3D Printing is revolutionizing space exploration and this is only the beginning. From lowering the cost of prototyping and working spacecraft and launch vehicle parts - to enabling new kinds of designs and capabilities...the future is looking good. We believe 3D printing is going to democratize the Aerospace Industry in a similar way that PC's revolutionized the computing industry. Do you know of a company, technology or new innovation we didn't include? Let us know and we'll add it.
Direct Metal Laser Sintering (DMLS)
A sub-category of Selective Laser Sintering (SLS) – traces its roots back to a description and patent filed by Pierre Ciraud in the early 1970s. Iterations of the process popped up again and again throughout the decades that followed until, in 1994, the EOS firm of Munich, Germany developed a commercial technology that directly incorporated DMLS. Though the terms generally mean the same thing, SLS is, by-and-large, the term used for the laser sintering of plastics while DMLS is used to – as its name implies – refer to the laser sintering of metals.
Much like Selective Laser Sintering (and every other additive manufacturing method), Direct Metal Laser Sintering is guided by a 3D blueprint (most often a CAD file) that allows the designed object to then be divided into its constituent layers. The layer’s thickness is determined by the equipment being used but is often in the 20 to 40 micrometer (µm or micron) range. After the 3D blueprint has been produced and sent to the DMLS machine, the build process is ready to commence. The process begins when a layer of powdered material is deposited on the build platform. Then the laser fuses the powdered material at specific points, or over a range of points, according to instructions provided by the blueprint. When the first round of sintering is finished, another layer of powdered material is deposited on top and the laser again fires at specific points to form a solid mass with the layer below.
The most widely used materials in the DMLS process include 17-4 PH and 15-5 PH stainless steel (the “PH” stands for Precipitation Hardened and the “17-4” refers respectively to the percentage of chromium and nickel added to the alloy), cobalt chrome (CoCr), titanium (Ti64), and Inconel[i] 625 and 718.
The fact that the DMLS process builds a part from the bottom up allows for the direct manufacture of internal features (projections, passages, threads, etc.) that would be impossible to cast with traditional methods or machine with existing technologies. Similarly, DMLS makes it possible to reduce the number of separate pieces involved in constructing complex and multi-component geometries because the part can be manufactured as one unit rather than assembled from constituent elements. In a more general sense, DMLS-produced parts do not require pre- or post-run tooling like those produced in the casting process. This makes DMLS ideal for single and small-quantity production runs because it reduces the total labor and time involved in the process. [i] Inconel is the trademarked name of an austenitic nickel-chromium superalloy that is well suited for extreme heat and pressure environments because of its oxidation and corrosion resistant properties.
Electron Beam Freeform Fabrication
(EBF3 or EBF3 depending on your fondness for superscript) is an additive manufacturing process developed and engineered by Karen Taminger for NASA Langley Research Center (LaRC). NASA saw the need for a portable, low mass, low power apparatus capable of three-dimensional replacement part fabrication, especially as it applies to remote locations where spare parts are not logistically available (a.k.a. space).[i] Development of an installed EBF3 system began in 2001and progressed rapidly through 2002 and 2003 when the design team began work on a more advanced, portable EBF3 system. The portable EBF3 system then underwent rigorous microgravity (parabolic flight) testing in 2006 and 2007 in preparation for future testing in 0g vacuum environments (a.k.a. space).
Electron Beam Freeform Fabrication starts with a computer-aided design (CAD) file that supplies 3-dimensional information (X, Y, and Z) of the part to be produced. Like other additive manufacturing processes, the 3-dimensional model is also divided into cross-sections (layers) of between 0.5 mm and 1.27 mm (500 µm to 1270 µm). When the EBF3 process begins, a metal wire is fed into an enclosed vacuum chamber where an electron-beam gun melts the wire according to specifications within the CAD file. When the first layer is complete, the on-board computer moves to the next layer where the metal wire is fused to the previous level. This process continues until the part is complete.
EBF3 has demonstrated production using a wide variety of metals including pure aluminum (Al), pure titanium (Ti), titanium and aluminum alloys, and Inconel 718. NASA has also demonstrated e-beam welding using pure copper and pure niobium suggesting future applicability to EBF3. Theoretically, any weldable alloy – with the exception of magnetic ferrous (iron-based) alloys – could be used in the EBF3 process. Gold (Au), silver (Ag), and platinum (Pt) are prime candidates for future use in this manufacturing process.
