I am looking for info on Direct Metal 3D printer

[richardphat]

Do tell me more about when it burnt the grinder, for the sake of a pyroman!

[Marm]

Like I said, I was deburring the edges of 3" tubes, about 5' long, using a flapper wheel (sandpaper basically) that was on a grinder. It was the type of grinder that had exhaust ports to be hooked upto a suction unit to be collected in a 50 gallon drum, except we didn't hook it up because we didn't want 50 gallons of dust right behind a spark machine. So, with the guards and circular housing of the grinder, the flapper wheel was basically a centrifugal pump, but with air. There was a small pile of dust on the bottom of the housing that we'd clean out every so often, but most of the dust just blew out on to the floor, which we'd sweep up at the end of a shift. (Sounds like a problem, but there wasn't a lot of dust, trust me). Every now and then the wheel would throw a spark from the tube, and it'd spin around the housing a few times going weeeeeeee! and go out. Well, one time, it threw a bigger spark than normal, and it planted itself right into the pile of dust. With the wheel acting as a blower, it quickly ignited. Had about a 2-3' yellow white flame shooting the back of the grinder for a minute or so. Turned off the machine and as the wheel slowed, the fire went out. But the power cord had been laying just close enough to be melted by the flames.

[LarryC]

AL could be done with a MIG welder on a suitable gantry. I have seen SS done by a remote controlled TIG setup.

Are you looking to do Sintered metals or solid metals? For such a small physical work volume, unless the design precludes it, standard subtractive machining might be the better option.

[madmanmax]

LarryC, I need greater detail than could be achieved with a welder. my intention is to do things that would otherwise require casting.
The rest of you are all right about the flammability and explosive property of aluminum and titanium when oxygen is present.
Most printers for these materials use a sealed chamber filled with argon gas, therefor no oxygen and no fire potential.