i need help for 3d sand printer
May 05, 2011 03:18PM
i work on 3d sand printer but there is one big problem .
this problem is separating sand with thickness .1 mm to make sand molds
i ask if any one can send to me idea to help me , i work on my graduation project
VDX
Re: i need help for 3d sand printer
May 05, 2011 03:30PM
Hi designer,

i've separated glass spheres with a nominal diameter of 0.2mm, but a real distribution between 0.005 and 0.7mm (even found some with >1mm diameter) and broken ones in different sizes by sieving through meshes with specific sizes.

Found some woven plastic meshes and etched nickel foils with through-holes of 0.03, 0.05, 0.1 and 0.2mm, so started with the biggest and separated the glass spheres in >0.2mm, 0.2mm to 0.1mm, and so on until <0.03mm.

Should work with sand too, but you won't have the same fine distribution as with spheres ...


Viktor
--------
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Call for the project "garbage-free seas" - [reprap.org]
Re: i need help for 3d sand printer
May 05, 2011 03:39PM
thnx VDX

but i ask about mechanism and method which separate sand , if you can give me sketch or pic . please
VDX
Re: i need help for 3d sand printer
May 05, 2011 06:43PM
... i simply made some boxes with pieces of the meshes as bottom, then poured a portion of the spheres in the box with the coarsest mesh and sieved the smaller spheres in a dish - then sieved the smaller spheres from the dish through the next finer mesh and got the 'medium' fraction in the second box with the bigger spheres in the first box and all the smaller ones in the dish ... and so on ...


Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]
Re: i need help for 3d sand printer
May 06, 2011 03:35AM
"Figure 4.3, Dry Sieve Analysis"
http://www.geology.sdsu.edu/classes/geol552/seddescription.htm

This may be helpful as well:
http://en.wikipedia.org/wiki/Mesh_%28scale%29

Viktor, I have a stupid question:
Do the gold-plated metal meshes filters used for coffee have about the right hole size to be useful?
http://www.amazon.com/Cuisinart-GTF-Gold-Tone-Filter/dp/B0001IRRLG

(They are much less expensive than filters intended for industrial and scientific applications.)


designer, are you building a machine like
http://reprap.org/wiki/AdderFab?

Would you like to upload some drawings and sketches to the wiki?
Re: i need help for 3d sand printer
May 06, 2011 03:55AM
Also, I think you're asking about how to deposit a precise layer of sand, not how to sort a bag of sand into various size particles, correct? grinning smiley


-Sebastien, RepRap.org library gnome.

Remember, you're all RepRap developers (once you've joined the super-secret developer mailing list), and the wiki, RepRap.org, [reprap.org] is for everyone and everything! grinning smiley
VDX
Re: i need help for 3d sand printer
May 06, 2011 03:58AM
Hi Sebastien,

... 'coffee-filters' could be usefull for really fine powder - my applications mostly needs sizes around 0.03, 0.05 and 0.1mm.

With finer granulities the powders (mostly plastics, but sometimes glass too) are much more 'sticky' and will adhere more to the rolls and blades ...


Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]
Re: i need help for 3d sand printer
May 06, 2011 05:50PM
Just reread the initial post, .1 is very fine, so the stuff below does not apply.


I think a machine called prometal builds moulds, good resolution,
Afs 80 silica sand for foundry work, at about .6mm should spread, you could add honite glass blast media at around 10% by weight to help flow. Hopper or feed bin are the common methods employed.

What methods have you considered, and what binder are you using.

Edited 1 time(s). Last edit at 05/06/2011 05:57PM by johnrpm.


Random Precision
Re: i need help for 3d sand printer
January 06, 2012 11:04AM
Hi there, how is it going with this sand printing ?

I'm thinking about building a riprap to print climbing grips which are basicly made out of polyester with sand so if this can be printed it would be realy cool
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