Supports not in contact with part being printed

[DaynoART 0]

Cura was placing floating supports that were not rooted or crested in contact with my model. Where they were supposed to meet with the raft, they made contact fine. Where they were supposed to make contact with the model, there was a gap. By reducing Z bottom-distance and Z-top distance to 0, I've managed to get the support immediately adjacent to the part, but never quite connected to it. Tree supports do the same thing - not connected to the part. I've returned Cura to "factory settings", and I've even deleted and re-installed cura. Same problem. I'm not sure what else to try?

 

I'm using Cura 4.7 and the ultimaker S5

[GregValiant 1,321]

With "Support Top Distance" and "Support Bottom Distance" at zero, and "Support Distance Priority" set to "Z overrides X/Y" The first part layer above the top of the support should be held up by the support.  A support isn't the bed and so the nozzle can't flatten the extrusion as well as on the bed or on a well supported layer.

Looking at the supports in your image, I'd be nervous about them falling or being dragged over by the nozzle.  As soon as the plastic leaves the nozzle it cools and becomes like taffy.  It can have enough strength to pull over something tall and skinny.

[DaynoART 0]

Yeah. I've been messing with what you've described. I've been able to strategically avoid the problem. I'm realizing that the part featured in my post is apparently a particularly difficult one to properly support. The towers that cura seems to want to make are unstable enough already, but as you can see by looking at the tower on the right, its basically printed on nothing. THAT is the one that gets knocked over. Either that, or it turns the print misses the start of the support completely and turns the whole layer into spaghetti (mild exaggeration)

 

[geert_2 558]

What about modeling custom supports in CAD? In that way you can make a wide and stable support in the same material as your model. And only a thin dissolvable support-layer in-between the support and model. Not sure if this would work, I have never tried it yet, but it might be worth experimenting on a small test-object?

 

To make the dissolvable support material stick better to the custom support structure, you could add sort of dovetail ribs on top of it, so both interlock. See this concept-pic:

 

 

 

[Torgeir 248]

Hi there,

 

Is not this a place where to use the tree support?

 

But sure, -just from the picture you show us..

 

Thanks

 

Torgeir.

[GregValiant 1,321]

Yes, tree support.  It would be broader based and that second one wouldn't grow on the part but come around from the side.

[DaynoART 0]

That definitely helped the bottom stick better.but the top is still very much an issue. I think that the problem is very much exacerbated by the delicate footing and shape that the snap-fixture forms on top of the support. I have since tuned the printer more effectively and have not had this problem on any but this model. The problem is that there are two of the same fictures on the part, and they're 90 degrees apart. The problem is inescapable! And/or, the part may just need a little redesigning. Is Greg Valiant a reference to Who Framed Roger Rabbit? Isn't that the name of the P.I.'s murdered brother??

[GregValiant 1,321]

It was the brother's last name (Valiant & Valiant). but it's also my middle name.  Mom always loved the comic strip character Prince Valiant.