Metal Additive Manufacturing and the New Space Race: the Inside Track with Launcher and AMCM

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LAUNCHER & THE NEW SPACE RACE FALCONTECH’S SUPER AM FACTORY AUTOMATION IN METAL AM

Metal Additive Manufacturing and the new Space Race: The inside track with Launcher and AMCM

In October 2020, New York City-based space technology company Launcher started testing its full-sized E-2 liquid rocket engine, designed to deliver the highest performance at the lowest cost for smaller space launch vehicles. That the E-2 features a one metre tall single-piece copper alloy Laser Beam Powder Bed Fusion (PBF-LB) combustion chamber is remarkable. What is even more impressive is the fact that Launcher, a company with less than twenty employees, achieved this in a short time frame and to a relatively modest budget. Metal AM magazine’s Nick Williams reports on the project and Launcher’s close collaboration with specialist PBF-LB machine builder AMCM GmbH.

The first Space Race defined The reason for metal AM’s cost on all but the largest rocket technological progress and human success? It offers the ability to develop engines. So, what was once only ambition in the mid-20th century, and manufacture rocket engines affordable and accessible to super- with the launch of Sputnik 1, the at a fraction of the cost of past powers is now being chased by a new first artificial satellite, and the technologies, dramatically speeding generation of private space firms. landing of the first humans on the up development times and leveraging One such entrant in this new moon with the Apollo 11 mission. efficiency gains – particularly in terms Space Race is Launcher, a small, but, The first two decades of the 21st of combustion efficiency – that would judging by the talent and experience century, however, have already previously have been at prohibitive it has attracted, credible rocket seen radical changes in the space sector. Today, it is private companies which are at the forefront of a new, commercially-driven Space Race, competing in large part to capture a share of the booming demand for orbital launch vehicles for private and state-owned satellite deliveries. Whilst SpaceX is now a house- hold name with a gravitational pull to rival that of NASA’s at the height of the Space Shuttle programme, there are many other companies, large and small, which also have ambitions in this field. What connects all of these privately- owned firms, as well as national and regional state-backed agencies, is the recognition that metal Additive Fig. 1 Launcher believes that its E-2 engine, here on the test stand at NASA’s Manufacturing is one of a small Stennis Space Center in October 2020, will be the highest-performance, number of technological innovations lowest-cost liquid rocket engine for smaller space launch vehicles (Courtesy enabling this revolution. Launcher/John Kraus)

Fig. 2 Members of the Launcher team preparing for the E-2 test fire. Left to right: Andre Ivankovic, Max Haot, Igor Nikishchenko, Ivy Christensen, Viktoria Skachko, Rich Petras and Luis Rodriguez (Courtesy Launcher/John Kraus)

development company based in New systems. As well as interviews “While there are many other York, USA. Founded by CEO Max with Haot, insight is shared by hopeful companies around the Haot, an experienced entrepreneur Launcher’s Chief Designer, Igor world trying to develop orbital whose successes include the internet Nikishchenko, and AMCM’s launch vehicles, it is clear to us streaming company Livestream, the Christian Waizenegger. that only a small percentage will team at Launcher has made rapid succeed. This is true of many indus- progress over the last two years in tries, and reflects, for example, designing and testing what it believes The bigger picture of the the early days of the internet. This will be the highest-performance, new Space Race new Space Race is enabled by the lowest-cost liquid rocket engine for lowering cost of entry to reach smaller space launch vehicles. So Explaining the current status of orbit – something that has been far, Launcher has raised $6 million, a the private space business and its achieved through innovations such relatively modest sum for this sector drivers, Haot told Metal AM maga- as metal Additive Manufacturing, and the level of the company’s ambi- zine, “Only eleven countries have new electronics, software, etc, tions, which includes private funding the technology to deliver satellites combined with a demand for as well as a $1.5 million Air Force to orbit using their own rockets. smaller rockets, which are in turn Small Business Innovation Research For a long time, only one private cheaper to develop. While many grant to accelerate development of company succeeded in reaching countries would not, in the past, its E-2 engine. orbit – SpaceX – followed more have attempted a space programme This article tells the story of recently by a second company, due to its high cost, these new lower Launcher’s journey to the point Rocket Lab. There’s also a third barriers to entry are stimulating that it has reached today, the one in China. All companies that most countries to seek the develop- development of its E-1 and E-2 have reached orbit have valuations ment of a domestic small launch engines, its collaboration with AM well in excess of $1 billion and, vehicle capability – perhaps in part machine builder AMCM GmbH, and as a result of their success, have for prestige, but also to be able to the wider picture of the commercial access to the capital needed to independently send their own small opportunities in space delivery grow their products and services.” satellites to orbit.”

