Additive Manufacturing, Arms Control and Delivery Vehicles: Challenges and Ways Forward

Nuclear arms control remains a priority for the foreseeable future for many stakeholders, and proposals have emerged to focus on capping nuclear warheads of the main nuclear-weapon states.

However, delivery vehicles are another source of instability and arms race dynamics. Whether they are coupled with weapons of mass destruction or considered exclusively in the context of their use with conventional weapons, missiles are increasingly transferred, produced, modernized, and used in military conflicts.

One important element in that increase is the development of technologies for advanced additive manufacturing. The importance of this technology has already been demonstrated in the civilian sector as Rocket Lab announced that parts of its Electron rocket would be produced through additive manufacturing (Winick 2019). In 2015, the weapon manufacturer Raytheon tested a design produced 80% through additive manufacturing (Raytheon News 2015). Using this technology could lower the cost of a missile program as well as, in the long term, the expertise required (Shaw 2017).

The development of offensive capabilities can also lead to a negative regional or global spiral with the increased deployment of defensive systems, and in response, new efforts to procure offensive weapons. It is therefore useful to keep thinking about ways to limit the destabilizing effect of these weapon systems. Some legal instruments currently exist in unilateral, bilateral or multilateral forums. Their focus may be limited to nonproliferation or they may cover a broader range of issues and address the behavior of states acquiring these delivery vehicles.

This article:

https://www.tandfonline.com/doi/pdf/10.1080/25751654.2022.2047360

will discuss ways in which these instruments can evolve to better respond to current trends and dynamics regarding missiles, but also will suggest new initiatives, particularly confidence-building measures, that could be useful to reduce the destabilizing effect of these systems.

AM para WMD: Qué si, y qué no

La fabricación aditiva (AM - Aditive Manufacturing) frecuentemente denominada con el término Impresión 3D, es una tecnología de fabricación relativamente novedosa, que se basa en la agregación de materiales capa sobre capa, de acuerdo con un modelo diseñado en 3D mediante un ordenador provisto del software adecuado.

Este novedoso método productivo contrasta en gran medida con el método convencional, basado en la retirada de material a partir de un bloque hasta lograr el diseño final, ya que permite obtener geometrías tan complicadas que serían imposibles de obtener si no fuera mediante fabricación aditiva. Además de esa ventaja, presenta otra ventaja no menos importante como es la reducción de residuos, ya que no se basa en la retirada de material que luego va a la basura.

Desde sus inicios en la década de los 80, la fabricación aditiva ha venido avanzado de manera lenta pero constante, si bien hay que dejar muy claro que es poco probable que reemplace a los métodos de fabricación tradicionales, cuando se trata de una producción a gran escala. Ahora bien: ¿Hasta qué punto puede ser utilizado este método para la fabricación de armas de destrucción masiva (WMD - Weapons of Mass Destruction)? Esta pregunta no es ociosa en modo alguno, pues ciertos informes de expertos en la materia han concluido que la combinación de fabricación aditiva y web oscura podría favorecer un aumento del riesgo de proliferación.

Ante esta posibilidad, la primera preocupación que se plantea es que pudiera permitir a entidades no estatales la producción de este tipo de armas, gracias a la sustracción de los pertinentes ficheros 3D. Afortunadamente para todos, hay que decir que esto no es tan simple de llevar a cabo por la sencilla razón de que los materiales esenciales no están disponibles ni son aptos para la impresión 3D. Quiero decir que no es posible producir un arma nuclear, química o biológica completa conectando un ordenador a una impresora 3D y presionando el botón de inicio.

¿Quiere esto decir que estamos entonces exentos de riesgo? No y sí: En el mejor de los casos, algunos componentes de las armas podrían imprimirse en 3D y otros componentes podrían adquirirse o producirse por otros medios. Pero aun así, es necesario contar con personas que aporten un imprescindible conocimiento y experiencia en el diseño y la producción de este tipo de armas, para unir todas las piezas hasta conseguir algo que sea verdaderamente utilizable. Por tanto, merece la pena no gastar más tiempo en esta hipótesis y centrarnos en cómo la fabricación aditiva puede ser una ayuda para que las entidades estatales puedan conseguir este tipo de armas de manera más eficiente.

