Comment by Ellison Chan on March 8, 2012 at 2:43pm

They want to have 3mm minimum thickness on all printed parts!  Things are going to get heavy fast in stainless steel.

Checkout my 3D printed Firefly frame.  I just recently got all my parts, and got it off the ground.  Still need a little tuning, and I'll post a video.

Comment by ctech4285 on March 8, 2012 at 3:53pm

It should be printable. there 3mm rule only applies to thin long parts because in the 'green state' it is very brittle like uncured clay.
i will post some pictures as soon as i get them

Comment by Ellison Chan on March 8, 2012 at 4:13pm

They've been rejecting some of my other models lately, that have printed successfully before that were just under tolerance.  I think they do that when you print small parts that are part of other batches.  They don't want  to loose other orders if your's happens to break it.  

Take this one for instance:

For SWF, the wings tapered to 0.48mm at the tips.  Was printing fine, and even sold some before.  But they started rejecting all my orders, for tolerance.  I sold some batches where I put 4 of the models into one STL, and they passed that.   Probably because it was a big enough order to make one batch, with no other customer order mixed in.

I finally had to clip the wings by a few millimetres to avoid the tapering at the tip.

Developer Comment by R_Lefebvre on March 8, 2012 at 8:42pm

They can print stainless steel now?!?!

Comment by Ellison Chan on March 8, 2012 at 9:01pm

Yep, but it's very crude, with a resolution in the millimetres.  Their stated rule is 3mm wall thickness.  It's very crude.  Nowhere near the resolutions of the renderings above.

Comment by Todd Hill on March 9, 2012 at 8:18am

I watched their printing process from a link that Global Spec sent me some time back.  Pretty cool.  Has anyone done a cost benefit analysis of 3D metal printing to CNC machining, or metal casting?   

Developer Comment by R_Lefebvre on March 9, 2012 at 12:51pm

Ok, so it almost sounds like the output is similar to a sand casting, requiring finish machining at the end, which is not bad.  What's the physical properties like?  Is this a sintered powder metal process, or something else?

@Todd, I'd be curious about that too.  CNC can be incredibly cheap, however.  I'm shocked at how cheap some of the billet aluminum helicopter parts at Hobby King are.

Comment by Ellison Chan on March 9, 2012 at 3:25pm

Here's a video of the process:

Comment by Brad Hughey on March 12, 2012 at 9:11am

CNC is all about amortization of the overhead and setup costs over the production population (and so is printing or virtually anything in mass production).  I, too, have been flabbergasted at some of the stuff coming out of China and selling for a price akin to dirt.  I think the revolution in microfacturing is precisely due to the overhead and setup cost being continually driven ever lower so as to make small production runs of virtually anything economically feasible.

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