Haot believes that the winning formula for small launchers is to focus on the highest performance at the lowest cost – even if it takes a little longer than the competition. “High-performance engines can help us double or triple the payload when compared to a lower-performing rocket of the same size. This is a significant commercial advantage to reduce prices or grow margins.” Explaining just how important efficiency is when it comes to rocket systems for commercial space deliveries, Haot stated, “Since more than 90% of a launch vehicle’s mass is propellant, reducing propellant use is the biggest opportunity to reduce vehicle mass and, as a result, increase payload. Payload represents just 1–3% of the vehicle mass, so, by increasing performance, you can double or triple your payload for the same rocket size.” Crucial to both Launcher’s business model and the technological challenges it faces is metal Additive Fig. 3 A digital render of the E-2 engine on the Launcher Light launch vehicle Manufacturing. “AM is a key enabler. for small satellites (Courtesy Launcher) Launcher could not be testing full-scale, highest-performance combustion chambers with the funding we have raised if AM part SpaceX’s Starlink system. “We innovation, competition, and new was not available. The traditional all use satellite infrastructure every applications. This is the shift in technologies used to manufacture day without thinking about it; when this historically stagnant industry combustion chambers, machining we fly, drive, check the weather or and it is happening now, and and vacuum brazing, would be out of use the GPS-enabled navigation in accelerating.” reach for us,” explained Haot. “Since our phones, satellites are playing a key role. Beyond this, imaging and day one, our goal has been to have A mutually beneficial our first test flight in 2024 and to earth observation, earth sciences, relationship with state reach orbit and be profitable in 2026. high-speed communications, and We hope to reach this objective with defence are all enabled by satellites. agencies less than $50 million invested, which As well as the race enabled by would be a record and breakthrough smaller conventional satellites, new Despite this revolution in the struc- for the industry and for Launcher.” types of low Earth orbiting satellite ture of the space industry, a close constellations such as Starlink relationship between established deliver high speed internet to rural national and international space The satellite business locations. As a result, there is a agencies and the new commercial demand to launch more than 30,000 players is both vital and mutually The commercial motivations and new satellites in the next five years beneficial, explained Haot. “The opportunities driving the private alone.” United States Air Force, and now space businesses primarily exist Whilst a satellite used to cost the US Space Force, are the biggest around the booming satellite a few hundred million dollars to buyers and users of satellite launch business. Since Sputnik 1 in 1957, design, build, and launch, now it can capabilities in the USA. In addition, around 5,000 satellites have been be done for a few hundred thousand their mission is to have access to sent to orbit, although only about dollars. “This changes everything,” the best technology in the world. 2,000 are operational. In the last stated Haot, “and entrepreneurs Therefore, investing in R&D and 18 months alone more than 500 and venture capitalists can, at last, innovation has been the DNA of the satellites have been sent to orbit as be involved in this industry to bring Air Force since its inception.”

