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Old Yesterday, 08:49 PM
Veni, Vidi, Feci
patmat2350's Avatar
Motor City
Joined Dec 2004
12,052 Posts
Sometimes the truth hurts.
Sometimes a soft focus is a good thing.

But here is the hurtful truth in sharp focus-- 3D printed parts are rough!

Here is some of my 3DP anchor chain under the microscope. The parts are as-delivered from Shapeways (plus a little of my lint). They've been washed but not real well; parts should be washed again to remove the last of the support wax before being painted.

But you can see the jaggies and layering... and these parts are made at Shapeways' best resolution in their "frosted ultra detail" acrylic.

But really, with the naked eye, you see none of this. It does cause me some extra work, as those jaggies can stick to one another in my smallest chain, and I have to work EACH link by hand to ensure they're free.

The smaller chain here is printed with 0.5mm (0.020") "wire diameter"... smaller than the wire in most sewing pins!


.
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Last edited by patmat2350; Yesterday at 10:08 PM.
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Old Today, 07:09 AM
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Jerome Morris's Avatar
Union, Maine
Joined Jul 2006
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Ooooo. Those look horrible.
More work cleaning them up than I realized.
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Old Today, 07:40 AM
Registered User
United States, ID, Rexburg
Joined Sep 2008
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just to ask a question what would happen if you put them in a tumbler full of fine sand (like people use for polishing brass shell cases.....
Foo
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Old Today, 08:24 AM
Veni, Vidi, Feci
patmat2350's Avatar
Motor City
Joined Dec 2004
12,052 Posts
Quote:
Originally Posted by Jerome Morris View Post
Ooooo. Those look horrible.
More work cleaning them up than I realized.
But as shown above Jerome, this is at a level you can't even see without a magnification. A baby's behind would look pretty gnarly too under a microscope.

Foo- tumbling has been used for larger robust parts... but I'm tempted to find a suitable medium for this delicate stuff and try it out. I have a rock tumbler just waiting for the experiment...

But again, this may be a solution for a non-existent problem... the chain looks fine to the naked eye!
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Old Today, 11:03 AM
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deckert's Avatar
USA, WA, Benton City
Joined Oct 2007
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I'd try a vibratory tumbler with walnut shell media as the abrasive. My parts from Shapeways aren't real smooth either. I should have them printed with an Objet Printer but then the costs go way up. Big difference between .2mm & .003mm. The $250 setup fee for high res prints stopped me..


Dan
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Old Today, 12:12 PM
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United States, ID, Rexburg
Joined Sep 2008
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I would think that if you could find a fine enough abrasive it would do pretty well even for the very fine imperfections you are talking about. Walnut, or even black magic (carborundum) is probably way too coarse and aggressive for taking the little stuff off your chains.
Foo
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Old Today, 12:54 PM
Veni, Vidi, Feci
patmat2350's Avatar
Motor City
Joined Dec 2004
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I believe these parts are printed on a 3D Systems Projet 3500 HD. The specs on the machine’s high def mode (used with Frosted Ultra Detail) appear to align with what I see under the microscope:

XY (plan view) precision: 375 dots per inch, or 0.068 mm per dot = 68 microns per dot… or ~ 7 “dots” across my 1/2mm chain “wire”.

Z (vertical) precision: 790 DPI = 0.032mm per dot = 32 micron layer thickness, or 16 layers for my 1/2mm chain wire.


Now, we were all amazed when HP came out with 300 DPI print capability in the Laserjet 4… you simply could no longer see the “jaggies” in printed line art. So even though these parts look rough under a microscope, they’re actually pretty darn good!
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