I'm not really sure what relation the article's headline has to its content - apart from the obvious problem that current 3D printing technology is nowhere near accurate enough for the tolerances involved in a jet engine, I don't think it will ever be possible to print one entirely, as the fan blades are each a single crystal of metal, and that's not a property you can achieve through any 3D printing method (or any incremental building method - they need to be created in one piece)
So they're making net-near-shape parts in lieu of castings so they can: 1.) get different part properties (lattice structures), 2.) so they don't waste very expensive materials that are often blocks of unobtainium with 95% machined away...
You're right - it's going to be very difficult to get high tolerance parts using any method of 3D Printing. Don't say never - but isn't not as close of the koolaid machine would have you believe.
You can manipulate individual atoms with lasers, and 'cool' them down to nearly absolute zero. So I wonder how far we are from being able to grow a single crystal part via laser sintering?
A very very long time. Laser sintering does not typically work on the per-atom level (those are called laser tweezers iirc), it works on relatively bulky material (powder or grains).
The result is definitely not crystalline, in fact it is better compared with regular sintered materials.
They are most likely printing things that 1) don't move, and 2) aren't subjected to any type of stress or heat.
I can't imagine that you can print something layer by layer with fused powder and expect to make anything as solid and tolerant as the normal (crystal) growth and/or casting/molding/etc processes make.
NASA is set to launch in 2017 a rocket stage that was in part '3D printed' via a form of laser sintering. [1]
Additionally, many aerospace parts (F22 air vents, for example) are produced in a similar fashion. There are a series of Google Tech Talks on the subject [2]. In short, complicated shapes can be produced with less waste (versus milling from a larger block of material), greater tolerances (no warpage from welding heat, curing of glue), less labor (no assembly jigs), and usually less mass (due to partial infilling of material cross section).
Lastly, you'd be surprised at the number of molds that are now being made via '3d printing' (I'm growing to hate this term) for composite applications. Normally they are CNC'd from aluminum (or 'tooling gel') - whereas smaller run items can be laser sintered. My startup uses PLA molds for vacuum infused carbon composites which we print from a RepRap Mendelmax. (router enclosures, antenna mounts, UAV and motosports stuff, etc).
Fan blades are definitely not all 'single crystals of metal', though that is one method of manufacturing them.
Usually they are simply cast and then reworked, which produces a blade of lesser quality than the single crystal ones but they are still quite usable (and a lot cheaper!).
The newer fighter engines (F414, F119, F135) use a single piece "Blisk" fan and compressor, although I don't think its 'single crystal'. For prototyping, they can be 3D printed but are usually cast from molds and balanced for the actual engine.
Computer guys are so cute, what with their naivety about the speed of progress in non-computer engineering fields. The article might as well be about terraforming Mars.
If you read comments to the post, the proposed solutions are:
self-healing film for tiny holes; baloons that move with the air flow and plug the holes with their bodies for medium holes; and evacuation to a safe place for a huge holes once in a century. It is a Russian blog so most ideas reside not in the article but down in comments :)
To be fair, if we get a good handle on available resources once we're there, the likelihood that we can send a 3d-printer to Mars that will build a living base is quite high. The assemble-in-place science can be made to work, and I believe we will be sending fleets of 3d printers to Mars, in the first wave of colonization, anyway ..
While the title is clearly suggesting that an entire jet engine is to be printed. The details of this application as stated in the article point to the specific method of laser sintering, which as a form of 3D printing, is useful to creating specific parts.
This article does illustrate the different methods of 3D or additive printing capabilities, outside of the common knowledge we seem to be exposed to through the maker movement. NASA / Military has also explored a multitude of options with additive printing, battle field printing and space station printing.
In regards to parts such as fan blades, which are mainly composite materials in recent engines, this would not be applicable. Where there are parts that are subject to extreme heat and must retain certain properties, therefore, expensive to manufacture, this process has many benefits as highlighted.
EDIT:
In the case of "extreme heat", it may apply for certain types of metals.
In regards to parts such as turbine blades(parts subjected to extreme heats and pressures), which are usually made of single crystal nickel-based superalloys, this would also NOT be applicable. That is until 3D printers have the resolution to print atom by atom....
I'm already 3d-printing most parts of the RC foamies that I need (except .. the foam materials itself), so .. props, control-surface elements (horns), motor-mounts, etc. So, its at least happening ("sudo 3dprint airplane") on the micro- level.
It will scale, eventually. I guess as soon as someone gets serious about the reproducible nano-compositor/decompositor style of printnozzle..
I don't, but you can see lots of great RC stuff on http://thingiverse.com/ as well as in the forums of http://rcgroups.com/ where there are a great deal of hobbyist builders pressing these new techs - as always - into serious use.