combined with what Haot believes will be an expected design lifetime of at least fifteen years, including iterative improvements, means that the rewards for success will be high. When the team at Launcher specified the E-2 engine and defined its roadmap back in 2017, it initially set the development of the turbopump as its first goal. Laser Beam Powder Bed Fusion (PBF-LB) machines were already available with the necessary build volumes for this application but at the time, explained Haot, no machine was available with the required one metre build height to create the E-2 combustion chamber in one part, and the company estimated that one was unlikely to be available before 2020. “Our competitors chose to print their chambers using existing machines, either by producing smaller engines or producing chambers consisting of three parts or more. This approach, however, reduces combustion/ Fig. 4 A cutaway view of an E-1 thrust chamber prototype showing the types of cooling performance and increases complex internal cooling channels that can be created by Additive Manufac- engine weight, as well as increasing turing (Courtesy Launcher/ 3T-AM) costs.” “We had been pushing for a larger AM machine with a number “As part of its plan to have more The story of the Launcher of PBF-LB system developers, but launch options to buy from, and E-2 engine at the time only Germany’s AMCM, more competition and innovation part of the EOS Group, was ready to – especially in responsive small At the centre of Launcher’s roadmap take a chance on this format and to launch vehicles – the Air Force has is its ambitious plan to develop the align their development activities been investing in numerous startups. highest performance, lowest cost with our needs. They could see the We were selected as part of the liquid rocket engine for smaller other applications and the potential first Air Force Space Pitch Day in launch vehicles. Called the Launcher breakthrough for other rocket November 2019 for a $1.5 million E-2, it is an additively manufactured, companies, not just Launcher. As a contract to further the development 22,000 lbf thrust, LOX/Kerosene, result, the company’s machine, the of our Launcher E-2 engine. They are closed-cycle liquid rocket engine AMCM M4K, became available two boosting and supporting innovation, with a booster stage version specific years ahead of schedule, allowing combining their investment with impulse target (the measure of how us to develop the E-2 combustion external investments, with the goal of effectively a rocket uses propellant) chamber at the same time as having more capabilities and options of 326s (vac). The oxidiser-rich staged progressing our turbopump work.” for small satellite launches. Today, combustion design used offers The use of AM resulted in a our relationship is as the recipient efficiency gains by not wasting around revolutionary new design for the of an R&D award. Tomorrow, our 5% of propellant on powering the E-2 engine. Without this technology, goal is that the Air Force will be one turbopump. Haot explained, a company as small of our largest customers to deploy Whilst these engines are set to as Launcher would not have been small satellites. NASA is currently power Launcher’s own Rocket-1 able to manufacture a combustion a service provider. We have a Space launch vehicle, they will also be chamber with such a thrust in Act Agreement to leverage the use available to third parties and, it is this time and with these costs. of its testing facility and teams at hoped, become a crucial propulsion “Moreover, if traditional technolo- NASA Stennis, and we pay for those system for a much wider range of gies such as brazing were used, services.” launch vehicles. This wider market, the characteristics of our chamber,

Fig. 5 Launcher’s Andre Ivankovic helps prepare the E-2 for testing (Courtesy Launcher/John Kraus)

such as heat transfer parameters from the material’s high conductivity would be able to manufacture our and hydraulic loss, would be and efficient cooling, leading to a chamber in copper alloy rather than worse, despite the significantly longer chamber life and reduced Inconel, but had not come across a higher cost of these technologies.” costs when compared to conventional service provider with this capability. manufacturing methods. The copper Copper alloy is widely accepted as E-1: the scale prototype and the switch from Inconel to copper alloy Development of the full size “...we were always hoping that one day E-2 engine was preceded by the we would be able to manufacture our E-1, a fully-functioning smaller prototype that was used to chamber in copper alloy rather than thoroughly evaluate and test all Inconel... Copper alloy is widely accepted aspects of the engine’s design. Initially, it was planned that the as the highest performance material for E-1 and E-2 engines would be built from Inconel; however, at cooling liquid rocket engines – Inconel is an early stage in the project the a compromise.” team discovered the work being done at 3T-RPD, now 3T Additive Manufacturing Ltd., in the UK on part proved to be twenty times more the highest performance material the processing of copper alloys by conductive than the comparable for cooling liquid rocket engines – PBF-LB. They approached 3T-AM Inconel part. Inconel is a compromise. When we to exploit the benefits of this Haot explained, “As part of our heard that 3T-AM was able to do this, material and, as a result, the use pursuit to build the highest-perfor- we immediately partnered with them of the standard C18150 CuCrZr mance AM liquid rocket engines, we and went from quote to successful alloy allowed the engine to benefit were always hoping that one day we test fire in less than eight weeks.”

