I have been intrigued by these 3D printers, and amused to watch them start making not just high capacity magazines, but even an AR-15 lower receiver that held together for more than 600 rounds. A friend in Nevada tells me that he is beginning to see these receivers, and even complete AR-15s built on them, at gun shows.
My business interest is a bit less scary to the left: instead of making the parts for ScopeRoller that I make now from aluminum, perhaps I could make them out of the ABS plastic as the AR-15 lower receiver? Instead of the multiple steps that I now use (cutting aluminum tube to size, cutting a piece of acetal, drilling and tapping the acetal piece, drilling holes and putting it all together) I could print a single assembly, then tap the four holes required in each piece?
Advantages include: I can make a part that is exactly what I need (which means a single unit); less waste, because I won't have any scrap left over after manufacturing; far less labor, because I can have the machine make exactly what I need while I am doing other things.
Disadvantages: I suspect that the materials cost will be higher than aluminum (although probably not much higher than the part that I make out of acetal); I need to make a capital investment of about $1600 in such a machine; I have to figure out how to describe the shape of the object in STL format. I suppose the next step is to find a vendor with one of these machines so that I can see how fast they work, and how solid the ABS output is.
UPDATE: It looks like ABS would not be a good choice, because it is brittle, and tapped holes are not likely to last. Nylon might be a better choice, but it is somewhat flexible, so I would need to make some of these parts thicker and larger. And the plastic raw material is expensive -- like $79 per kilogram from one vendor, $54.50 per kilogram from another. Perhaps I should look at upgrading my vertical mill to CNC instead, and have the robot machine stuff out of a block of aluminum. That's less capital-intensive than the various 3D printers, and the materials costs are far lower. There's still the learning curve, however.
Here's a vendor that sells a small 3D printer for $899. It seems to be limited to 120mm x 120mm x 120mm -- just a little small for some of the items that I ship.