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Coarse infill below 25%

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Tested with Cura 13.06.4 and 13.07.T2.

Infill settings below 25% produce a very coarse structure.

25%:

InFill25

24%:

InFill24

The infill created with 24% looks more like a 10% setting.

Is there any quick workaround available?

Any command line arg for the slicer that can be enabled/changed to

revoke an older algorithm?

 

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Above 25% Cura does infill lines in only 1 direction per layer.

Below 25% Cura does infill lines in both directions in each layer, making stable squares.

So below 25% it does put in 25% infill, but because it's doing lines on both directions the distance between the lines is bigger then with above 25%.

 

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Hi,

 

I’m one of the exited Ultimaker² buyers. I am following the development of Ultimaker for quite a while and always thought, once I would by a 3D printer it should be an Ultimaker. I really love their philosophy.

 

I have two questions related to infill:

 

  1. Wouldn’t it be good to use a kind of http://en.wikipedia.org/wiki/Bitruncated_cubic_honeycomb as infill? Structurewise it should be one of the strongest solutions in relation to the material used.
  2. Did anybody realised cracks in there hollow structures based on barometric pressure changes during air travel, in the mountains or on their model aircraft build out of 3D printed components?

I’m looking forward to become a part of your amazing community.

 

Ion

 

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cubic honeycomb. Smart. Yes - of course this would be stronger.

PLA is very strong. Many people never do any infill at all. printing takes a loooong time. Your prints may take 5 to 20 hours typically. Anything that saves time is welcome. So straight lines are much faster. The earlier Cura did several infill types including standard honeycomb but it prints much slower (3X maybe?). The current Cura only has the 2 types of infill (one lower than 25%, the other above 25%).

Think Legos. They don't need any infill at all - they are hollow and have no honeycomb structure anywhere. Legos are made of ABS. PLA is similarly strong - I suspect ABS is stronger but I don't know.

 

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With most shapes you're going to get the most structural benefit from just thickening your walls instead of changing your infill pattern. Additionally, infill doesn't really contribute as much strength as it could - not because of its shape directly, but because often those thin, intersecting interior walls don't have as great of layer adhesion as the thicker outer skins.

Like gr5 suggested, I very rarely print with infill, because I find it faster, stronger, and more reliable to simply print with thick walls (2-4mm).

 

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But leaving out infill is often a problem for models with a flat top. Cura is smart and starts to add infill for itself when it approaches the top, but on many models (mostly humanoid heads) it would fail misserably without infill. I whish it would be possible to print with "variable infill" where one can somehow specify the infill amount for the z-height.

@gr5: Great idea bout variable speed. I'd love to use that too. I don't care about the quality of infill - this can be printed pretty fast. But what would you do about temperature? If you print at say 50mm/s and would want to have 300mm/s infill, depending on the layer height this is pretty impossible without change temperature (or flow rate which handles the rest I guess).

 

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Well I was thinking when the layer height is .06mm or thinner this would be helpful. And maybe the top speed would be only 200mm/sec. But I suppose for .2mm layer height you would have to print at 240C.

 

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Hi Daid

 

Is it possible in the upcoming versions fo Cura again to implement different infill types, even if they are slower?

 

I didn’t get an reply on my second question. I am really wondering about the effects of air pressure on hollow and air tight structures. Is there experience on that? Even though water pressure might be the better example. I have seen some GoPro Scuba Mask Mounts on Thingiverse. I’m wondering, if they might break based on their hollow infill.

 

Greetings,

Ion

 

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