Armas nucleares

Consideremos en primer lugar las armas nucleares. A este respecto, sólo puedo afirmar que hoy y ahora no conozco forma alguna de imprimir con seguridad núcleos de material fisionable. Como mucho, podría ser utilizada para la fabricación de piezas con destino a centrifugadoras. Pero el núcleo fisionable, no. Hoy y ahora desde luego no.

Armas químicas

En términos de armas químicas, hoy y ahora existen ciertas tecnologías de manufactura aditiva que podrían ser utilizadas para obtener microrreactores con los que sintetizar productos químicos a muy pequeña escala, de una manera segura y eficiente. Desde luego no todos los compuestos utilizados para la fabricación de armas químicas podrían obtenerse mediante esos microrreactores, pero otros productos químicos peligrosos podrían ser obtenidos. Esto plantea un riesgo de proliferación moderado en algunas aplicaciones de armas químicas.

Armas biológicas

En el campo de las armas biológicas, la manufactura aditiva puede ser utilizada hasta cierto punto para la producción de armas biológicas, al menos como posibilidad técnica a futuro, ya que podrían utilizarse bioimpresoras para cultivar agentes biológicos. ¿Cuál es el problema hoy y ahora? Pues que las impresoras para materiales biológicos actualmente son muy caras, requieren un gran conocimiento y experiencia, y no son en modo alguno tan accesibles como el resto de impresoras.

Misiles

El área relevante para las armas de destrucción masiva que puede verse más favorecida a corto plazo por la manufactura aditiva es el de los vehículos de transporte; más concretamente, misiles. En este sentido, la manufactura aditiva ya se utiliza ampliamente en las cadenas de suministro relacionadas con la industria aeroespacial, para imprimir componentes de misiles y cohetes. ¿Qué componentes? Fundamentalmente, componentes de motores: El problema de los motores o al menos uno de sus problemas, es que cuantos más componentes forman el motor, más puntos de ruptura añadimos al motor. Sin embargo, la manufactura aditiva permite diseñar y fabricar conjuntos de una sola pieza, eliminando así -o al menos disminuyendo- los puntos de ruptura. Además, al simplificar el conjunto disminuye en gran medida el peso del motor, lo cual supone tambien un cierto ahorro de combustible y un mayor alcance, por no hablar del recorte de costes y tiempos en el proceso de fabricación. 

A new approach to eliminating enclosed voids in topology optimization for additive manufacturing

Topology optimization is increasingly used in lightweight designs for Additive Manufacturing (AM).

However, conventional optimization techniques do not fully consider manufacturing constraints.

One important requirement of powder-based AM processes is that enclosed voids in the designs must be avoided in order to remove and reuse the unmelted powder.

In this work, Drs. Yulin Xiong, Song Yao, Zi-Long Zhao and Yi Min Xi propose a new approach to realizing the structural connectivity control based on the bi-directional evolutionary structural optimization technique.

This approach eliminates enclosed voids by selectively generating tunnels that connect the voids with the structural boundary during the optimization process. The developed methodology is capable of producing highly efficient structural designs which have no enclosed voids.

Furthermore, by changing the radius and the number of tunnels, competitive and diverse designs can be achieved. The effectiveness of the approach is demonstrated by two examples of three-dimensional structures. Prototypes of the obtained designs without enclosed voids have been fabricated using AM.

Read more:

https://www.sciencedirect.com/science/article/pii/S2214860419315519?via%3Dihub

RAPID + TCT: Additive Manufacturing with Refractory Metals for Hypersonic Missiles

Refractory alloys have extraordinary resistance to heat and wear. With superior durability, are often the desired material for extreme environment applications such as space craft, missiles, and hypersonic vehicles. Due to the difficulty and high cost associated with manufacturing in complex shape, their utilization has been hampered even in the most demanding applications.