One of the key benefits of EBF3 is that it can be performed in a vacuum without extensive modification to the process. Earth-based EBF3 must induce a vacuum within an enclosed aluminum container. Production, then, is limited to the location and size of the build vacuum available. Space-based EBF3, on the other hand, is free of this constraint (because space is one big vacuum). As a result, there is no limit on the size of the part being constructed and the process can literally be conducted anywhere. Scalability of the manufacturing unit is another major benefit of the EBF3 technology. The complete portable unit (on Earth) can be as small as an office desk but smaller units can be deployed through the use of an umbilical that provides power and vacuum. Space-based units can be as large or as small as necessary per build requirements. Flexibility is another benefit of the process. Because two or more wires can be fed into the system, EBF3 can manufacture multi-material parts, including new alloy-based parts or layered parts with better surface properties. Other benefits of the process include decreased cost – both of the unit itself and the material used. According to the NASA website: …cost savings are possible because of the NASA system’s reduced use of material. EBF3 uses a full 100% of the material for the part with no residual material contamination. This offers an advantage over powder-based e-beam systems, which require residual material to be recaptured and recertified before reuse. Parts made with NASA’s EBF3 system can be used or shipped immediately with only minimal need for cooling.
Stereolithography (SLA or SL)
Literally means three-dimensional printing, was a term conceived by Chuck Hull in the mid-1980s and used to describe a working method (and the associated technology) for the layer-by-layer manufacturing of three-dimensional objects using a laser and a liquid photopolymer material. Hull and his stereolithographic method could be considered the progenitor of the modern additive manufacturing (3D printing) industry: the commercialization of stereolithography through Hull’s newly-founded company 3D Systems is often credited with inspiring many of the subsequent developments including selective laser-sintering (SLS) and direct metal laser-sintering (DMLS).[i] While Hull’s stereolithography was originally intended to encompass any material capable of solidification or of altering its physical state, the term has now become synonymous with production through a liquid medium.
The first step in stereolithography – or any additive manufacturing process, for that matter – is the preparation of a 3D digital description of the object to be produced. This digital description most often takes the form of a computer-aided design (CAD) file and not only renders the object in three dimensions (X, Y, and Z) but also divides the object into layers ranging in size from 50 to 150 micrometers (µm or micron). After the CAD file has been downloaded to the hardware’s internal computer, a small layer of liquid photopolymer material is spread across the build platform. An ultraviolet laser then cures the liquid material according to the digital description by tracing a cross-section of the first layer. When the first cross-section is complete, another layer of liquid photopolymer is applied – or the platform is lowered further into a vat of the material – and the laser again cures the resin according to the digital description and joins it with the previous layer. When the process is complete, support structures are removed and the part is immersed in a chemical bath for cleaning. Finally, the piece is cured further in an ultraviolet oven.
The primary medium used in stereolithography is the photopolymer. Photopolymers are manufactured macromolecules that change properties (i.e., cure or, more simply, link together and harden) when exposed to ultraviolet or visible light. Photopolymers can be manufactured to exhibit different traits – durability, high detail, stiffness, etc. – when cured and many companies make use of proprietary mixtures.
A major advantage of stereolithography is the speed at which parts can be produced. Most functional parts can be manufactured within a day but build times often depend on the size and complexity of the finished piece. Parts produced through stereolithography can be machined and used as prototypes for more traditional, long-run manufacturing processes. Commercial stereolithography machines range in price from $100,000 to more than $500,000 but increased public interest has recently moved the market to release several consumer-oriented models with significantly smaller price tags. In addition, the cost of the photopolymer material has recently begun to decrease in price from $80-$120/quart (1 quart = ¼ gallon = ~1 liter) to $40/quart.
Selective Laser Sintering
SLS for short, was developed in the mid-1980s under the auspices of the Defense Advanced Research Projects Agency (DARPA). Dr. Carl Deckard and Dr. Joe Beaman – then working at the University of Texas at Austin – patented the process and began marketing and manufacturing the SLS machine under the moniker DTM. The last patent associated with the original SLS technology expired in early 2014 making this method of 3D printing more accessible to the general public.
Methods of Selective Laser Sintering
Selective Laser Sintering uses a 3D digital file or blueprint (e.g., a CAD file or a simple surface scan of a pre-existing object) and a high-powered laser to heat and fuse small particles of powdered material into the desired three-dimensional shape. At the beginning of the process, a roller pushes a layer of powdered material from a storage reservoir onto an adjacent platform called the powder bed. The high-powered laser then selectively heats and fuses the powdered material according to the specifications for that layer found in the digital blueprint. When that layer is finished, the powder bed is lowered by the thickness of a layer, the roller pushes another layer of powdered material on top of the previous layer, and the laser again selectively fuses the material into a solid mass. The process is then repeated in this manner until the object is finished.
Materials Used In Selective Laser Sintering
SLS can make use a wide range of powdered material including nylon, polystyrene, green sand (a composite of silica, bentonite, water, inert sludge, and anthracite), titanium, steel, and other alloys. Currently, nylon (and its variants) is the most widely-used material for the SLS process. Variants include carbon-fiber-filled nylon, flame-retardant nylon, glass-filled nylon, impact-resistant nylon, and rubber-like nylon.
Benefits of Selective Laser Sintering
Additive manufacturing processes such as stereolithography (SLA) and fused deposition modeling (FDM) lay down layers of material in a vertical orientation on an empty, horizontal surface. To produce an object with a feature that protrudes laterally to a significant degree from the middle of the parent mass (say an outstretched arm) would require a support structure built up from the base so the heated, liquid material would have something to sit on. SLS, on the other hand, can produce complex, “stalactite-like” features without the need of support structures because the feature under construction is surrounded on all sides by un-melted powder and is literally being carved from the surrounding material. Other benefits of the SLS manufacturing process include weight reduction and the consolidation of individual parts into one integrated structure.
