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xenomachina

Holes when printing included "voronoi heart" model

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I just tried printing the Voronoi heart model that was on the SD card included with my Ultimaker2. It seems to be this design, but I'm getting some noticeable flaws on the top surface of the inner heart. Instead of being flat, it has a bunch of holes and dimples.

 

How can I fix this problem? I assume it's caused by the still-molten plastic sagging. I've heard adding shells can help with this, but I assumed the files on the included SD should print fine without modification on a properly calibrated UM2.

 

This was printed with the default settings with the included filament (Ultimaker 2.85mm PLA "Ultimate Blue"). It's only the second thing I printed, after doing the initial setup (the first being the robot).

 

8TIglx4.jpg

 

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Depending on the model being printed and your layer thickness I usually have to increase the top/bottom to 0.8 - 1.00mm.

That said, if the bed temperature is a little high or the hotend temperature 230C or above then this issue is more frequent. If your filament allows it then try printing at 10C less and see if that makes a difference.

 

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Thanks. That guide looks extremely useful.

My fans were already set to 100%, so I tried reducing the temperature by 10C down to 200C (the default PLA temp seems to be 210C). I aborted this right away, as the print was not sticking to the bed at all. (Aside: how does one clean PLA off the outside of the nozzle? Or should I just not bother?)

I bumped it up to 205C, and this adhered well, and reduced, but did not eliminate, the pillowing.

Should I just not expect the included gcode file to print without flaws?

 

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Can you increase top/bottom thickness? Eventually it recovers and fills the hols in if you have enough layers. Usually .8mm is plenty but maybe you need more? Also using a layer thickness of about .2mm will probably fill in much better than .1mm. .1mm strands are more likely to tear. Also printing slower can help - say 25mm. So there's 3 things to try.

Slow helps because there is an acceleration and deceleration at the end of every line and there is a delay in building the pressure back up when starting the next line. This means the filament is slightly undrextruded as it starts out and can snap. Same issue is why .2mm is less likely to snap than .1mm or thinner.

 

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Can you increase top/bottom thickness? Eventually it recovers and fills the hols in if you have enough layers. Usually .8mm is plenty but maybe you need more? Also using a layer thickness of about .2mm will probably fill in much better than .1mm. .1mm strands are more likely to tear. Also printing slower can help - say 25mm. So there's 3 things to try.

Slow helps because there is an acceleration and deceleration at the end of every line and there is a delay in building the pressure back up when starting the next line. This means the filament is slightly undrextruded as it starts out and can snap. Same issue is why .2mm is less likely to snap than .1mm or thinner.

 

Can I assume that when you say "layer thickness" you are referring to the "Layer height" setting in the Quality section of Cura software?

 

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Hmm, I'm still getting "holes". It's not the bottom or top, but flat surfaces between the actual bottom and top of the print. Is there a setting for that? It looks like the bottom and top of my print is fine, no holes, but there are flat surfaces between the top and bottom that are quite hole ridden. Suggestions?

Here are my settings:

Layer height: 0.15

Shell thickness: 0.8

Bottom/Top thickness: 0.75

Fill Density: 20

Print Speed: 50

 

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I played around with Bottom/Top thickness and it looks like this setting may work. I tested it out on a small part. I will try 1.4mm on my larger print to see if that fixes the holes. I took a picture of the test prints at different settings, but I can't figure out how to get an image on this forum. I pasted a jpg, gif and png file into here, but each time it said:

"You are not allowed to use that image extension on this community"

 

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lol. Bottom/top thickness is the equivalent of shell in the vertical direction. It's hard to give that a word. I don't think there is a word in the english language for the concept. It doesn't cover just *the* top most surface but all horizontally flat surfaces.

As far as posting an image, click "gallery" in the top left corner of this page, then click "upload", then make a post and click "my media" next to the smile icon.

 

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This post as been very useful for another Newbie on their 3rd print!

This time using my own design created in DesignSpark Mech (with which I'm also a Newbie!).

My only problem is I was prompted to upgrade Cura and the firmware today and I'm not sure that went correctly as I'm now getting pillowing which I didn't before, but the photos and the setting are most useful thanks.

 

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Just to be sure, Glitch is American for error aka a funny. Mesh is you model, made up of lots of triangular faces. I just could not work out why you were getting those three little circles in the flat surface. I wondered if there was an error(s) in your mesh, these things can happen especially if you are using free or cheap modelling software, or using a scanned file.

Probably unlikely but the cause has me beat.

 

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