Additive Manufacturing, 3D printing, on the other hands has demonstrated a superior shape producing capability that is unattainable with traditional manufacturing processes. Develop and mature 3D printing of refractory metal alloys would greatly enhance the extreme environment product’s performance and lowering the cost.

In the NASA and private industry collaborative research and development work, to be presented at RAPID+TCT, successful 3D printing of high-quality Niobium C103 alloy components have been demonstrated and hot fire tested.

The properties of 3D-printed Nb C103 were compared to its equivalent wrought product, including the effect of heat treatments on microstructure evolution and materials properties. The 3D “as-printed” microstructures were extremely stable and largely intact even after 2 hours at 2900°F which is often exceeded this material’s application demand.

Superior properties of 3D-printed Nb C103 were observed from room temperature to elevated temperature. Hypothesis for such stable microstructures is proposed and validated. This work demonstrated a robust 3D printing process with superior materials properties, significant leap in producing highly sophisticated geometries, and sufficiently lowered manufacturing cost. A case study of performance gain in sophisticated Nb C103 engineered hardware will also be presented at RAPID+TCT.

More info:

https://rapid3devent.com/sessions/3d-printing-refractory-metals-for-extreme-environment-applications/

Additive Manufacturing to modernize the US Military

“Innovation” and “force modernization” are the Pentagon buzzwords of the day: Strategies are being developed across the Department of Defense enterprise, with these concepts as the foundational pillars. But oddly enough considering the defense budget of the United States compared to the defense budget of Russia or China, for the first time in decades the United States military apparatus does not possess a clear advantage on the world stage.

¿Causes? The flattening of the technological landscape and emergence of strongly modernized adversaries like Russia and China. Both causes requires that the U.S. innovate to remain dominant not only in technological progress but also in the ability to field systems more rapidly than their peer adversaries.

¿Solutions? Of course, there are not magical solutions, but the undersecretary for research and engineering, Michael Griffin, and other DoD leaders, believe that, in many ways, the Additive Manufacturing could boost the solution. They emphasize this approach in the fiscal 2019 budget request: $90 billion in R&D with increases concentrated in rapid prototyping for testing activities.

For the Pentagon, the Additive Manufacturing can serve as a foundational tool to accelerate new weapons development and provide innovative solutions to win the wars of the XXI Century. Bearing this in mind, industry partners, military operators, and members of the science and technology communities should certainly take notice: DoD leaders are increasingly placing their bets on Additive Manufacturing and they are thinking on using it not only for rapid prototyping in the early stages of development, but also for manufacturing of end-use parts.

Internet of nuclear things: Managing the proliferation risks of 3-D printing technology

Over the next decade, the spread and maturation of Additive Manufacturing could challenge major control mechanisms for inhibiting nuclear proliferation.

At the same time, the cyber-physical nature of this production technology creates the potential for the emergence of an Internet of Nuclear Things, which could be harnessed to increase the information visibility of dual-use activities in civil nuclear programs.

This new capability could offer unique opportunities to mitigate proliferation risks and augment traditional methods of regulating and monitoring sensitive nuclear technologies. But barriers stand in the way of leveraging an Internet of Nuclear Things –notably, political issues related to information access and integrity.

As additive manufacturing technology matures, government and industry stakeholders should adopt a strategic approach toward an evolving Internet of Nuclear Things – an approach that would include principles to encourage transparency within the Internet of Nuclear Things and ensure the integrity of the information it produces.

Read more:

https://www.tandfonline.com/doi/abs/10.1080/00963402.2018.1436811?journalCode=rbul20

Missile Defense: ¿Why should an army wait a year to get end-use parts that It could be 3D-Printed?

Defense companies are using Additive Manufacturing more often today to build parts for weapons: Aerojet Rocketdyne is using the technology to build rocket engines, Huntington Ingalls is using it to build warships and Boeing is 3D printing parts for its commercial, defense, and space products. “In particular, rapid prototyping, along with the creation of highly specific and technical parts are orders of magnitude faster and cheaper than traditional manufacturing methods,” said a recently released RAND report. 