Fused Deposition Modeling
FDM, was developed and patented in the late 1980s by S. Scott Crump who, in the early 1990s, commercialized the process for industrial applications through his manufacturing company, Stratasys Ltd. After the patent on this technology expired – and prices started coming down – FDM developed into one of the most popular techniques for the new commercial and DIY 3D-printing industry. As of this writing, FDM continues to evolve and grow via a healthy open-source development community.
Methods of FDM
As with most manufacturing, FDM begins with a blueprint. In the case of 3D printing, that blueprint often takes the form of a stereolithography (STL) or computer-aided design (CAD) file. The 3D blueprint provides instructions to a 3D printer in much the same way that the word-processing software on which this article was written provides instructions to a 2D printer. While the word-processing software only supplies information for two dimensions (X and Y), the 3D blueprint includes information for three (X, Y, and Z). Once the digital blueprint has been supplied to the 3D printer’s on-board computer, the raw material – typically in the form of a plastic or metal filament - is forced into the nozzle where it is heated to its melting point in preparation for the extrusion phase. Then, following the blueprint’s specifications, the nozzle regulates the flow of the raw material and deposits it layer by layer to build the object from the bottom up. To illustrate this process, imagine baking a cake in the shape of a Mountain Dew ® can. How would you make this happen? The easiest way would be to bake a series of circular cakes and stack them one on top of the other. By dividing your Mountain Dew ® can cake in this way and assembling it from the bottom up, you are mimicking – on a much larger scale – the 3D printing process.
Materials Used in FDM
Fused Deposition Modeling makes use of a variety of thermoplastic materials including acrylonitrile butadiene styrene (ABS), polylactic acid (PLA), polycarbonate (PC), polyphenylsulfone (PPSF), polyetherimide (PEI), and others. Each material performs differently and exhibits its own list of traits. Some materials are heat resistant while others are fire retardant. Some materials produce stronger parts while others are better suited for producing small detail.
Benefits of FDM
The FDM process has become popular among DIYers because of the relative low cost associated with materials and hardware when compared with other processes. FDM produces an object that –because of its thermoplastic construction – exhibits a high strength-to-weight ratio, resists impact, and is most often waterproof. Another advantage of the FDM process is the option of utilizing multiple colors during production.
NASA’s Desert Research and Technology Study Rover
In the harsh environment of the Arizona desert, NASA is testing its Desert Research and Technology Studies (RATS) rover for possible inclusion in a future Mars mission. This rover, however, is very different from the batch of rovers currently exploring the red planet. For one thing, the Desert RATS rover is currently the size of a Hummer. Now before you go crying “Foul,” keep in mind that the Desert RATS boasts something that no other rover before it has had: a pressurized cabin that supports human life. With this rover – and other advances in technology - NASA is taking steps to reach the lofty goal of sending humans to Mars. And while this goal may seem like it would come with a fairly hefty price tag, engineers are keeping costs (relatively) low by utilizing the latest advances in additive manufacturing (a.k.a. 3D printing). NASA employed Stratasys – a global leader in additive manufacturing – to produce about 70 of the parts that make up the Desert RATS rover. Stratasys used fused deposition modeling (FDM) to form materials such as acrylonitrile butadiene styrene (ABS), polycarbonate-acrylonitrile butadiene styrene (PC-ABS), and other polycarbonate materials into flame-retardant vents and housings, camera mounts, large pod doors, the front bumper, and many other custom fixtures. According to Stratasys, “FDM offers the design flexibility and quick turnaround to build tailored housings for complex electronic assemblies. For example, one ear-shaped exterior housing is deep and contorted, and would be impossible – or at least prohibitively expensive – to machine.” NASA engineers chose 3D printing for various reasons including cost, weight, and strength of finished product. “You always want it [the finished product] to be as light as possible, but you also want it to be strong enough,” says NASA test engineer Chris Chapman.
Printing a Space Camera
In an effort to reduce the cost and build-time of lens-based space tools, NASA aerospace engineer Jason Budinoff is building both a camera and a telescope using 3D-manufactured components in the hopes that he can then produce the first 3D-manufactured telescope mirrors. The 50-millimeter (2-inch) camera whose outer tube, baffles, and optical mounts are all printed as a single structure will be mounted in a CubeSat and fitted with conventionally-fabricated mirrors and glass lenses before undergoing vibration and thermal-vacuum testing in 2015. The 350-millimeter (14-inch) dual-channel telescope – that Budinoff says is more representative of a typical space telescope – will also benefit from new advances in additive manufacturing and be the second step in the improvement of lensed tools. Budinoff then hopes to demonstrate that he can use powdered aluminum to produce 3D-manufactured optics. Under normal circumstances this would be extremely difficult, if not impossible, because aluminum is a porous metal. However, Budinoff believes that after 3D-manufacturing an appropriately-sized aluminum object, he can then subject it to a process called isostatic pressing – simultaneously heating the object and increasing the pressure to 15,000 psi – which will “squeeze” the mirror to reduce the surface porosity and render a polished, mirror-like surface. The development of the camera, telescope, and optics using additive manufacturing will be invaluable to anyone who builds optical instruments. “I think we can demonstrate an order-of-magnitude reduction in cost and time with 3D printing,” concludes Budinoff.
