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3D ceramic printing.

Posted: Tue Aug 09, 2011 4:46 pm
by Chris Bradley
Mark Suppes has found a web-place to do some 3D printing of his polygrids, and it looks like there is a lot of potential from such a service! I figured it'd be worth pinning the link up on the forum here:

http://www.shapeways.com/materials/ceramics

Kudos to Mark for finding them.

I'm currently attempting to figure out how to mould fire cement into the shapes I need, which might be an effort made redundant by this service.

Re: 3D ceramic printing.

Posted: Wed Aug 10, 2011 12:17 am
by Rich Feldman
What's the guaranteed range of dimensional shrinkage during firing?
(e.g., "at least 15% but not more than 20%").

Re: 3D ceramic printing.

Posted: Wed Aug 10, 2011 2:13 am
by Chris Bradley
There are design-rules listed. I've not explored that yet.

Re: 3D ceramic printing.

Posted: Wed Aug 10, 2011 11:14 am
by Doug Coulter
The big problem with ceramics (I did some hobby pottery type stuff) is that in any 3d shape, there are issues with cracking during shrinking as that implies a surface area/volume change, so you have to control cross section variations or it will fly apart.

Why not just buy various ceramics, prefired, put them together with something, and use that? That's how I've been doing it.

Re: 3D ceramic printing.

Posted: Wed Aug 10, 2011 12:57 pm
by Todd Massure
The other option might be machinable ceramics like Macor, but I can't speak from experience about how they are to work with or how they perform.

Re: 3D ceramic printing.

Posted: Wed Aug 10, 2011 4:54 pm
by Chris Bradley
Doug Coulter wrote:
> Why not just buy various ceramics, prefired, put them together with something, and use that? That's how I've been doing it.

I have 'two left hands' and am pretty bad at 'crafty' stuff. There would be too much work making the specific shapes I need. I'm not very interested in learning a new 'trade' if I can afford a professional's price for doing it. I'm not trying to have fun learning how to build something, I'm trying to do a specific scientific experiment with a clear 'success' or 'fail' end point that I want to get to asap, to a budget. I guess that isn't most folks outlook, here, but I think it is for a few.

Re: 3D ceramic printing.

Posted: Wed Aug 10, 2011 5:17 pm
by Dustin

Re: 3D ceramic printing.

Posted: Wed Aug 10, 2011 6:08 pm
by Todd Massure
I messed around with that castable stuff from Cotronics, but it shrank a lot when it dried and I had problems with it cracking. What made me give up on it though was that I realized it was very porous and most likely terrible for any vacuum applications. It might be fine for creating custom insulators that aren't exposed to vacuum. I think it's a neat product, but it probably has limited applications.
Steve, did you have good luck using it in the past?

Todd

Re: 3D ceramic printing.

Posted: Wed Aug 10, 2011 8:00 pm
by Doug Coulter
I had the same experience with that stuff (kinda mentioned that above). And Chris and others know that while others were coaxing me to wait for good scrounge targets, I just bought a new vacuum system at brand new prices from Pfeiffer (actually, two of them and a mass spec on top). If he wants to pay extra over what it would cost to cobble something up, I have no ax to grind with the philosophy. But time-to-experiment to find out that perhaps ceramic isn't even the right approach would seem to be best just trying something quick (even if you do have two left hands) that may not be perfect, but might disabuse one of some error in thought about how it would perform in a particular application. If the simple/easy test works, then go for the expensive version, perhaps. Though anything that they can do in a 3d machine is almost guaranteed to not perform as well as fired alumina for "ceramic type jobs" as it would have to have a lot more binder in it.

I found this out the hard way making ceramic composite grids. While pure alumina can't be reduced to metal by hot H, the binders usually used can (clay type chemistry). So all the early experiments failed miserably, and I had to get the exotic, more expensive, pure stuff. Seems to me like betting on a single possibility (whatever those guys can work with) is hoping that this substance will work. If it fails, you've got no where to turn -- after having paid a premium for the attempt. That's all.

I'm left handed. It's the good one....

Re: 3D ceramic printing.

Posted: Wed Aug 10, 2011 8:07 pm
by Dustin
I have some, but have not had the opportunity to try it out yet.
Probably not good for a vacuum seal but may be ok for a vacuum insulator, having a porous surface it may take longer to become conductive if it gets sputtered (increased path length).
May also be good for shadowing expensive insulators.
Steve.

Re: 3D ceramic printing.

Posted: Wed Aug 10, 2011 10:11 pm
by Steven Sesselmann
Todd,

I have machined Macor, and apart from the cost, it actually works well. It was used in my Starfire Ion sources which were documented in the Ion Gun Design forum.

viewtopic.php?f=12&t=5013#p32321

Steven Sesselmann