Someday, the military will 3D-print missiles as needed, the U.S. Air Force’s acquisition chief says. In the shorter term, he just wants to use Additive Manufacturing Technology to get broken planes back in the air. The roadblock is legal, not technical: “I have airplanes right now that are waiting on parts that are taking a year and a half to deliver. A year and a half,” Will Roper, the assistant Air Force secretary for acquisition, technology and logistics, said in an interview.

The Air Force is already 3D-printing niche projects whose original suppliers no longer exist. The problem is with parts whose manufacturers are still around, but which no longer make the specific item in need. Today’s 3D-printers could make short work of those deliveries, but some of those parts’ original manufacturers control the intellectual property —and so far, the service lacks clear policy for dealing with that: “The reason I can’t say we’re going to do it is we’re talking about government contracts and IP, so I have lawyers that are helping me and other contracts folks,” Roper said. “But it’s an area I’m going to stay focused because I see a way for win-win. And that doesn’t happen often in the government.”

Missile building related companies firms up investments in Additive Manufacturing and other technologies

Missile building related companies keep investing in new types of manufacturing. Let us summarize some of those investments:

Aerojet Rocketdyne is using Additive Manufacturing to make rocket engines.

Boeing has invested in Digital Alloys, a company that is developing high-speed, multi-metal Additive Manufacturing systems to produce 3D-printed parts for aerospace and other production applications.

Raytheon has opened a $72 million, 30,000-square-foot (2,787-square-meters) facility that houses automation technology to support complex radar testing and integration.

HorizonX has invested in Morf3D, a company whose technology enables light and strong 3D-printed parts for aerospace applications.

Lockheed Martin is using Additive Manufacturing in its Gateway Center.

Application of Additive Manufacturing Technologies in Missile Manufacturing Industry: Strategy of India

Additive Manufacturing (AM), also popularly known as 3D Printing, is revolutionising the missile manufacturing landscape and presents huge challenges for a country’s defence capability and security.

(Read more)

Large Format Additive Manufacturing to make end use parts for the USAF

A former grocery store in middle Georgia is now serving as Air Force Advanced Technology and Training Center.

The center employs now about 30 people and may eventually employ about 100. This lab is the second one like it in the Air Force. The first one is connected with Wright-Patterson Air Force Base in Dayton, Ohio.

The facility is a satellite operation of Robins Air Force Base. It officially opened Oct. 24, and involves 3D Printing, also called Additive Manufacturing, as a key technology. Previously, 3D Printing had been thought of primarily as something to make prototypes, but now the Air Force is looking at using it to make end use parts.

The inside of the brick building —a former Publix store in Warner Robins— is full of gleaming new futuristic machinery, with large and very large format 3D Printers and 3D Scanners as starrings: In words of Maj. Ben Steffens, “Much of the work that has been done on the base has been done in the same method for years and years. This equipment, this technology, this material that we are dealing with here is cutting edge and will bring us to the next level as far as keeping our schedule down, keeping our cost low.”

Northrop Grumman: Additive Manufacturing for its new LEO Warhead for Hypersonic Missiles

In late March this year at the EMPI Test Facility in Burnet, Texas, Northrop Grumman, using Internal Research and Development (IRAD) funding, demonstrated its new LEO warhead for the first time to customers competing for the DoD hypersonic weapons contracts. This new warhead development marked the first time that the company had made some of its specific warhead components -including the fragmenting inner body- using Additive Manufacturing (AM).

This 50 lb-class warhead has been designed to equip future US air-to-surface and surface-to-surface hypersonic weapons to defeat a broader range of target sets, from ground forces to light/medium vehicles and aircraft.  The new warhead leverages the company's Lethality Enhanced Ordnance (LEO) technology: a scalable fragmentation/penetration warhead solution developed by Northrop Grumman in response to a US Department of Defense (DoD) requirement that by 2019 cluster munitions containing submunitions do not result in more than 1% Unexploded Ordnance (UXO) after arming. Unlike submunitions, LEO technology uses a thinned out shell casing supplemented with an inner fragmentation layer that can be scaled according to the required target set. Northrop Grumman said that in a series of warhead tests with LEO technology achieved the army's stated requirements for area effectiveness, and left behind no UXO.

