While the jury is still out on 3D printing for the consumer market, there’s little question that it’s becoming a major part of next generation manufacturing. While we often think of 3D printing as a way to create highly customized one-off objects, that’s a conclusion largely based on how we as individuals use the technology. When you’re building something as complex as a rocket engine, the true advantage of 3D printing is the ability to not only rapidly iterate your design, but to produce objects with internal geometries that would be difficult if not impossible to create with traditional tooling.
So it’s no wonder that key “New Space” players like SpaceX and Blue Origin make use of 3D printed components in their vehicles. Even NASA has been dipping their proverbial toe in the additive manufacturing waters, testing printed parts for the Space Launch System’s RS-25 engine. It would be safe to say that from this point forward, most of our exploits off of the planet’s surface will involve additive manufacturing in some capacity.
But one of the latest players to enter the commercial spaceflight industry, Relativity Space, thinks we can take the concept even farther. Not content to just 3D print rocket components, founders Tim Ellis and Jordan Noone believe the entire rocket can be printed. Minus electrical components and a few parts which operate in extremely high stress environments such as inside the pump turbines, Relativity Space claims up to 95% of their rocket could eventually be produced with additive manufacturing.
If you think 3D printing a rocket sounds implausible, you aren’t alone. It’s a bold claim, so far the aerospace industry has only managed to print relatively small rocket engines; so printing an entire vehicle would be an exceptionally large leap in capability. But with talent pulled from major aerospace players, a recently inked deal for a 20 year lease on a test site at NASA’s Stennis Space Center, and access to the world’s largest metal 3D printer, they’re certainly going all in on the idea. Let’s take a look at what they’ve got planned.
Last week I went to the International Manufacturing Technology Show (IMTS) and it was incredible. This is a toy store for machinists and showcases the best of industrial automation. But one of the coolest trends I found at the show are all the techniques used to 3D print in metal. The best part is that many of the huge machines on display are actually running!
It’s probably better to refer to this as additive manufacturing, because the actual methods can be significantly different from your 3D printer. Below you’ll find examples of three different approaches to this process. I had a great interview with a company doing actual 3D printing in metal using a nozzle-based delivery often called cladding. There’s a demo video of powder layer printing using lasers. And a technique that uses binders as an intermediary step toward the final metal part. Let’s take a look!
Formlabs have just announced the Fuse 1 — a selective laser sintering (SLS) 3D printer that creates parts out of nylon. Formlabs is best known for their Form series of resin-based SLA 3D printers, and this represents a very different direction.
SLS printers, which use a laser to sinter together models out of a powder-based material, are not new but have so far remained the domain of Serious Commercial Use. To our knowledge, this is the first time an actual SLS printer is being made available to the prosumer market. At just under 10k USD it’s definitely the upper end of the prosumer market, but it’s certainly cheaper than the alternatives.
The announcement is pretty light on details, but they are reserving units for a $1000 deposit. A few things we can throw in about the benefits of SLS: it’s powder which is nicer to clean up than resin printers, and parts should not require any kind of curing. The process also requires no support material as the uncured powder will support any layers being cured above it. The Fuse 1’s build chamber is 165 x 165 x 320 mm, and can be packed full of parts to make full use of the volume.
In the past we saw a detailed teardown of the Form 2 which revealed excellent workmanship and attention to detail. Let’s hope the same remains true of Formlabs’ newest offering.
We are all used to Fused Deposition Modeling, or FDM, 3D printers. A nozzle squirts molten material under the control of a computer to make 3D objects. And even if they’re usually rather expensive we’re used to seeing printers that use Stereolithography (SLA), in which a light-catalysed liquid monomer is exposed layer-by layer to allow a 3D object to be drawn out. The real objects of desire though are unlikely to grace the average hackspace. Selective Laser Sintering 3D printers use a laser on a bed of powder to solidify a 3D object layer by layer.