Rocket Injector Passes Test
A rocket engine injector, constructed by Aerojet Rocketdyne using additive manufacturing techniques, recently passed an important hot-fire test. The successful completion of this test moves 3D-printed parts one step closer toward being used in rocket engines. While 3D printing has been used in the past to produce parts for space vehicles, it is usually restricted to less critical components. According to Jeff Haynes, additive manufacturing program manager at Aerojet Rocketdyne, “the injector is the heart of a rocket engine and represents a large portion of the resulting cost.” Indeed, injectors may take a year or more to build but, using additive manufacturing technology, Aerojet Rocketdyne can reduce build times to less than four months while simultaneously cutting overall cost by 70 percent. Aerojet Rocketdyne used selective laser sintering (SLS) to liquefy and fuse metallic powder into the required specifications. The injector was then sent to NASA’s Glenn Research Center in Cleveland, Ohio where it underwent the crucial hot-fire tests. Upon successful completion of the tests, Carol Tolbert, Manufacturing Innovation Project manager, said, “These successful tests let us know that we are ready to move on to demonstrate the feasibility of developing full-size, additively manufactured parts.”
Made in Space and Zero Gravity 3D Printing
On Sunday, September 21, 2014, SpaceX launched its fourth Commercial Resupply Services (CRS) spacecraft – Dragon for short – into orbit on its way to rendezvous with the International Space Station (ISS). 53 hour later, at about 6:45 a.m. EDT on Tuesday, the Dragon capsule caught up with the ISS and was successfully captured and installed onto the Earth-facing port of the Harmony module. Later that same day, crew members began unloading and stowing the payload sent from Earth. One special package tucked safely into the Dragon’s payload represents the first step on a course of development that could revolutionize the future of space exploration. The special package in question is a 3D printer – the first ever scheduled to be used in low earth orbit. And while it may not be installed and ready for use until December, the mere fact that a 3D printer is now on the International Space Station is enough to make us just a bit giddy. Three days before launch, on September 18, 2014, the company that developed the 3D printer – Made In Space – made themselves available on Reddit for an Ask Me Anything (AMA) session where they discussed various aspects of the project and the future of the industry. Joining members of the Made In Space team were Jason Dunn, Chief Technical Officer of Made In Space, and Niki Werkheiser, In-Space Manufacturing Project Manager at NASA’s Marshall Space Flight Center. Made In Space was founded in 2010 in Mountain View, California where, according to Jason Dunn, “the core value of the company was that humans should be able to live off planet in a sustainable and independent way. The obvious end goal for Made In Space – and all space-based manufacturing – is one that enables humans to be independent from Earth.” The 3D printer is a major step in that direction. The Made In Space printer – aptly named the Zero-G Printer – was developed by first testing available 3D printers in micro-gravity-simulating, parabolic flights. Engineers discovered a number of issues that needed to be overcome so, with that knowledge, they built their model from the ground up specifically to operate in the closed-loop, zero-gravity environment of the ISS. The current model of the Zero-G Printer is small compared to terrestrial printers but Made In Space has announced that they are working on a larger iteration that will be commercially available to anyone on Earth sometime in 2015. The existing printer aboard the ISS, once installed, will be operated by a ground control team at Made In Space. By connecting through the space station’s computer system, technicians on the ground can remotely operate the printer to produce the desired results. Plans for new items can essentially be e-mailed from the ground to the printer’s on-board computer where they will be decoded and produced rendering wait times for replacement parts almost non-existent. But don’t expect anything ground-breaking right at first. The Zero-G printer must be validated in what NASA calls the Microgravity Science Glovebox (MSG) – a self-contained unit that provides a safe, contained environment for research with liquids, combustibles, and hazardous materials. Before being deployed full-time, a new technology must be tested in the MSG. The MSG also serves as a place for experiments to be conducted so you can imagine that the queue to get some time in this space is rather lengthy. Once in the Microgravity Science Glovebox, the first builds will be what the team calls “test coupons” which are designed to test the tensile strength, compression strength, flexibility, and other properties of the finished part. These “test coupons” will be shipped back to Earth for analysis and the build process updated to suit the findings. The Zero-G Printer itself isn’t all that much to look at but don’t let its size and simple design fool you. It’s a powerful tool that has the potential to revolutionize space exploration forever. The printer makes use of acrylonitrile butadiene styrene (ABS) plastic that is stored as a spool of solid filament. During the extrusion process, the plastic becomes very soft – but never quite liquid – and is assembled through a proprietary process similar to fused deposition modeling (FDM). As you can imagine, space is limited aboard a space station so concerns about recycling and reusing materials become paramount. Made In Space is developing a material recycler so that manufactured parts can be melted down and the material reused rather than being ejected into space. ABS plastics degrade very quickly in the vacuum of space so parts will have to be put to use inside the space station. Made In Space has, however, promised that the second, larger printer will be able to use multiple materials – perhaps even metals – some of which can be used in the harsh conditions outside the protective skin of the ISS. The build platform is contained within an enclosure called an Environmental Control Unit (ECU). This enclosure protects not only the build platform (from stray floating objects, let’s say) but also the user and surrounding environment. Should something go wrong during assembly, the build material and any other detritus would be contained within the ECU. According to Jason Dunn, building a 3D printer for space isn’t just about making it work in zero gravity; it also has to be safe enough for repeated use in a fairly volatile environment. Made In Space developed new technologies that deal with controlling the print environment, making it much safer to operate. This technology may even have useful applications for making earth-bound printers safer. So what does the future of space-based 3D printing hold? Niki Werk believes that, “this new technology will disrupt forever the severely constrained supply chain model that has been in effect since the inception of the space program.” This disruption is a welcome change from the norm because for longer-term trips and further-out destinations, the current supply model is simply not feasible. “The capability to make what you need, when you need it, wherever you might be has larger implications than we can even imagine today. 3D printers would allow for an on-demand “machine shop” that would make long-duration space missions more feasible. Imagine going to Mars and rather than taking along 200,000 spare parts, you just take a printer and a few hundred pounds of feedstock.” This certainly is an exciting development in a field filled with almost daily advances. The future of 3D printing – both terrestrial and zero-g – is poised to become, as someone once said, the third industrial revolution. Made In Space will no doubt be on the cutting edge of that revolution.
Spacex and Multi-Alloy 3D Printing
A SpaceX launch is becoming standard fare these days. But the launch on January 6, 2014 was just a tiny bit different. During that mission, one of the nine Merlin 1D engines that propel the Falcon 9 rocket contained a Main Oxidizer Valve (MOV) that had been built by a 3D printer. This marked the first time SpaceX had ever launched a 3D-printed part. According to a SpaceX representative, “[they have] spent the last 3 years evaluating the benefits of 3D printing and perfecting the techniques necessary to develop flight hardware.” This revelation comes hot on the heels of an announcement by NASA that they had successfully manufactured – using 3D printers, of course – a mirror mount made of several different alloys. And while this may not seem like a newsworthy event, consider that all 3D printing up until this time has been done using one material at a time. The new process allows a 3D printer working with different alloys to vary properties such as melting point and density at different ends of the object. Let that sink in for a moment. Using the new process, the properties of an object can differ from point to point depending on the alloy used at that point in the construction. Douglas Hoffman, a researcher in material science and metallurgy at Jet Propulsion Laboratory (JPL), states that this new process allows 3D printers to, “change the metal powder that the part is being built with on the fly. [This means that] you can constantly be changing the composition of the material.” The new technique deposits layers of metal on a rotating rod which allows transitioning metals from the inside out rather than adding layers from bottom to top as in the more traditional 3D-printing techniques. The possibilities for this new technology are endless and will benefit Earth-based industry with their sights set on more terrestrial matters as well as those industries – like SpaceX that might now incorporate more 3D-printed parts in their space vehicles – with their sights set a little bit higher.
Rocket Crafters Inc. – founded in 2010 by Paul Larsen, Ron Jones, and Steve Edwards – is working with Stratasys – a world leader in additive manufacturing – to produce hybrid rocket engines for their Direct-Digital Advanced Rocket Technology (D-Dart). Hybrid engines use a solid fuel and a liquid oxidizer that, when combined, produce the thrust necessary to propel a rocket. The hybrid engine offers the best of solid fuel – immediate launch and high thrust-to-weight ratio – and the best of liquid fuel – fuel efficiency, higher impulse, and the ability to be throttled and restarted – while increasing the safety performance of the engine as a whole. Even though hybrid engines are better in most cases, they have yet to see widespread use because of high development costs, inability to scale to high-volume production, and variable performance from one engine to the next. Rocket Crafters hopes to change all that.