Masten Space Systems Selected for NASA SBIR Phase 1 Award

Masten Space Systems of Mojave will pursue a project designed to better use Additive Manufacturing (AM) in the production of rocket engines with the help of NASA funding.

(Read more)

AM-fueled missile proliferation: ¿How to address this threat?

Current exports-control regulations are not prepared to stop Additive Manufacturing (AM) from fueling arms proliferation in the near future: Their spectrum only captures a fraction of the critical equipment and digital data needed to manufacture arms with an AM console, because dual use goods, which they are, generally escape stricter export-controls. 

AM allows creating complex single-pieced shapes that cannot be achieved with subtractive methods, thus limiting the number of needed fixations and with it, the risk of failure. But their most critical feature in this case is that most AM technologies require only a digital model of the desired object, a “build-file” in the form of electronic data, in order to manufacture it almost instantly.

This means that, in theory, the owner of an AM console can manufacture virtually any object, including weapons and other “products that are subject to dual-use and arms exports control”, provided he owns the necessary build-files. And the problem is these build-files are of course extremely easy to transfer by electronic means, like e-mail or FTP for example. This is why AM poses such a challenge to existing exports-control regimes, because it has the potential to enable export control circumvention and contribute to illicit weapon programs.

Initiatives are definitely building up and SIPRI (Stockholm International Peace Research Institute) researchers strongly suggest to start by amending export control regimes so that they can include AM consoles and the equipment they require, especially laser beams and feedstock materials. Pointing out some obvious flaws in existing exports-control regimes, the SIPRI researchers find that when it comes to controlling transfers of missile production equipment, for example, the international Missile Technology Control Regime (MTCR) only limits sales of equipment whose exclusive function is to produce missile systems. Dual-use equipment, such as AM consoles, do not fall under this regulation. Identical issues also affect the transfer of the raw-materials used by the machines. However, the researchers also notice that the overall literature surrounding export controls is progressively opening to the inclusion of dual-use goods in their spectrum to address AM-fueled missile proliferation.

Orbital ATK, ready to provide the GBSD program

As designs for the next generation ICBM are being matured, Orbital ATK’s experience has resulted in smart commonality, commercial practices, and shared facilities and workforce.

The company has honed numerous capabilities that can reduce risk and shorten development timelines for GBSD. As an experienced flight system/launch vehicle provider, the company has integrated and launched flight systems at sites around the world, and advanced, common avionics have flown on more than 100 missions with 100 percent success.

Including strategic missile targets and interceptors, Orbital ATK has developed, on average, two new flight systems each year for the past 20 years. In addition, Orbital ATK has significant experience building flight-proven composite structures like shrouds, interstages and motor cases. The company has also developed nuclear hardness and survivability protection for its structures, which will help ensure the success of GBSD.

Orbital ATK has modern, automated facilities ready to support GBSD development and production. The company currently utilizes Additive Manufacturing, virtual reality and model-based systems engineering to design and build state-of-the-art rocket motors. In 2017, Orbital ATK’s solid rocket motors achieved 100-percent success on 16 flights and 11 static fires for a total of 64 motors fired.

Orbital ATK has played a key role on every Intercontinental Ballistic Missile (ICBM) program for more than five decades. Since the Minuteman I was first fielded in 1962, Orbital ATK, along with its legacy companies, has provided motor stages and refurbishment services for the program. Today, Minuteman III continues to play an integral role in our nation’s defense, but is preparing to be replaced by the next generation ICBM program: Ground Based Strategic Deterrent (GBSD).

