactured hardware, but procedures for fracture control are not addressed yet in any requirements or guidance document. While use of additive manufactured parts in non-critical scenarios may be of relatively low concern in current structural certification processes, there is a need for new fracture control guidance in order to use and certify additively manufacture hardware that is “fracture critical” where failure of the part may result in loss of life or loss of vehicle. Assurance of damage tolerance, i.e., that as-built flaws in a given part either do not exist or will not grow to become catastrophic, is of particular interest to the fracture control community. This poses a challenge due to the fact that damage tolerance behavior is not well understood in additive manufactured parts compared to legacy material types and manufacturing techniques. The discussion contained herein is necessary at this time as new guidance in this area should be founded collaboratively by the technical community at large. Different hardware types (e.g., pressure vessel, structural member) are described to highlight specific challenges and solutions for each. The discussion concludes with considering specific disciplines within fracture control (non-destructive evaluation, materials & processes, fracture mechanics, and structural certification) in a proposed extension of existing fracture control requirements to additive manufactured parts.
Evaluation of Additively Manufactured Metals for Use in Oxygen Systems. Oxygen Compatibility: Additive Manufacturing (AM) is currently and will continue to be, used in oxygen systems; Compatibility studies are a necessity; Risks if not pursued - Equipment Damage, Loss of Mission, Loss of Life; NASA Centers of Excellence leading efforts -White Sands Test Facility (WSTF), Oxygen Compatibility Testing -Marshall Space Flight Center (MSFC), Additive Manufacturing -Glenn Research Center, Metals characterization -NASA Engineering Safety Center (NESC), Statistical Design of Experiments.