With solid infill top/bottom enabled, getting infill on sloped sides

[dsmudger 0]

Hi,

Setup: Cura 15.0.04.6, Overlord Pro delta printer.

Does anyone know if it's possible to control the slope angle at which a wall is considered a top or bottom?

I'm printing, with 0% fill density: http://www.thingiverse.com/thing:853358

And with 'Sold infill top/bottom' enabled in Expert settings, I'm seeing yellow infill in layer view, on some but not all of the sloped walls:

This infill does indeed get printed, and spoils the look of the affected edges as I'm printing in translucent PLA.

Printing with top/bottom infill disabled, prints a great looking model, but then a very small area on the very tip of the cat's head (1mmx2mm), and the whole bottom, are left open.

So I think what I probably need is to be able to adjust something similar to 'overhang angle for support (deg)' but for top/bottom infill?

Thanks!

Edited May 5, 2017 by Guest

[DaHai8 74]

Try "Spiralize the Outer Contour"

Expert -> Open Expert Settings -> Black Magic -> Spiralize the Outer Contour

You'll probably want to set your Shell Thickness equal to your Nozzle Size...

[burtoogle 513]

Unfortunately, spiralize won't produce a good result for a couple of reasons:

a) the top of the head is flat (spiralize doesn't produce good results for surfaces with shallow slopes).

b) the cat has two ears! (you can't spiralize multiple regions, there has to be just one outline).

[DaHai8 74]

I have spiralized multiple regions. It does work. But you are right, flat tops don't come out well.

[bagel-orb 61]

Does the same thing happen in cura 2.5?

[burtoogle 513]

It still happens with the master branch. Personally, I think we should allow the skin shrink to be able to reduce skins that are narrow to nothing. I believe that would solve this problem. Obviously, if the skin slope is shallow, gaps could appear.

As an experiment, I modified CuraEngine to allow the skins to be shrunk to nothing and here's what the cat's insides look like:

Edited May 14, 2017 by burtoogle

[burtoogle 513]

I printed it out scaled 200% using translucent grey PET(!) and apart from a small hole on the top of the head it came out really well. I think that if I had used 4 top layers instead of 3 and tweaked the expand skin setting it would have come out purrfectly!

[dsmudger 0]

Thanks for the replies. I did actually manage to get Cura 2.5 working with my printer (technically not supported but now that Delta printing is back in Cura, it just worked).

And I got a good result with that by carefully choosing the number of top and bottom layers until there were none on the sloped sides. This allowed a print with nice clear sides and also no hole in the top.

The top is a bit thin, it'd be better with an extra layer or two, but then there'd be the extra material appearing on the sides.

Not sure if I understand the issue quite correctly but it seemed like a setting similar to Support Overhang Angle, but in the 'Shell > Top/Bottom Thickness' section (maybe it'd need one each for top/bottom) would be a way to tweak this for a given model?