The Minuteman III weapon system is projected to be in service through 2030, and sustainment activities like those Orbital ATK is now performing on a Propulsion Subsystem Support Contract for the U.S. Air Force Nuclear Weapons Center, Intercontinental Ballistic Missile Systems Directorate at Hill Air Force Base, will ensure operational readiness through that time. Once Minuteman III is retired, the Air Force’s GBSD program will take over: “The Orbital ATK team is dedicated to helping the Air Force with a smooth transition to the GBSD system,” said Charlie Precourt, Vice President and General Manager of Orbital ATK’s Propulsion Systems Division. “Minuteman III sustainment is a vital element of our nation’s defense and the Air Force is partnered with Orbital ATK to ensure that Minuteman remains safe, capable, reliable and responsive while beginning development of GBSD."

With a long history of ICBM experience, proven expertise in flight systems and components, and the ability to share facilities and experienced workforce across programs to keep costs down, Orbital ATK is ready to provide the GBSD program with outstanding solutions throughout its lifecycle.

Spain: 3D printing and AI to allow rockets evolve like nature

FADA-CATEC (Fundación Andaluza para el Desarrollo Aeroespacial - Centro Avanzado de TECnologías) is supporting Zero 2 Infinity (Z2I) in the development of a new generation of rocket engines.

Recently, FADA-CATEC has successfully 3D printed a combustion chamber for Zero 2 Infinity's Bloostar engine. Jose Mariano López-Urdiales, founder and CEO of Zero 2 Infinity, praised the benefits of 3D printing: "Traditional rockets have had straight cooling channels because that's all that could be manufactured. When you put a flashlight in your ear, you see a wonderful tree-like structure of blood vessels. We don't have straight rows of blood vessels in our ears. 3D printing and AI now allow rockets to evolve, like nature."

Zero 2 Infinity is an spanish privately-owned company with subsidiaries in Germany and the United States. The plans of the company include using AI (Artificial Intelligence) and neural networks to optimize the cooling of the thrust chamber via structures that cannot be manufactured by any other means.

Additive manufacturing to develop advanced warheads

In words of Richard Truitt -Orbital ATK’s program manager for warhead development programs- “Additive Manufacturing allows us to make complicated geometries, which would benefit a hypersonics application, without the nasty, long schedule,” .

And beyond building warheads rapidly for testing, manufacturing them using 3D Printing capabilities would likely drive down the cost because instead of a machinist starting with a solid chunk of steel or aluminum, which is expensive, and throwing away 99 percent of it, there is no waste. “It’s an enabling technology for us to design and deliver weapons or warheads and get them to the warfighter,” Truitt said.

In what is a major first for the company, Orbital ATK announced the successful test of a partially-3D printed warhead designed for hypersonic weapons. Taking place on March 29, the testing comes just sixty days after conception, with three out of five of the warhead’s major components made using Additive Manufacturing. Speaking to Defense News, Orbital said the test aimed to examine what effects the fragmentation will have on various targets.

Orbital ATK’s efforts are among many initiatives both within U.S. industry and the Defense Department to stay ahead of peer competitors Russia and China, who are both heavily engaged in developing hypersonic weapons. Orbital decided to try Additive Manufacturing on a warhead design for hypersonic applications because the Defense Department is moving full speed ahead with hypersonic technology development in the coming years as it decides how it will employ such weapons.

The company has developed its LEO (Lethality Enhanced Ordnance) warhead capability and some modeling techniques to help look at fragmentation design on certain target sets. In words of Pat Nolan -vice president and general manager of Orbital ATK’s missile products division- “Now we’re coupling our rocket motor hypersonic experience with our warhead design experience to design a warhead that can survive at high speeds, high temperatures, when you’re going that fast,”. The company wants to be ready with the right modeling when hypersonic weapons prototypes and testing begin to ramp up, and the data obtained in the test will be used to measure up against what the engineers believed would happen based on modeling and simulation. The test itself was conducted in a traditional arena where the warhead is hung from above and metal panels surround it in a half circle that are designed to measure how the fragmentation from the warhead disperses upon detonation. High-speed cameras are rigged to measure the velocity of the fragmentation. Another two panels that consist of layers of material -in this case housing insulation- are designed to capture shrapnel in order for the pieces to be measured as well as the depth of perforation.