Going big: moving from the E-1 to the E-2 Launcher’s engine development programme has relied on the ability to ‘scale up’ the engine, from the smaller E-1 to the full size E-2 that we see today. Commenting on the challenges that this scaling up presented, Haot stated, “With the same operating parameters such as fuel, pressure, mixture ratio, etc, it is easier to provide cooling of a large combustion chamber. Thus, we were comfortable about the strategy of moving from the E-1 to E-2. Larger internal cooling channels are also easier to build and to clean of powder. On the other hand, for a larger combustion chamber, it is more difficult to build walls and manifolds with the necessary strength; in addition, large chamber volumes can lead to high-frequency combustion instabilities, a process that can cause overheating and destruction of the chamber. Thus, it is not possible to simply enlarge the Fig. 6 Testing the E-1 engine. The blue mach or ‘shock’ diamond pattern in combustion chamber dimensions the supersonic exhaust plume is evidence of the efficiency achieved (Courtesy in scale and hope that it will work. Launcher) However, thanks to our experience and a world-class design team, Launcher can handle these kinds of challenges easily.” Crucial to this stage of the project was the development of process parameters for the production of a metre high CuCrZr combustion chamber on the newly developed AMCM M4K machine. AMCM’s Christian Waizenegger explained, “The development of process parameters for CuCrZr was one of the key elements for the success of this project. This development needed to take into account all the post-processing steps and ensure that the required material quality was still met. The materials and process development department of EOS in Finland played a key role in this aspect. They have decades of expertise and access to dedicated materials that allows them to develop the optimal process chain. The process development was achieved using a two-phase approach. First the processes were developed on Fig. 7 The E-2 engine combustion chamber after heat treatment and Hot an AMCM M290 1 kW, a system with Isostatic Pressing (HIP) on a Quintus Technologies HIP system at Accurate similar laser and optics configuration Brazing Corp’s Greenville, South Carolina, facility (Courtesy Launcher) to the M4K-1, but with the advantage

Fig. 8 Launcher E-2’s first ignition and test (Courtesy Launcher/John Kraus)

of offering an easier operation machine, process/parameters and Because of our liquid oxygen cooling throughout a development project. material are supported by a supply and high combustion efficiency of In the second phase, the process chain with multiple customers and greater than 98%, you only see a was ported onto the M4K-1 and first service bureau vendors offering the blue plume, which relates to the samples produced in order to confirm printer and material.” combustion products (water, CO, CO2). material quality. Heat treatment Most, if not all, of the yellow-burning was also a key factor in the project’s Test firing the E-1 and E-2 kerosene is combusted inside the success. This process step was an Test firing of various prototypes of chamber. As a result, this blue plume integral part of the application’s the E-1 engine took place in 2018 is a confirmation of the unique development and without this holistic and 2019 and included investigating efficiency of E-1.” approach to both the build process the performance of different build The first E-2 test campaign took and subsequent heat treatment, the parameters such as powder layer place in October at NASA’s Stennis project would probably not have been thickness, and, as a result, build Space Center in Mississippi. In this successful.” speed and build cost. These tests campaign, three test fires were The final heat treatment and Hot demonstrated that the E-1 engine performed. The first two tests used Isostatic Pressing (HIP) cycle for design achieved 98%+ C*. an uncooled copper replica of the the E-2 has been custom developed As can be seen in Fig. 6, the blue combustion chamber to reduce by Launcher to reach its specific mach or ‘shock’ diamond pattern risk and fully evaluate the additively material property goals. Haot stated, in the supersonic exhaust plume is manufactured injector’s performance. “Our design and the pace of process evidence of the efficiency achieved Both tests were successful and innovation within our team are the in the E-1. “All Kerosene engines confirmed the performance of the AM proprietary aspects of our products. typically have a yellow plume due to injector, the test stand equipment, We hope, however, that many propul- fuel film cooling or low combustion and the avionics systems. sion companies choose this material efficiency, which means unburnt fuel The first test firing with the fully and machine platform to ensure its leaves the combustion chamber and assembled AM combustion chamber long-term support and advancement. combusts outside the nozzle, thereby was partially successful, however Our strategy is to ensure that our AM creating a yellow plume/flame. it had to be terminated because of

