I've had a 3D printer since late last year, it's a great gadget and not all that expensive to buy and run.
It works by feeding a 1.75 mm filament of ABS plastic into a heated print head (needs 260deg to melt the plastic) and the melted plastic is forced through a small nozzle (about 0.25 mm diameter) and it simply squirts it out onto the table and builds up the object layer by layer, again about 0.2 mm thick at a time. So it's very slow and can take up to five or six hours to make a large-ish object. The limits for my machine are a cube about 130 mm to a side.
I bought it to prototype some golf tees that a friend of mine invented, they stop you hooking & slicing the ball. We figure there'd be about a hundred million golfers that'd want them.


