Amazing technology of 3D printers suggests hugely flexible ability to produce parts and gear of all kinds. Have these printers got a role in survival planning?

[3D plastic, food, and metal printing exist.]

I can see how they can be usefull, but for now the are pretty expensive, complex and slow.

If they can make it as easy as inserting a catridge, download a 3D parts file and click on start and have your part ready in 5 minutes...

Yep. And getting cheaper and easier all the time.

Should we keep this technology on survival prep radar?

[Especially with growing ability to feed the machines with found plastic stuff, organic material, etc.]

The thoughtful person will equip with versatile, basic gear (That is why ETS!), but most important is the ability to innovate, adapt, and improvise - "think outside the box." Maybe a 3D printer can give us the box outside of which we can roam...

I believe so. It's no different than a drill press, a lathe, or a milling machine (which is the closest sibling of 3D printers, by the way), it's just using different "blanks". The prep/survival value of the later tools is obvious. The learning curve for all of them is quite comparable. My tabletop 3D printer is of a rather inexpensive class ($500 kick-started) but it's not far from your goal (load it in the evening, - pick-up the fresh new item in the morning). See my thread here: http://forums.equipped.org/ubbthreads.php?ubb=showflat&Main=19447&Number=279494 The only "unpleasant" issue to me is that when I change the plastic type, I have to go through its initial testing, trial and error phases again, so precise documenting of your 3D printing efforts is essential for repeatability of the result. Also I'm aware that if I switch to another printer model, I will have to rerun all my plastics again - that's usually not the case with a lathe or drill press, but I consider it just a minor inconvenience, actually.

If I could pay 3-4 times more I could opt for a more expensive, brand model of the printer, which provides the special plastic filament as well (also more expensive), so you need just dial in its vendor code and have the printer process optimized automatically to use it flawlessly.

For serious lathe or even drill press projects it's still good to have some practical CAD knowledge (actually, even more so than for 3D printing, as you cannot just download a model for lathe and have it turned in metal to you specs, though millions of parameterisable models already available for 3D printers), unless you plan to produce just cylinders with the hole in the middle