Fig. 9 Launcher’s Chief Designer, Igor Nikishchenko, preparing the E-2 for test firing (Courtesy Launcher/John Kraus)

areas of restricted flow in some of The rocket scientist’s Chief Designer in the Liquid Propul- the cooling channels. “Now that our perspective: Launcher’s sion Department at Yuzhnoye, the Launcher E-2 engine test stand is Chief Designer, Igor Ukrainian state-owned company that built and ready to go – reaching test designed the Zenit launch vehicle, as four with a new chamber in March Nikishchenko well as the RD-8 oxidiser-rich staged 2021 will be about 5% of the cost combustion liquid rocket engine. and effort that it took to reach test Many of the world’s highest perfor- Yuzhnoye is also the designer and number one,” commented Haot. mance booster liquid rocket engines subcontractor for the first stage of the Whilst the combustion chambers were designed in the 1980s by teams Northrop Grumman Antares launch are the ‘star of the show’ when it based in Russia and Ukraine. The vehicle. More recently, he worked in comes to the application of AM in results of these achievements by Italy for Avio, a key contractor for the rocket systems, it is by no means scientists and engineers in what European Space Agency’s Ariane and the only AM application. There is, was then the Soviet Union remain Vega launchers. however, a recognition that there unrivalled and are still in production During his career, Nikishchenko needs to be a solid case for the move to this day, notably in the form of NPO has been involved in the design and to Additive Manufacturing. “AM will be Energomash’s RD-180, still used for development of propulsion systems used where it makes sense for us. For the first stage of America’s Atlas V for various launch vehicles, including the engine, this includes most parts rocket. hypergolic gas generator cycle of our pumps, turbine, and some valve In 2018, Launcher tapped into this engines and LOX/Kerosene Ox-rich components. In terms of structures rich heritage with the appointment staged combustion cycle booster such as tanks, we believe that the of Ukrainian rocket scientist Igor engines with thrust levels ranging traditional manufacturing techniques Nikishchenko as its Chief Designer. from 4,500 lbf to 270,000 lbf. available are lower cost and higher Based at Launcher’s New York City With the Launcher engine, the quality than some of the 3D printed headquarters, Nikishchenko has challenge he faced was delivering vehicle tank attempts you might see; over thirty years of experience in the efficiency of engines such as we are therefore not seeking to use high-performance liquid rocket the RD-180 in a much smaller AM for that.” engine development. He was Deputy form factor. Commenting on the

target of reaching as close to maximum theoretical efficiency as possible, Nikishchenko told Metal AM magazine, “Thanks to Additive Manufacturing, optimally-shaped cooling channels, which combine high heat transfer with low hydraulic losses, can be created in the combustion chamber. The creation of such channels using traditional technologies would result in very high costs for machining and subsequent brazing. So with AM, we needed to first create an optimum 3D model as our target. To estimate combustion efficiency in rocket engines, the efficiency factor C* is used. This coefficient for the E-2 engine should reach 0.98, which is close to the theoretical limit value of 1.0. Of course, such efficiency is not something incredible and has already been achieved in some modern rocket engines, for example, the RD-180. But it should be remembered that the E-2 engine is much smaller, and the efficiency of smaller engines is usually lower, C* =0.93–0.95. And besides, it Fig. 10 View showing the internal surface of the E-2 combustion chamber must be a very low cost engine.” (Courtesy Launcher/John Kraus)

Embracing new technologies: opportunities and approaches Nikishchenko continued, “As be the most efficient of the additively very conservative, because the mentioned, one of the most chal- manufactured chambers.” performance of an engine has been lenging tasks in the development of When considering whether rocket achieved with great difficulty, but rocket engines is the production of designers are inherently conserva- can often then be destroyed as a combustion chambers with narrow, tive or adventurous, and how AM fits result of a completely minor change; complex-shaped channels used for between these positions, Nikish- one which, at first glance, should cooling. The mechanical processing chenko stated, “I would say yes and not affect anything. So, I think most of such channels, and especially their no. In the early design phase, vehicle of the traditional rocket engine subsequent enclosure, is a difficult designers are often very adventurous manufacturers will proceed with technical challenge. For many years – they have to be, because there may some caution when introducing AM I thought about the possibility of a appear to be no way to overcome a into the production of these engines.” cheaper solution and then, just a few problem and create a solution. In a years ago, the opportunity to solve this rocket, heat capable of melting the A history of metal powder-based problem appeared – Additive Manu- most resistant of refractory metals parts in rocket engines facturing. Unfortunately, so far only is separated from the cold of space Nikishchenko commented, however, relatively small combustion chambers by a 1/25 inch thick copper wall. The that whilst a new technology such can be manufactured using AM, only reason why the wall doesn’t as AM may be greeted by some with and the choice of materials is also melt instantly is because heat is a level of caution – as is the case limited - until only recently, copper absorbed on one side faster than it is with all innovation – it can also be alloys could not be easily processed by supplied on the other one. Imagine regarded as an evolution of Powder AM. Therefore, I am very pleased that that you are sitting in a bottomless Metallurgy (PM) -based processes it was Launcher who contributed to boat and draining the water faster that have been successfully used by the creation of the world’s largest AM than it flows.” rocket designers for decades. “This machine capable of processing copper “But once the solution to a is the destiny of any innovation: at alloys, the AMCM M4K. Using it, we problem is achieved – and usually the beginning no one understands have made the largest copper-alloy this requires a lot of money and why this is necessary, and, after combustion chamber, which will also time – rocket scientists become a few years, no one can imagine