Rocket Crafters and Stratasys are working together to combine Fused Deposition Modleing (FDM) and Composite Filament Winding (CFW) to produce a one-piece fuel grain/casing component. Traditional methods of casting the hybrid-fuel grains are labor intensive, require expensive mold tools, and demand extensive use of internal webbing to improve the grain’s ability to withstand stress. Using additive manufacturing eliminates many, if not all, of these problems. According to Ron Jones, chief technology officer of Rocket Crafters, “[the FDM process offered by Stratasys] and the acrylonitrile butadiene styrene (ABS) thermoplastic offered the ideal combination of an industrial scale fabrication platform capable of producing large grain sections in a high modulus, chemically stable polymer with excellent accuracy and throughput.” In concert with the FDM process, D-DART uses Composite Filament Winding to wrap the fuel grain and other motor components (pre-combustion chamber, post combustion chamber, and nozzle) in a high-strength carbon-fiber shell to form the solid section of the rocket. These new developments are helping to give hybrid engines the respect – and use – they deserve. Indeed, Ron Jones speculates, “[we are] creating the enabling technology for hybrid rockets to become the preferred choice for commercial spaceflight and many military applications. Additive manufacturing technology has been the key to producing fuel grains with higher consistency, at a lower cost and shorter lead times, than was ever possible in the past.” After development is complete, Rocket Crafters plans to test-fly its hybrid engines and begin the commercialization for military and commercial applications.
3D Printing Space Telescopes
Asteroid mining: Science fiction or science fact? Hint: Don’t be too quick to answer. Planetary Resources – whose ultimate mission it is to harness valuable minerals from asteroids – is already taking steps to make asteroid mining as commonplace as terrestrial mining.
They are teaming with 3D Systems – a world leader in additive manufacturing – to produce components for their Arkyd line of space telescopes. These telescopes – Arkyd 100, 200, and 300 - will be launched into Earth orbit where they will work like the prospectors of yore to identify and analyze prospective mining opportunities. Eventually, the company plans to build robotic spacecraft that will travel to near-Earth asteroids, extract precious materials such as metals and water, and return to Earth. 3D printing will play a major role in the production of both the telescopes and the vehicles that will travel to and from the asteroids. Avi Reichental, 3D Systems CEO is confident that, working together, the two companies can, “increase functionality while decreasing the cost of the Arkyd spacecraft.” Peter Diamandis, co-founder of Planetary Resources, had similar expectations. “Our vision of mass producing the Arkyd 100, 200, and 300 line will greatly benefit from their [3D Systems] thinking and technology.” The first Arkyd 100 is expected to launch in 2015 after a successful Kickstarter that raised $1.5 million. As thanks to all their backers, Planetary Resources is making the Arkyd 100 into the first publicly-accessible space object ever sent into orbit. Not only will it search for asteroids to be mined, it will also take space-selfies crafted from backer’s photos.
FutureEngineers.Org 3D Printing Space Challenge
The future is now! It sounds a bit cliché and it may be overused but the recent convergence of advanced technologies such as software, robots, materials, manufacturing methods, and (of course) the internet, have given rise to what many are calling, “The Third Industrial Revolution.” That’s a lot to live up to when you think about it. Previous industrial revolutions influenced almost every aspect of daily life on the planet. But, in fact, the process that has come to be known as digital manufacturing (a.k.a. 3D printing or additive manufacturing) does possess the power to change forever the landscape of what we can design and produce. And for the first time ever, this industrial revolution has the power to reach beyond our little blue marble into the vacuum of space, to other planets, and beyond. This isn’t just pie-in-the-sky talk like, “in the future, we’ll all have flying cars.” It’s actually happening right now. In fact, on September 21, 2014, NASA and SpaceX sent a specially-designed 3D printer manufactured by Made In Space to the International Space Station. Once tested and implemented, astronauts will be able to print everything from spare parts to food (that one is a few years down the road). Engineers on Earth can even e-mail new designs directly to the 3D printer rather than waiting for a scheduled rocket launch. Imagine the potential for 3D printing as we take steps toward sending the first manned-mission to Mars. How far will this technology take us? How can we best use this technology? What is its potential? These and many other questions have yet to be answered.
To help inspire future engineers and to get young people to dream about the future – and make those dreams a reality, the ASME Foundation and NASA have issued a challenge to all K-thru-12 students in the United States: Design a space tool. But not just any space tool; an essential space tool. This from the FutureEngineers.org website: The ability to 3D print in space is a game-changer for space exploration. Just think about it, when astronauts are on Mars, they will have the ability to make whatever they need, on demand, even though Earth is just a little blue glimmer in the sky. That’s exactly why we are challenging our next generation of explorers to start designing parts for space now. We want students to create and submit a digital 3D model of a tool that they think astronauts need in space. If you win, your design will become a part of space history as one of the first things ever to be 3D Printed in Space.
What You Need To Know
September 21, 2014: Program begans December 15, 2014: Entries closed January 16, 2015: 10 semifinalists announced January 23, 2015: 4 finalists announced January 30, 2015: Winners announced Contest rules, design guidelines, judging criteria and explanatory videos can be found on the FutureEngineers.org website. Keep in mind that the challenge was not to actually build the tool but to produce a digital design (like a computer-aided design file) that can then be used to produce the part in space. As astronaut Doug Wheelock said, “Think beyond wrenches and hammers.” Imagine yourself on Mars (which may not be as far-fetched as you think). What would you need to survive? What would be essential to your everyday life in that harsh environment? These are some of the questions at the heart of the challenge that only you can answer.