While an SLS printer may be a little beyond most budgets, it turns out that it’s not impossible to experiment with the technology. [William Osman] has an 80 W laser cutter, and he’s been experimenting with it sintering beach sand to create 2D objects. His write-up gives a basic introduction to glassmaking and shows the difference between using sand alone, and using sodium carbonate to reduce the melting point. He produces a few brittle barely sintered tests without it, then an array of shapes including a Flying Spaghetti Monster with it.
The results are more decorative than useful at the moment, however it is entirely possible that the technique could be refined. After all, this is beach sand rather than a carefully selected material, and it is quite possible that a finer and more uniform sand could give better results. He says that he’ll be investigating its use for 3D work in the future.
We’ve put his video of the whole process below the break, complete with worrying faults in home-made laser wiring. It’s worth a watch.
Filament printers are here to stay, and in the past year there have been a number of SLA and DLP resin printers that can create objects at mind-boggling high resolutions. Both of these technologies have their place, but printing really complex objects without also printing supports is out of the question.
[Brandon] has been working to create an open source printer using a different technology, selective laser sintering. That’s a laser melting tiny particles of stuff to create an object. This printer can work with any material that can be turned into a powder and melted by a laser, and also has the neat bonus of printing without any supports.
[Brandon]’s printer, Ester, uses small meltable polyester dust as both a print material and support structure. The object to be printed is created by shining a laser over a bed filled with polyester, drawing one layer, and putting another small layer of material over the previous layer.
The machine is using a diode laser, with a few experiments with a 1 Watt diode providing some very nice parts. The mechanics of the machine were built at [Brandon]’s local TechShop, and already he has an IndieGoGo for future development and a $3000 development kit. That’s a bit expensive as far as project printers go, but SLS is an expensive technology to get right; ‘pro’ SLS printers are in the hundreds of thousands of dollars.
We’re not sure how we missed this one, but it definitely deserves a look. Professor of Mechtronics [Olaf Diegel’s] 3D printer must go to 12, because he’s printed these incredible electric guitar bodies. You probably won’t be making your own on your filament printer, however, because [Diegel] uses SLS (Selective Laser Sintering) to create the body out of nylon, then he dyes the resulting piece in a two-step process. You can read more about the construction specifics on his website.
And, they’re more than just eye-candy: the guitars sound brilliantly metallic. There are more than enough pictures and videos to keep you occupied on the site, where you can sift through all eight designs to your heart’s content. You’ll want to keep reading for a couple of videos embedded after the break, which feature some demonstrations of the guitar and comparisons to traditional electric guitars, as well as a brief history of its construction and build process.
Most any rocket engine you’d find on a spacecraft – save for solid or hybrid rockets – use an engine system that’s fairly complex. Because of the intense heat, the fuel is circulated around the chamber before ignition giving a motor its regeneratively cooled nomenclature. This arrangement leads to a few complicated welding and machining processes, but surprisingly these obstacles can be overcome by simply printing a rocket engine on a 3D printer.
The current engine is quite small, but still fueled just like any other proper rocket engine that makes it into Earth orbit. The fuel is propane, the oxidizer is NO2, and the entire device is ignited with an automotive spark plug. Of course this was an expensive proposition; a motor with 12 pounds of thrust cost somewhere in the range of four figures.
Printing a rocket engine has a few advantages over traditional manufacturing techniques. [Rocket Moonlighting] explains that traditional techniques (mills, lathes and other heavy equipment) are bound by labor, material, and time. The costs of printing a rocket engine are only bound by the volume of the finished piece, meaning the most expensive engine per unit of thrust is the one that will fit in your pocket; scaling up means more efficiency for less cost.
There are a few videos up after the break showing the engine in action at full throttle, a few start and restart tests, and a test that involved throttling the engine. It’s an extremely impressive piece of kit, and hopefully [Rocket Moonlighting] will release the CAD source so we can make our own.
EDIT: [RM] tells me his engine cost less than $2000 to make. If just 10 people wanted their own engine from a ‘group buy,’ the price would drop by more than half. If you’d like your own 3D printed rocket engine, you might do well to drop [Rocket Moonlighting] a line.