Fig. 11 A control room at NASA’s Stennis Space Center during E-2 testing (Courtesy Launcher/John Kraus)

the modern world without it. As – is still needed today to remove any internal channels and manifolds for Additive Manufacturing, what residual porosity from AM parts. So, that, otherwise, would be fabricated could be seen as the precursor of space vehicle designers knew about as separate components and added this technology has been used for the capabilities of metal powders by welding. It should be noted that rocket engines for several decades and applied PM technologies long even the perceived weak points of before the invention of what we today before the current more widespread AM technology, such as high surface also call 3D printing. The Soviet use of AM.” roughness, played a positive role RD-170 engine pump impellers in the design of the combustion were manufactured using the near Opportunities expected and chamber: a rough surface in net-shape Powder Metallurgy unexpected channels can significantly increase process of Hot Isostatic Pressing. When it comes to application devel- the heat transfer to the cooling liquid Whilst this is not AM as we know opment by AM, the technology offers and, therefore, in some conven- it today, it is nonetheless, in the some well-understood advantages: tionally manufactured engines, broadest sense, an ‘additive’ rather namely, design freedom to achieve combustion chamber channels are than ‘subtractive’ manufacturing unique shapes (including internal processed in a special way to obtain process. In this process, the metal channels, etc), speed of manufacture artificial roughness. In our case, we powder is not fused with a laser, for larger and more complex items got this improvement for free. And but loaded into a special container compared to conventional technolo- of course, no traditional technology, that is prepared to the required gies, and the ability to consolidate containing numerous stages of shape. This is then subjected to multiple components into one part. stamping, machining, brazing, high pressure and heat – so Hot Commenting on how each of these welding and then again machining, Isostatic Pressing – to densify it, and benefits has been leveraged by would have allowed a practically then the container is removed. The Launcher, Nikishchenko stated, “All finished combustion chamber to be laser now eliminates the need for of the AM technology advantages created from scratch in two weeks, this container, but HIP – as a heat you listed have been applied to even if we assume that we would treatment process rather than as a the design of the E-2 combustion have all the machines necessary for forming technology in its own right chamber. It contains both shaped this.”