Selective Laser Sintering Patent Expires
On January 28, 2014, US Patent 5597589 expired moving a core process of the 3D printing world – Selective Laser Sintering or SLS – from private to public domain. But don’t expect cheap, personal SLS printers any time soon. Too many other patents still remain in effect making SLS into a veritable minefield of potential litigation for any company looking to get involved in the market. 3DPrint.com writer Eddie Krassenstein points out that 3D Systems – the owners of 5597589 – do make consumer-level 3D printers but none of them use SLS technology. What does that tell you? Something must be holding them back. Krassenstein also point out that most of the large 3D printing companies have known for years that 5597589 would be expiring today. Yet none of their entry-level models is designed to use SLS. An investigation of extant SLS patents must have turned up something that would prevent these firms from getting involved. It’s these actions that hint at what’s going on behind the scenes even as we lament the lack of a cheap, personal laser sintering printer. Needless to say, it will be interesting to watch the developments in the SLS field as the next two years unfold.
DIY Rocket Engine Design and 3D Printing with David Gregory
How does designing a rocket engine for 3D printing differ from an engine built using traditional manufacturing?
Designing for additive manufacturing is different. It opens up design space that isn't available with traditional manufacturing. But there are design rules and constraints that have to be considered at the very beginning of the design process. Trying to take a part that is already designed and then convert it to additive manufacturing is often problematic. Additive really shines when the part is designed from the start for additive.
The biggest challenges to designing for additive in my opinion are
CAD tools feel limited when designing for additive. The design software will need to grow in order to allow additive manufacturing to realize its full potential. Resisting the urge to keep iterating in the design phase. In additive parts, complexity is free in the sense that it doesn't add to the cost of the finished part. But complexity has a cost in design time. In the world of space exploration, the costs are often dominated by labor costs. Additive enables shorter design iteration loops so I think its best to make lots of hardware iterations, rather than trying to get it perfect in CAD the first time.
Do you face material constraints and does this effect your design?
Obviously there is not the full range of metal materials available for 3D printing right now. However, there are quite a few options and most of the categories are covered with titanium, aluminum, and nickel alloys. Again, designing for additive from the beginning is the key - selecting the an available material as a design constraint early in the process will ensure that the design is suited to the process.
What are your general thoughts on 3D printing related to space exploration?
I think that 3D printing will enable lower cost/performance technologies to developed by a wider variety of organizations and individuals. Space exploration will benefit directly from that shift through reducing time to market and opening up new design possibilities. To learn more check out David's website RocketMoonlighting.
Rocket Engine Costs Using DMLS
Manufacturing parts for a rocket can be expensive. While small-scale components might be relatively affordable, large-scale components can increase in cost by several orders of magnitude. Factors that weigh heavily in traditional, subtractive manufacturing include design, labor, materials, and pre- and post-production. In contrast to traditional methods, additive manufacturing methods (a.k.a. 3D printing) such as direct metal laser sintering (DMLS) and selective laser sintering (SLS), can produce the same part at a fraction of the cost. DMLS still requires a design stage but even this is simplified due to the ability of the process to construct complicated, articulating pieces as one unit rather than several. In addition, much of the labor involved in pre- and post-production is done away with because of the nature of the manufacturing process. If you were to manufacture a solid aluminum cube, you would pay for the production of a computer-aided drafting (CAD) file that serves as the blueprint for construction. You would also pay for the materials being used to construct the cube and you would likely pay a fee to use the machine that builds the cube. Essentially, the cost of a part is largely dependent on the volume of metal it contains. This is welcome news to the companies vying for a foothold in the new space race. By keeping manufacturing costs low, companies can do more with less and this looks good on the bottom line. 3D printing has also given the amateur rocket scientist the resources to do much the same work as the big boys…only on a smaller scale.
