Uneven Cylinder walls with Cura

[FTsabrov 0]

Hello all,

 

Couldn't find what I was looking for through google, so asking here. I modeled a part in Inventor that has a rather thin cylinder at the top, which has had trouble printing. The thin cylinder came out lumpy, but I don't think this was entirely a cooling issue. The gcode generated shows the thin cylinder portion to have ridges every few layers, making it uneven. Is there a solution to this? example attached.

MPROM_0_125 in connector B FIX.curaproject.curaproject.3mf

[Job_van_gennip 23]

I tried to open it as well and i get exactly the same failure. So it is in the model for sure, i am however no expert in inventor so only thing i could think of is saving as an stl and try again.

[FTsabrov 0]

I've tried to save it multiple times. I figured it was some issue with the way the triangle mesh is built, but smoothing it out in Meshmixer didn't help at all. The file I uploaded has been "Meshmixed", looks exactly like the original. Will look around Inventor forums. Thanks!

 

Though, Cura seems to recognize the shape as a cylinder (as seen in the grey outline). Maybe it's just an issue with how Cura slices things?

Edited February 21, 2018 by FTsabrov

[Job_van_gennip 23]

But did you also try exporting it as an stl?

[FTsabrov 0]

Is there a way to get an stl from Inventor other than exporting it as stl? That's what I've been using.

[FTsabrov 0]

Update: checked in slic3r (through Repetier Host), and the model slices perfectly. This is just a Cura issue, nothing wrong with the model.

[AbeFM 35]

You might post that to 

It seems related (in that the slicer is missing the boat here a bit on matching the shape it's slicing)

[yellowshark 153]

You get my daily brains award for using your brain and trying another slicer. I doubt that Inventor would create such an error. We use Solidworks, i.e. Inventors main competitor and vice versa, and always get perfect meshes when exporting to .stl; never had a duff one.

[AbeFM 35]

YellowShark - you might check the post immediately proceeding yours. I've had slicing issues with SolidWorks exported objects time and time again, hence my bringing up the subject in this thread.

 

I'm not convinced there's out-and-out errors in the STL, I think it's under-complete, like the ones SW puts out. At the right settings, you won't see the errors, make the slightest of changes and things can get pretty unreasonable.

 

His error looks more like... I forget, I posted it a year or two ago - thin walls of uniform thickness would get holes or even more strange only have certain segments going through an otherwise empty space.

 

And we're not going to fix it by saying "It hasn't happened to me".

[thopiekar 46]

@FTsabrov, interesting to see how Cura behaves to you while looking at your first post.

Especially, that it decides to use once circles with the correct diameter, then again with a smaller diameter.

Since it seems to be a model which seems to be rotated around the Y-axis, could you be so kind and make a 1/4 cutout. I can imagine that you have something inside the model, that makes the slicing engine decide to use these circles.

 

Additionally, I'm also curious how and whether the SolidWorks plugin I'm maintaining at the moment, solves the issue or not.

I introduced there 3D printing profiles, which care about converting your model in such a quality, that it fits to the needs of 3D printing on desktop printers.

Would be great, if you could give it a try and write some feedback about it!  

[AbeFM 35]

I would expect it to be the same? Your macro uses the same SW internal STL export routine, right?

 

CURA keeps crashing since I loaded your file. You have two extruders and assigning something to the other also makes it crash.

 

I "fixed" the object in MS 3dBuilder, and attached it

.

I still get problems, but less than you had.

MPPROM_fixed.3mf

[AbeFM 35]

Sorry to keep beating up the thread... But I would like to see this stuff solved!

 

 

I took the same two models (original and "fixed") and sliced them with MY printer, and it worked fine.

 

I played with things like exclusive/middle/inclusive filling, etc, but I think the issue is with your printer set up. I have no idea what, I don't do dual color printing for another week or so. :-)

[FTsabrov 0]

Pardon the radio silence. Yes, I have this set to print on the second extruder, it's what I had TPE loaded in. It's a problem where if your extruder set to print the part has a print temp of 0, Cura crashes. There is nothing inside the model, either @thopiekar. I've heard that Cura doesn't handle small perimeters well, so this might be the issue. Not sure why @AbeFM has had such better results, an imperfect mesh shouldn't have caused all those rings. Can't see why my settings were causing this, either. Regardless, I definitely think that this is a Cura issue, and that the dev team should look into solving this.

 

@thopiekar, I don't have the model on hand right now, hopefully the attached screenshot of the sliced model will do.

 

EDIT:

Also of note, the rings are almost entirely removed when the model is oriented upside down. I've printed it this way (with supports) and it came out nicely, aside from inevitable TPE stringing. No change in settings other than supports activation and dual extrusion tower. Odd.

Edited February 26, 2018 by FTsabrov
Added info.

[AbeFM 35]

I don't know what causes these issues, but it's VERY specific to where the object is, how it is rotated, etc. Any move will change it (perhaps float it a mm over the bed)....

And yeah, anything you can tweak in the printer settings which might make the issue go away, the more likely the dev team can fix it.