New alloys for AM In many applications for AM, the use of a standard alloy as used in general manufacturing has proven to be highly successful; however, it is anticipated that new alloys custom-designed for AM will bring further advantages in the future. “We are now at the very beginning of the triumphant progress of AM technology. Therefore, attempts are mainly made to use previously-developed alloys that have proven themselves well in traditional manufacturing methods. At Launcher, for example, we were one of the first to use a CuCrZr alloy for additively manufacturing combustion chambers. In the future, I do not exclude the creation of alloys specifically designed for AM which will allow either increased freedom in the build process, for example by eliminating support when printing overhanging elements, or improved the strength of materials by, for example, reducing porosity,” stated Nikishchenko. Fig. 12 AMCM’s large-scale PBF-LB machine, the M4K, is based on the EOS AM’s contribution in context M 400 platform but allows for builds of up to 450 x 450 x 1000 mm (x, y, z) Commenting on his experience (Courtesy AMCM GmbH) of rocket systems development and putting AM’s role into context, Nikishchenko told Metal AM, “I want to say that the new generation of builder and its customer. The story of nor a process for the CuCrZr material launch vehicles, or rather, companies Launcher and AMCM is no exception that would later be selected, existed. involved in their development, are and the results of such collaborations We saw it as a challenging project, but appearing not only thanks to AM. can bring rewards for all parties. In had the feeling that Max and his team Many industrial advances, such as the case of AMCM, the reward has were the ideal partners to go through miniaturised electronics, semicon- been the ability to launch to the open such a journey with.” ductor lasers, the Global Positioning market the AMCM M 4K-4 machine “We started developing a large- System [GPS], increased demand for after development testing on a very scale printer – the M4K – based on satellite launches and satellites, have challenging application. the existing EOS M 400 platform. driven this. In addition, lightweight As AMCM’s full name (Additive The goal was to modify the machine and reliable control and orientation Manufacturing Customized Machines) to allow for build jobs of up to 450 systems, and composite materials for suggests, the company specialises x 450 x 1000 mm (x, y, z), with as lightweight tanks, have been created. in the customisation of PBF-LB few changes as possible so that the After all, the success of SpaceX systems from EOS GmbH for special machine could still build parts that inspired many. AM is significant, but applications. When Launcher decided were developed on the original M 400 not the main source of new opportu- to partner with AMCM GmbH, it was system. We then also developed the nities in the space industry.” on the back of a promise to deliver needed processes for CuCrZr in close the necessary one metre build height collaboration with our colleagues required for the E-2’s combus- from EOS Finland.” AMCM: the machine tion chamber. AMCM’s Christian Process development was initially builder’s perspective Waizenegger told Metal AM magazine, started on the AMCM M290 1 kW, “Back in 2018, Max contacted us a modified EOS M290 with a single As with so many application success with the request for a large-scale AM 1 kW laser, and the first small-scale stories in metal Additive Manufac- system capable of printing a complete samples were produced to check turing, they arise as a result of close combustion chamber. At that point material quality, to optimise process collaboration between a machine in time, neither a system of this size, productivity and to align with post-

ten days when built on a single 1 kW system (M4K-1). Considering the very large size of the part and the amount of material that is melted, this is a very high level of productivity. During process development our focus was on delivering the highest productivity possible at the required final density. Productivity could be even further improved by using a multiple-laser system such as the M4K-4 with 4 x 1 kW lasers; however this has not yet been tested with Launcher. We have to always remember, however, the fact that a combustion chamber built using the conventional technologies requires several months and the combination of multiple processes to be completed. In this sense, the AM technology used to produce the E-2 combustion chamber is already miles ahead of the conventional path. That is without considering the amazing improvements, in terms of combustion efficiency, that can be reached with AM designs.”

Unique challenges Commenting on the most significant challenges from a machine builder’s perspective when developing such a large application, Waizenegger Fig. 13 Digital render of Launcher Light. The company’s goal is to have its stated, “The time frame of this first test flight in 2024 and to reach orbit and be profitable in 2026 (Courtesy project – only ten months from start to Launcher) first prototypes – was one of the most challenging constraints for this project. We needed to ensure we kept up with the ambitious rhythm set by Launcher processing steps.“Once the first M4K Productivity and build time but, at the same time, deliver the prototype was available, we trans- Commenting on the challenges of expected quality. We therefore put a lot ferred the process onto the system productivity and cost when it comes of effort into identifying upfront all the and produced the first real-size parts to an application such as the E-2’s major elements needed for success, in to allow Max and his team to perform combustion chamber, Waizenegger order to avoid multiple system design further tests and optimisations on the stated, “Productivity is key to this loops. At the same time, we decided design of the combustion chamber. application. Surprisingly, the main to build a ‘Minimum Viable Product’ Finally, we produced the real combus- reason is not only the cost per part – as a first step, to then design the final tion chambers that Launcher used for something that everyone needs to be system. This was the best compromise its tests.” as low as possible – but also the fact to accelerate the project but keep the Whilst built on the proven EOS that so many of these rocket engines needed quality constraints. A further M 400 platform, the AMCM M4K’s will be needed in the future. Thus, a challenge was the handling of very big custom features include a more technology is needed that allows us loads of powder – easily 1.5 tonnes – in robust frame design, a new filter to cover the client’s needs in terms the build chamber. Ensuring a stable system (RFS 2.0), and optional of number of combustion chambers and precise z-position of the build soft recoater. The AMCM M 4K can produced over a period with the plate, even under such high loads, produce parts from a wide range lowest investment in terms of number required a dedicated system design. of materials, including aluminium of AM systems required.” The robust and welded M4K frame and (AlSi10Mg), nickel alloy (IN718) and “The build time of the E-2 body is designed to handle such high copper alloy (CuCr1Zr). combustion chamber is approximately loads without any compromise.”

