Gaps in tree support, but even moreso during printing.

[theoky 0]

As mentioned here already

I encounter those gaps as well when slicing for tree support:

 

The strange thing is that these small gaps print completely different as big gaps:

 

This has been sliced with Cura 4.9.1 and mesh tools didn't complain about the model itself. Printing has been done on an Anycubic I3 Mega.

 

Is this a bug or did I use wrong settings?

 

[GregValiant 1,251]

Geez, that could be a lot of things.

You might check your Support Flow and Support Line Width.

A "Tree Support Branch Angle" greater than 45° can cause this too.

Zooming in to the right side of the skirt you may be under-extruding (the lines aren't welded together).

What was the print temperature?

How did the main model turn out (cuz you're going to throw that portion away)?

 

It appears that the gaps are caused by the filament not adhering at certain points.  That results in a straight line (like a bridge) so instead of going from A to B to C it's going from point A to point C because it didn't stick at B.  The fact that it kinda shows up in preview makes me think it's line width or flow.  There are a lot of suspects though.

 

 

[theoky 0]

Thanks for your thoughts on this.

 

Temp. was 197 (on the lower side for the used PLA), tree support branch angle at 40°. The other paramters wer the defaults from the tree support, flow parameters were unchanged, too. Print speed was set to 40mm/s.

 

I don't think that the gaps are caused by bridges because I watched the print head going straight between those points. I don't have a video of that part, only of a later time. In this image from that video (sorry, no better quality) you can see (somehow) the edges near the yellow marker line:

 

They seem to be inverted and not caused by bridges.

 

The main model didn't turn out so good, but that's because it contains overhangs which warp during printing. Unfortunately the warping leeds to pressure on one side of a supported part by the print head. The support from the tree structure is to weak with the current settings and so these parts break loose when the print head moves into the warped area (does this make sense?).  It is this model, btw: https://www.thingiverse.com/thing:4750833, scaled to 90%.

 

I think, this model will work better with classical support and some additional support structures for part of the wings...

[GregValiant 1,251]

That is a very difficult slice and is totally dependent on the way the support is handled.  Here is my take on it.  40% of the filament is used in the support.  The 3mf file may give you a starting point.

My stuff is mostly functional prints.  @kmanstudios is much more of an artist than I am.  Maybe he'll have a take on it.

GV_Charizard.3mf

[kmanstudios 1,120]

I do not use tree supports, so I am not really helpful here.

[Smithy 1,144]

He is also called Mr. PVA 🤣

[theoky 0]

Thanks a lot. I think I'll give it a shot with a classical support structure and some additionally added support elements. But this could take some time...

 

At least it's an opportunity to learn a lot ... 😉 

[kmanstudios 1,120]

1 hour ago, theoky said:

additionally added support elements

I have used placed supports for various reasons. Sometimes to physically hold a piece in places like a small pyramid underneath a part to hold it in place so it does not get knocked off the support structure. Like this:

 

In this case the character's butt got knocked off the PVA supports after two days of printing. 😬 The manual supports pinned key areas while PVA did the rest. That is when I added the manual supports. Manual supports were added after that fiasco. Got a nice print after that.

 

 

Edit: They popped right off and then a quick X-Acto blade shave to do final cleaning. But they supports really just popped right off cleanly because it had such a low point of contact with the main body. I just shaved it off to make sure everything was contoured properly.

 

Edited June 16, 2021 by kmanstudios