[ADDED] Simply fix to increase strength of Infill

[smartavionics]

Hi,

Personally, I don't have a problem with the infill strength but what is a very big problem for me is S3D's inability to extend solid layers far enough underneath raised features such that the solid layers don't have holes where the raised feature meets the solid layer. Increasing the infill extrusion width (to make the infill stronger) only makes this worse because the holes are bigger. By comparision, Slic3r, will run the solid layers quite a way underneath the raised feature and the result is both strong and handsome.

Cheers,

Mark

[jimc]

Mark, i do know what you are talking about. I have seen and had this happen but unless your infill is extremely low % then thats all in the settings and not really a slicer issue. Usually printing too hot will cause this. I have had this on a rare occasion pop up but i can correct it no problem. In a couple years of printing everyday on 3 printers, i can count on one hand the amt of issues i have had with this.

[smartavionics]

We're talking PLA at 200C and at least 30% infill. Too hot? Too sparse? I don't think so. The solid layers simply don't go far enough under the raised feature. The solid layers stop before they reach the infill filament that's beyond the edge of the raised feature so they finish in mid-air and shrink back to cause holes. They got it wrong.

[jimc]

at 30% infill it would be normal for 3 top layer to give you something solid with no holes. how many top layers do you have going down? also what does your infill look like before the solid layers go down? is it all perfectly smooth or is it broken at all with incomplete lines and little pieces stickup up?

[hairykiwi]

I began using S3D last year and except for the problem being discussed, I'm generally very happy with it. I'll continue to recommend it for the things I believe it still does better than Slic3r and Cura, but it is very frustrating to see that S3D v3.0 still hasn't addressed the issue of poor infill structure design. It really does detract and leads to otherwise unnecessary modes of failure in some printed parts.

To those who say, "design for manufacture" - I couldn't agree more. However, I believe the manufacturing process itself can be improved by improving the nature of the infill that S3D is generating. That S3D enables the ability to tweak infill is some mitigation; but for this particular problem S3D then fails to live up to its name of simplifying the printing preparation experience - especially when the slicers already mentioned generate ideal internal structure without any effort on my part, despite their other short-comings such as poorer quality of automatically generated support structure.

Here's a good example of the problem; a bicycle light clip, max xyz size: 31x33x18mm.
The problematic feature is the horizontal spring tab (2.1mm thick) which protrudes from the vertical wall (2.5mm thick):

In the next screen capture, the image to the left is indicative of how S3D does not extend any of the top (3) and bottom (3) layers from the tab into the wall. On the right, the single central layer is extended into the wall, though to little overall structural benefit:

After only a very few flexure cycles of the tab, the lack of significant infill cross-over from tab to wall results in the tab breaking off quite cleanly, right along the wall-tab interface boundary.

By comparison, In those parts printed using Slic3r or Cura, when the spring tab fails it does so further out from the wall, in the tab itself:

That is something I can overcome, (designing for manufacture) by making the tab thinner.

- Hamish

[smartavionics]

Sadly, version 3 doesn't fix this bug.

[scobo]

V3 is out now, apparently.

[JoeJ]

For reference, they fixed two big things in the new version. The new infill options give you a lot more control to make the parts stronger (which is what this thread was about). They also fixed the issue where the solid layers didn't overlap enough with the perimeters. For proof, here's two comparison pics below. So it's a huge upgrade for part strength!

Version 2.2.2

Version222.png (73.91 KiB) Viewed 6691 times

Version 3.0.0

[S3D-Jason]

As mentioned above, these features were all implemented in the latest 3.0 release.
- The issue in the post above where perimeters weren't being bonded fully to the layers below has been fixed
- The request of the original poster to have an option to print multiple infill angles on the same layer has been added. Just go to the Infill tab and enable the "Print every infill angle on each layer" option. For example, this could print both a -45 and +45 degree infill pattern on the same layer for extra strength.
- Many new infill patterns were added such as grid, honeycomb, triangular, etc. See the Infill tab for these new options.