There are also machines that assemble metal parts from powder by distributing powder and then using a laser to melt it, layer by layer: http://en.wikipedia.org/

There are also machines that assemble metal parts from powder by distributing powder and then using a laser to melt it, layer by layer: http://en.wikipedia.org/wiki/Selective_laser_sintering http://en.wikipedia.org/wiki/Selective_laser_sintering (If you used laser cutting, it seems it would be hard to make non-convex parts, since you can't stop the laser at a certain depth.)