The 50 lb (22 Kg) warhead went from conception to test in 60 days, according to Truitt. The team began designing the warhead at the start of February, he said, and using Additive Manufacturing to build a large portion of the components cut out at least a month and a half to manufacture the warhead. “If you walk around it, you will see it’s not a cylinder, it’s got some really complicated dimensions. Getting that part in that dimension in a very short time is nearly impossible,” Truitt said. Orbital received the hardware to build the warhead in less than two weeks, he added. “We are really happy to do this test with additive manufactured parts because it is going to tell us, does that actually function the way a normal component would,” Truitt said prior to the test. 

Additive Manufacturing to develop "All-in-One" Injector Heads

In a propulsion module, tremendous forces develop under extreme conditions. This demands maximum levels of reliability and precision in a small space. The injection head is one of the core elements of the propulsion module, feeding the fuel mixture into the combustion chamber. Its traditional design consists of 248 components, produced and assembled in various manufacturing steps.

The different processing steps, such as casting, brazing, welding, and drilling, result in weak points that can constitute a risk under extreme loads. Moreover, it is a time-consuming and complex process: In the field of injector elements, conventional production requires over 8.000 cross holes to be drilled in copper sleeves that are then precisely screwed to the 122 injector elements in order to mix the hydrogen that streams through them with oxygen.

A glance at these figures clearly shows that, from the perspective of risk one functionally integrated component combining all the elements is an obvious but ambitious goal. This could also release huge economic potential and cut the number of processing steps as well as production time, especially for a Class 1 component. Missions costing hundreds of millions depend on these components. Accordingly, engineers are constantly seeking to develop components of the highest quality, functionality, and robustness while simplifying the manufacturing chain and reducing the number of individual elements.

Thanks to Additive Manufacturing, Ariane Group has succeeded in taking this to a whole new level: The injector head of a rocket engine has been simplified and reduced to what is literally an AiO (All-in-One) design. The results of the new injector head produced using additive manufacturing are extremely impressive: Instead of 248 parts, it consists of just one -with the same functionality- and cutting the required time down to a minimum. The project team chose a heat- and corrosion-resistant nickel-based alloy (IN718) as the material to print the 122 injection nozzles, the base and front plates, and the distribution dome with the corresponding feed pipes for the hydrogen and oxygen fuels as one integrated component. In words of Dr.-Ing. Steffen Beyer, Head of Production Technology – Materials & Processes at Ariane Group, “Only additive manufacturing can combine integrated functionality, lightweight construction, a simpler design, and shorter lead times in a single component.” 

Additive Manufacturing to develop advanced fuel systems

According to Jeff Engel, COO of Reaction Systems Inc., "in hypersonic flight the combustor temperature gets so high that materials can’t survive in that environment; you have to continually cool the combustor sections."

Reaction Systems is developing a fuel system to absorb that heat load from the combustor specifically, so that the final speed of the vehicle is faster. But transferring the heat to the working fluid, while providing a maximum surface area for catalysis inside the heat exchanger, is essentially impossible to achieve with conventional heat exchanger fabrication technologies.

Additive Manufacturing from Faustson Tool Corporation is enabling the heat exchange technology: Faustson’s Concept Laser M2 cusing Multilaser can build with a variety of high-performance alloys, including cobalt-chromium grades, Ti6Al4V, pure titanium and the material for Reaction Systems’ heat exchanger, Inconel 718.

Ceramic Additive Manufacturing to develope future Hypersonic Missiles

Additive manufacturing of ceramic materials might be the key to develop future hypersonic missiles.

Ceramic materials such as Silicon OxyCarbide (SiOC) can withstand incredible temperatures.

If shaped into complex geometries, the SiOC material could be exactly what engineers are looking for: “If a material can withstand those temperatures – roughly 3,200 degrees Fahrenheit [1.760 degrees Celsius] – it could be used for hypersonic aircraft engine components like struts or flame holders,” Jamie Szmodis, a hypersonic research engineer with the Air Force Research Laboratory’s Aerospace Systems Directorate, said.

