Gaps in perimiter walls

[Guest Lemaru2]

Hi,

I have been using Cura 15.05.6 for quite some time and thought it was about time to upgrade to Cura 3. Got it all set up as close as possible to my Cura 15 settings however every print suffers small gaps in the perimeter walls on a print, the same gaps do not show in the layer view.

I have attached a picture which shows the gaps (noticeable on the Benchy chimney). The one on the left is Cura 15, the one on the right is Cura 3.2 (3.3 does the same thing). This makes for the chimney being extremely fragile as just pressing on it causes it to snap off, whereas the one printed with Cura 15 is perfectly fine, has none of these gaps and does not easily snap off. 

Also tried with Slic3r and this also prints fine without these little gaps. Have made sure that Coasting is disabled. Have a retraction of 1mm (direct drive extruder), Printing at same temp and speed as Cura15 and Slic3r. Have tried various Z seam options and no change. 

 

What other settings can cause this? It has to be related to Cura 3.x as every other Slic3r with the same settings prints fine. 

It may not look that bad but it effects EVERY print that is sliced with Cura 3.x. So for now I have to stick with Cura 15 which gived a great result every time, no patchy gaps in walls.

Any help much appreciated

Lemaru

 

[burtoogle 516]

Please attach the gcode so I can take a look at it. Thanks.

[Guest Lemaru2]

Here you go. I just printed the roof of the benchy rather than the whole thing as that is where it is most noticeable (though it happens all over). Also included a photo showing the defects.

This was printed at 0.28mm layer height to save time, but same issue at 0.2mm

If using Cura 15.04.06 it comes out fine. 

Thanks

Cura 3.3 Benchy Roof.gcode

[burtoogle 516]

Hello @Lemaru, I don't really have an answer for you just an observation. When you look at the lines that are used to print the chimney, you can see that one of the inner lines is very broken. This is due to the line overlap compensation which is trying to fit a line into a space that isn't wide enough for it. The overlap compensation has some problems and can often produce ugly crap like that. Unfortunately, apart from turning off the compensation, there's not much you can do.

 

 

BTW, do you know what the resolution of your printer's extruder (in steps/mm) is? What type of printer is it?

[Guest Lemaru2]

Disabling that setting had a great improvement in the skin and there's no more gaps. Admittedly the overall surface still isn't as good as when using Cura 15.x. though Slic3r gives the best finish overall but has other issues itself which I don't like at all so try and stick to Cura.

 

I did find increasing the wall thickness also helped otherwise the infil between the inner and outer wall caused the skin to have a really rough finish around the front of the benchy. Increasing this puts another perimeter wall on rather than infil. Still not perfect but does look better.

 

It was a CTC i3 (geeetech clone) but has had many bits changed of modified. Currently the extruder steps per mm have been calibrated at 97.069, I checked this again and all seems fine there.

 

It's kind of hard to see in the pictures but the one on the left is with the compensation turned on, and the one on the right is with it off. The chimney also no longer snaps off easily by pressing it like it did previously.

 

The three benches show the results from the three slicers with the settings set as close as possible as I can get them. (Top is Cura 3.3, right is Slic3r, and bottom is Cura 15). 

Edited May 7, 2018 by Lemaru2