Process stability and the wider AM of PBF-LB production,” stated project and contract to CuCrZr, even if workflow Waizenegger. it meant more investment in param- The need for process stability on such The availability of peripheral eter and material development.” large, high-value applications is, in devices that are suited to handle such “We were also very lucky not to many aspects, much greater than part sizes is crucial to an applica- be working with a team customising on smaller items, where a build time tion’s success and, commented a machine blindly, but with a team might be in hours rather than a week Waizenegger, should not be taken that developed the product they are or more. Waizenegger stated, “Worst as a given. As well as working with customising – the EOS M 400 - and case would be a job interruption Volkmann GmbH for the powder have access to the design and source right before the end of the build, sieving and conveying solution, AMCM code to make the necessary modifica- after several days of manufacturing. worked with Solukon Maschinenbau tions. This gave us a lot of confidence Process and machine reliability is key GmbH, also based in Germany. that they would be able to make it to avoid such situations. Our system Solukon provided the depowdering happen.” is based on the EOS M 400, a system solution needed to operate in “The key to this project’s success that has proven to be very reliable conjunction with the M4K. to date has been the close coopera- over several years. We took care to tion between the Launcher team and change as few elements related to the AMCM/EOS team,” stated the process as possible. The build Conclusion Waizenegger. “Together, we jointly chamber itself is 98% identical to the defined the required outcomes of the M 400 and the processes from the There is no doubt that the space project and communicated openly M 400 can all be ported to the M4K. sector will become an ever more about project risks and mitigation Whenever possible, the necessary important market for metal Additive actions, so as to ensure that all additional modules were chosen from Manufacturing and, as with the 20th parties have realistic expectations of the EOS portfolio – this is the case, century’s Space Race, technologies the timeline and results of the project. for example, for the filter units on the developed on the journey will quickly Crucially, all parties stayed as flexible M4K. Doing so allowed us to rely on feed through to more everyday appli- as possible when it came to changes proven elements that are known to cations. The cooperation between that were needed to ensure success be stable and to perform under very Launcher and AMCM is a good – because at the end, we can only be demanding conditions.” illustration of this and the resulting successful together.” “Special care has also been given developments in both materials and to powder management, as a job process technologies will no doubt interruption due to powder short enable a further widening of AM’s Contact and further feed would ruin the entire build job. application portfolio. information The sieving and conveying of large Whilst the development of combus- amounts of powder over several days tion chambers by AM is by no means Launcher without interruption is a require- unique, what this story illustrates very Follow Launcher via ment, and the solution must also be well is how AM has helped to open up www.launcherspace.com, on Twitter adapted to the exact scenario found a sector such as the space industry @launcher or on instagram at a customer’s facility – for example not only to private enterprise, but to @launcherspace gravity feed or conveyor feed, batch small organisations as well as the processing or continuous processing.” industry’s giants. Development time AMCM GmbH AMCM stated that it worked with has been dramatically reduced, as www.amcm.com German metal powder handling have the costs and manufacturing [email protected] specialist Volkmann GmbH to design time needed for each combustion and deliver solutions compatible with chamber – all whilst delivering the M4K systems. exceptional levels of performance. None of the above work, however, Haot concluded, “Working with can deliver success if the part being AMCM has been incredible, with built hasn’t been design-optimised delivery ahead of schedule and for AM. “Design for AM is key to avoid expectations met every step of the job crashes. We therefore simulated way. They’ve demonstrated extreme the designs from Launcher and built flexibility to our adapting needs and critical sections of the design to requirements. When we started the validate those simulations. Through project, our first contract specified iterative design loops we optimised Inconel 718, but after great results the application’s design, together with with CuCrZr with our subscale E-1 the team from Launcher, to ensure engine, AMCM saw the benefits and that it conformed to the requirements potential and agreed to switch the