Need some guidance

So I am really interested in getting into 3D printing. I would like to use it to manufacture limited quantities of hard to find parts. I even had Konica Minolta 3D laser scan some of those parts.
I have been researching as much as I can, but some advice from some veterans in this would be helpful. On thing I am looking to make is fuel cells, and plastic fairings, like the ones made of polypropylene. The fuel cell is a pretty decent size, say 20" across. I am also interested in printing much larger projects say up to 36"x36". So 2 questions, are there any DIY printers capable of printing fuel cells, and are there any larger printers?
So far the only process I could find to print a fuel cell is a commercially available EOS laser sintering machine.
Thanks, Anthony

The current DIY machines are currently limited to 20cmx20cm or 8"x8" Height varies also. from 10cm to 20cm on average with some much taller machines available.

There are experiments into larger printing machines, but nothing , that I know of, fully tested and documented yet.

Others?

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Komb'
Glankonian Protoforms

It is great to be excited, but i think you would be better off going and purchasing a print from shapeways. this will allow you to even know if the material choices available currently work for you.

Edited 1 time(s). Last edit at 03/01/2013 11:40PM by jamesdanielv.

I am currently in contact with a company that prints fuel cells for military drones with an EOS laser sintering printer. I believe the material is nylon and then they gold seal it. Just was curious if something like that machine was available for us DIY people. I've had little luck in getting EOS to call me back, as I would be interested in purchasing a machine.
Not sure if shapeways can print in the same material or not.
thanks for the info.

I haven't seen anyone attempt to print a plastic fuel cell before. I'm not sure if a desktop 3D printer has the tolerance to print a scaled down version. What feature sized and tolerances do you need to make a fuel cell?

20"x10"x20"H, not sure the tolerances, but there will be threaded holes incorporated, so probably down to the thousandths of an inch.

What are the problems associated with doing larger work?

that seems rather precise, do you have detailed specs or a web site I can go to to look at the details?

From what I know of modern fuel cells, the tolerances required are probably too tight for what a FDM printer can handle. An SLS printer should be able to do it, but it will depend a lot on the quality of the motors, drive method, and medium. Getting hardware that is sufficiently accurate will not be a trivial cost.

Are the motors like the ones used in cnc machines? I wouldn't mind spending 2-3 thousand building a machine that could handle this.

depends on if you mean hobby cnc, hobby cnc use steppers and an open loop system. we do the same for reprap. we home and assume the step count to be correct. over powerful steppers help ensure this is the case. if you want to read more about motors and systems concepts for reprap read here [en.wikipedia.org]

Ok, got it. Are there 3d printers that use servo motors instead?
Thanks for all the help!