There’s an interesting discussion underway at the RepRap forums, where the idea of Direct Metal Laser Sintering is being pondered. DMLS involves laser-heating metal (or other material) powder, layer by layer, slowly building up a solid object. This is pretty similar to how many 3D printers work, but the interesting bit is that these guys are contemplating designing a system that could do this at home:
In other words, it’s a laser cutter with a powder bed. This should be hackable by combining an off-the-shelf laser cutter with Fab@home or even CandyFab technology. From there it’s all about finding the right settings.
and:
It may be necessary to work under a nitrogen or carbon dioxide atmosphere, as steel powder is highly flammable under the right conditions
So it’s not quite as easy as it sounds, but we may soon see a MakerBot-like device that prints wrenches and hammers. Where’s our fire extinguisher again?
Via Open Manufacturing and RepRap Forums (Hat tip to Micah)
I'm guessing the conditions would be similar to those of arc welding, the molten steel will oxidise quickly when molten forming a rusty dust which will then contaminate the rest of the metal and have undesirable effects such as bubbles.
Carbon Dioxide is not inert at these temperatures, it's actually added to welding gasses to increase temperature.
Argon would be the best gas to suppress oxidation in the metal. It can be bought in small canisters from most DIY stores and in larger ones from welding suppliers.
Another thought would be to attach a MIG (GMAW) welder to the end of your Reprap and use that for building up a model.
Cheers,
Andy
Steel printing was done on the Model 1 Fab@Home two years ago by Maxim Lobovsky at Cornell University. It required post processing, but the shape was made at safe temperatures for a home environment
http://www.mae.cornell.edu/ccsl/papers/SFF08_Lobovsky.pdf