We are beginning to 3D print metal parts now. But the fundamental problems remain, due to the nature of the 3D printing process. A 3D printer does sintering, applying successive layers of the material used, and heating it to fuse them.
Even with metal, you hit limitations in the kind of metal that can be used, and the heat required for fusing. (The heat requiresd may well make this a "Kids, don't try this at home" exercise.)
Conceptually, it's a bit like the difference betweem casting and forging iron. Cast iron simply isn't as strong as forged iron, and neither approaches steel. What if the part you want to make really needs to be made of steel?
A lot of things people might like to do with 3D printers are likely to remain the province of CNC milling machines, which sculpt the necessary part from an existing piece of metal that is hard enough for the intended usage.
Well, as to your second sentence. CAD drawings can be immediately converted to Numerical Controled Machine language which can operate many different machine tools. That's the easy part. But loading the stock, provisioning the machine with the appropriate cutters, etc. is considerable overhead for a one off item. Assuming a 3-D printer could process the same raw material (right now unlikely) a single or small production quantity might be less costly, overlooking completely the energy equation.
I'm not sure about structure strength. Crystalline structure is not much affected by proper machining and temperature control. It seems that would be hard act to follow for any type of deposition fabrication.
I also wonder about the ability to scale a 3-D printer. In most things one size doesn't fit all. I'll guess that both processes will be eventually be joined at the hip and both processes will be used to their best advantage.
Early users or investigators should never say never, but for a couple reasons I find 3-D printing limited. The primary limitation is that the printing process is an additive one where a maleable substance is deposited in precise locations. This is the opposite of most manufacturing processes in which material is precisely removed from a billet by various machining operations. The latter lends itself with few changes to an almost unlimited palet of materials from plastics to the hardest metals. I think power and speed must also be factored in somewhere. A lathe can remove a quarter of an inch of steel from a 4 inch long shaft in a matter of minutes, powered by a 1 HP motor. A 3-D printer would have to melt (assuming it possible) the amount of metal required to build the shape. Add to this the fact that most of the time heating the metal to melting point would drastically alter its characteristics.
I can see 3-D printers useful for building a T-Rex skull on the kitchen table and perhaps making paterns for castings but I'm not going to throw away my broom while waiting for a vacuum cleaner to appear in my paper tray.
"Specifically, GE is developing a metal nozzle for its LEAP jet engine. They will use 3D metal printers to produce the nozzles, which will be lighter in weight due to an advanced design producible only on 3D printers."
I agree 100 percent. The idea that 3D printing is going to displace a lot of the current manufacturing technology is misguided. But that said, I think we can all agree that it will be used for many applications and has tremendous potential. Plus, it's pretty cool too.
Thanks for the article Peter and I agree with your points, but thought I'd add this recent example.
Whether the average Joe can expect to buy the system AR uses is anyone's guess, but it already makes significant improvements in cost and schedule, so it will certainly stick around. Imagine what only a few generations of improvements to the system will do for reducing the system's cost and complexity.
These are all interesting points. 3-D printer is a bit of a mystery for me for long time.
For one, as one of my friends pointed out, it is very good to reproduce "one of a kind" thing. Think about an antique table that you just bought, but a leg is missing. 3-D printer would come in handy.
For another, I believe that it could work in a larger production scenario, too. I used to work for a consumer electronics company. I seem to recall that one of the big investments for those manufacturers was always in making a "mold" for their next product that needs to be mass produced. 3-D printer could take some pressure off of that mold cost.