But that is only if materials like SiOC can be shaped into the complex structures needed for hypersonic flight where heat stresses are extreme. To harness the potential of the material, the Air Force is partnering with private laboratories that are pioneering novel manufacturing processes. The Air Force recently signed a Cooperative Research and Development – Material Transfer Agreement with HRL Laboratories to test its novel manufacturing processes: “The potential of the HRL-produced materials for demanding Air Force applications became apparent while Aerospace Systems Directorate scientists were searching for new thermocouple radiation shields,” reads a release from the Air Force Research Laboratory. “The SiOC materials were produced through an additive manufacturing process utilizing a pre-ceramic resin. Following part fabrication, the pre-ceramic resin was heat treated to convert the component to a fully ceramic state. AFRL scientists became interested in HRL’s novel process taking advantage of state-of-the-art 3D printing capabilities and pre-ceramic resin chemistry as well as the possible performance of the final SiOC materials at high temperatures.”

The agreement is also beneficial to HRL Laboratories, which can receive early feedback from what is likely to be its largest customer. “The extreme temperature testing that AFRL performed revealed the limits of our new material and challenged us to improve it,” Dr. Tobias Schaedler, a senior scientist from HRL, said. If the Air Force and HRL Laboratory’s collaboration pays off, they could potentially solve the biggest outstanding challenge with developing hypersonic air vehicles, which is essentially material sciences. Right now, there are no materials that can withstand the extreme heat and stress generated during hypersonic flight. 3D printed ceramics might just be the solution to that problem. Time, of course, will tell. The partnership agreement is beneficial for the Air Force because it is not just a customer but, rather, the service participates in the development process, gaining valuable expertise: “Without the material transfer agreement, we would have purchased the samples to test them. We would have been a customer, as opposed to a collaborator,” Szmodis said. “With the agreement we are able to provide test results to HRL and provide feedback that is valuable to both parties.”

Aerojet Rocketdyne bets for the Additive Manufacturing

Aerojet Rocketdyne has invested time and resources over the last two decades to evolve Additive Manufacturing technology to meet the stringent requirements of rocket engine and defense systems applications.

In recent years, Aerojet Rocketdyne has notched several successes in developing this technology for a broad range of products, from discrete component demonstrations to hot-fire testing of engines and propulsion systems made entirely with Additive Manufacturing.

Aerojet Rocketdyne has also been working to differentiate its Defense Advanced Programs (aka Rocket Shop) using the new design spaces enabled by Additive Manufacturing. Rocket Shop examples include tactical (hypersonics), missile defense and strategic systems applications.

Benefits

Cost: The use of Additive Manufacturing dramatically reduces the amount of touch labor required to build many engine components, which allows them to deliver more affordable legacy products and new product applications to their customers. 

Schedule: Components that once took hundreds of hours to produce with traditional manufacturing techniques can now be built in just days using a single machine. This reduces lead times significantly and allows them to bring their products to market more quickly.

Flexibility: Aerojet Rocketdyne’s engineering team has refined its approach to the design process to reflect the dramatically expanded possibilities enabled by Additive Manufacturing. They are free to design products that were once thought impossible due to the constraints of traditional manufacturing.

What Sets Them Apart

Powders: They fully understand powder feedstock that is utilized – including particle size, distribution and chemistry – to make sure the resulting alloys can perform under the extreme pressures and operating conditions of rocket engines.

Process: They have worked directly with OEMs to learn the intricate details about how the selective laser melting process works so they can adjust parameters -- such as laser speed, and core and contour scan strategies -- to achieve optimal microstructures and surface finish features to meet their requirements.

Properties: They have performed detailed analysis of components built using Additive Manufacturing to fully characterize the materials and properties to make sure they will perform as designed. They actually test the alloys at the extreme operating conditions faced by their products, including temperatures that range from -320°F to 2,100°F (-195ºC to 1.148ºC). They account for all those operating environments in their designs to ensure they can operate in the extreme environments of space.