Can Cura optimize inner shell quality?

[aroth 1]

When printing hollow parts that have both an outer and an inner shell (for instance, vases, cups, rubbish bins, etc.), I've noticed that the interior shell tends to be far less 'polished' looking than the exterior shell at the same point. This is particularly evident when printing something like this:

http://www.thingiverse.com/thing:45315

The exterior looks great, but the interior is very rough (and also tends to be cluttered with thin threads of filament that have to be manually removed after the print...though I think playing with the 'retraction' settings can help reduce that?). Is this because Cura prioritizes the exterior surface(s) and/or doesn't worry about the internal ones since it expects them to be hidden? And is there any setting in Cura that will cause it to print internal surfaces as nicely as it does the external ones?

 

[yellowshark 153]

Well I am looking at a piece where the inside surface is as perfectly smooth as the outside surface. Using a Faberdashery filament run at 200 microns, 30mm/s, 210 extruder temp. I will admit that my piece is vertical whereas a vase has probably got an incline in the geometry, which could I suppose have an impact depending on the angle. But I have not experienced the problem you describe - I wonder if you arejust printing too fast. It would be helpful if you could post your settings, total width of outer shell to inner shell, how many walls you defined, plus a picture of the poor result.

 

[aroth 1]

I was printing at 100 microns, 50mm/s, 210 extruder temp, 65 buildplate temp, retraction enabled. Here's a picture of the exterior surface:

...and here's the interior of the same object:

What you can't really tell from the interior shot is that the bands of blobby parts repeat with great consistency and regularity. They run around the entire interior circumferance, and they occur at regular intervals, always at the top of the little oval features. The regularity of the artifacts is what makes me wonder if maybe Cura is paying less attention to the interior surfaces since it expects them to be hidden in the final part.

The design I printed is available here: http://www.thingiverse.com/thing:45315

 

[txesc 1]

Do you have combing switched off?

[Daid 306]

Which version of Cura are you using?

 

[aroth 1]

Do you have combing switched off?

 

I don't believe so...unless it's off by default? I haven't changed the combing setting from whatever it starts out as.

 

Which version of Cura are you using?

 

14.07.

 

[yellowshark 153]

Ok it is the model. I downloaded it into Cura then copied the Gcode across to Repetier Host and looked at the inside (you do not have the fidelity in Cura to do this). The blobs are on the interior of the external indentations and the surface is a mess.

I have just tried to load it direct into Repetier Host so I can slice it with Slic3r but the model is taking a millennium to load (I scaled it down to 25%) to see if the result is the same but it clearly is a duff model unless Cura has screwed it but given the load time, it is still only half way through after 15 mins, I am sure it is the model.