AlSi10Mg – an alloy composed of aluminum, silicon (the “10” means that silicon is 10% of the weight of the alloy), magnesium, and other elements – is a common material used in the direct metal laser sintering of parts for the automotive, aerospace, and engineering industry. Important properties include: High strengthHigh hardness (ideal for parts subject to high loads)High thermal toleranceLow weight
Cobalt Chrome MP1
Cobalt chrome MP1 is a superalloy (an alloy capable of withstanding high temperatures, stresses, and oxidizing atmospheres) composed primarily of cobalt, chrome, and molybdenum. Because of its properties, cobalt chrome MP1 is often used to produce parts for turbines (e.g., jet engines) and medical implants. Important properties include: High strengthHigh temperature and corrosion resistanceChemistry of the alloy allows the mechanical properties to improve as the temperature increases (up to 600 C)Nickel-free
Cobalt Chrome SP2
Cobalt chrome SP2 is a superalloy composed primarily of cobalt, chrome, and molybdenum. The SP2 alloy of cobalt chrome is especially useful in the dental industry. Important properties include: Biocompatible (meaning the body will not reject implants of this material)High tensile strengthHigh temperature and corrosion resistanceLower cost than precious metal alloys
Maraging Steel MS1
“Maraging” is a combination of the words martensitic and aging. Martenistic refers to the rapid cooling (or quenching) of the elements upon combination. Aging refers to the extended heat treatment the alloy undergoes after being mixed. Maraging Steel MS1 contains mostly nickel with other elements – including cobalt, molybdenum, titanium, aluminum, and niobium – added according to required properties. The alloy is used to produce high performance parts for the aerospace industry. Important properties include: High strengthHigh hardnessEasily machinableAge hardenable up to 54 HRC (“HR” refers to the Rockwell hardness scale while the “C” refers to the load being used)Good thermal conductivityGood polishability
Nickel Alloy IN625
Nickel Alloy IN625 (often referred to by the trade name Inconel 625) is composed primarily of nickel, chromium, iron, molybdenum and various other elements in trace amounts. Nickel alloy IN625 is used to produce parts for the aerospace, motor sport, maritime, and chemical industry. Important properties include: High tensile strengthHigh creep and rupture resistanceHigh corrosion resistanceHigh temperature resistance
Nickel Alloy IN718
Like its cousin IN625, nickel alloy IN718 is composed primarily of nickel and chromium with other elements such as molybdenum, niobium, cobalt, and iron included in various amounts. Nickel alloy IN718 has properties that make it useful in high-stress applications such as turbines, rocket components, and chemical/natural resource industry parts. Nickel alloy IN718 also exhibits properties that make it potentially useful in cryogenic applications. Important properties include: High corrosion resistanceVery high tensile strength up to 700 CFatigue, creep, and rupture resistance up to 700 CCryogenic (low-temperature) properties
Stainless Steel GP1
Stainless steel GP1 is a trade name for the alloy that corresponds to 17-4 PH stainless steel (the “PH” stands for Precipitation Hardened and the “17-4” refers respectively to the percentage of chromium and nickel added to the alloy) prized in engineering applications because of its mechanical properties (ability to be molded) and ductility. Important properties include: Excellent ductilityGood mechanical propertiesHigh strengthCorrosion resistance
Stainless Steel PH1
Much like stainless steel GP1, stainless steel PH1 is a trade name for the alloy that corresponds to 15-5 PH stainless steel used in many engineering and medical applications including functional prototypes, small-series products, spare parts, and any part that requires high strength and hardness. Important properties include: Excellent mechanical propertiesVery high strengthEasily hardenable up to 45 HRCHigh hardness
Titanium alloy Ti64 (a.k.a. Ti6Al4V or Ti-6Al-4V) is composed of titanium, aluminum, vanadium, and iron (the “6” and “4” refer respectively to the percent of aluminum and vanadium included in the alloy). Titanium Ti64 has been put to wide use in the aerospace and biomedical industry. Important properties include: Low weightHigh strengthBiocompatibility with very good bioadhesion (cell growth)Corrosion resistanceExcellent mechanical properties
Open Hardware 3D Printing Iniatives
PWDR was conceived and executed by Alex Budding while enrolled as a mechanical engineering student at the University of Twente in Singapore. Budding saw the need for a powder-based, open-source 3D printer and set about making it a reality. When the original 3D printer prototype was completed, Budding released his designs and specifications for the DIY enthusiast to use and build on. Information for building the PWDR model 0.1 can be found at www.pwdr.github.io.
Current The PWDR printer translates CAD design information into instructions that guide the print head to produce a specific shape from the raw material. Like all additive manufacturing, PWDR builds 3-dimensional objects from the ground up. According to Budding, PWDR works like an ordinary desktop printer save for two important features: The print head works in three dimensions rather two. The printer “prints” onto a layer of white gypsum rather than paper. The process begins when an inkjet deposits a liquid binder mixed with ink onto the aforementioned gypsum powder. When the first layer is done and the print head has passed, a roller bar drags a thin layer of powder across the surface of the already-printed layer and the process repeats until the object is fully formed. When the print process is complete, the part must harden for a couple of hours, then be gently cleaned with a brush and “fixed” with cyanoacrylate (a clear glue that strengthens the bonds between the print material). Future PWDR, though currently set up for powder-based printing, can theoretically be altered (with the substitution of a laser head) to perform selective laser sintering (SLS).
In its current iteration, PWDR can theoretically make use of any light-weight, powdered material such as gypsum, ceramic, concrete, sugar, and others. Should an SLS process be developed through open-sourcing, PWDR could take advantage of an expanded array of building materials such as acrylonitrile butadiene styrene (ABS), polypropylene (PP), Nylon, and even metals.
Though PWDR is fairly rudimentary compared with commercial additive manufacturing processes (DMLS, EBF3, SLA, etc.), it is an affordable technology that fills the powder-based, DIY 3D-printer niche. The printer can be constructed in a matter of hours for around $1500.00 (U.S.) using off-the-shelf components. As an open-source project, PWDR has the potential to provide many benefits not yet conceived. Budding speculates on the possibility of multicolor printing, incorporating SLS (as mentioned above), making use of new materials, and designing new print algorithms.Images CC Universiy of Twente