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.
It’s always interesting to see what happens when hacking meets clothing – check out this pair of bikinis, for instance.
This first item, called the N12 bikini (mildly NSFW), comes from Continuum Fashion and is composed entirely from Nylon 12, hence the name. Shapeways uses 3D Selective Laser Sintering (SLS) to create the tiny circles that make up this piece of swimwear. The suit is held together by tiny stretchy strings made of the same nylon, and the bikini can be printed to order. It seems like an interesting idea, but we wonder how it would hold up against some big waves or a game of beach volleyball.
The second item is a bit more functional. Designer [Andrew Schneider] has put together a bikini that can solve all of your energy needs while sitting by the pool. His solar bikini is covered with hand-sewn flexible solar cells that work together to produce up to 5v, available via a USB connection. He claims that you are free to go swimming in the suit, so long as you dry out the USB port before using it again. For all the guys out there crying foul, don’t worry – he’s got a suit for you too. He’ll be putting together a men’s suit in the near future that powers a 1.5 amp Peltier cooler to keep your beer cold – we just don’t want to know where the hot side of the Peltier goes…