Challenges with Support Structure in large prints.

[Alan Timm]

I'm curious if anyone else has seen this with the support material during large prints.

Is there a combination of settings or strategy that you've used to resolve the support issue?

Rostock Max
E3D V5 hotend
Kisslicer, course support
20 perimeter, 30 infill, 40 sparse infill
bed at 120c
printing at 270c (any lower and the model splits multiple times)

It looks to me that its some type of additive buckling. but only on the long support runs.  Each layer for some reason slightly compresses the previous one, but it's always the right side of the model regardless of the model's rotation on the build plate.
I've tried it with sheath main support as well, and the buckling still occurs. (Although the edges turn out alot better, no splitting when sheath main support is selected)

I suspect that it's happening on the right hand side because of how the support structure is laid out.
It's almost like there's a certain maximum line length before the curling and buckling occurs.
You can kind of see that happening from about the center of the print. That first support line that cuts across the middle is the longest run, as well as all the support lines after it.

It's an annoyance with single head printing, but the buckling interferes with the second head and makes dual extruder prints problematic

In the first image, you can see the support layers buckling on the right hand side of the model. That side always buckles, regardless of the models rotation on the build plate.

In the second image, you can see the buckling from the side view. These are two different prints of the same part.

[Alan Timm]

Here's another very large print with large spans of support structure.

lonesock, do you have any ideas on how to make the support material behave better?

The only pattern I've observed so far is that each run of support only warps when the run is over a certain length, let's say 4cm for now.

This example has alot of very long runs, so it's easier to see than on the previous example.

Everything on this print and printer is tuned, extrusion multiplier, extrusion width, everything.

It's only mostly an annoyance with single extruder prints, but when printing with dual extruders, the "not-active" extruder always catches on the raised edges of the support, which can dislodge the print or catch the effector.

Thanks for your help!

[Matej Rozman]

Hi Alan,

There is nothing wrong with the support structure, you are just using ABS in a non enclosed printer. Try to cover printer with something while you are printing, you will see the difference right away.
Also, you can turn sheath support on, this feature will create perimeter around support, but be carefull, can be a pain in the a** to remove from difficult to reach places.

Happy printing!

Dne ponedeljek, 09. junij 2014 19:20:16 UTC+2 je oseba Alan Timm napisala:

[Alan Timm]

Hey Matej,

Thanks for taking a look, I really need to talk to others that are able to print large objects like this.

The printer is enclosed, so the temperature should be uniform, aside from the temperature difference between the heated bed and the top of the printer.

I haven't tried actively heating the build chamber yet, but I wonder if I kept the entire chamber at, say 70c if it would help.

I've also tried the print with "sheath main support" enabled, and the results are the same, although the edges are definitely tidier.

Even with sheathed support, I see the same warping in long runs of support material.I suspect strongly, that if it were possible to "section" the support structures so that each run was less than 4cm or so, it would eliminate the issue.

It's currently mostly an annoyance on single extruder prints, but it's interfering with the second extruder on dual extruder prints.

Alan