Internal Supports

[LesHall 95]

Boink! Went my brain when I suddenly realized this concept, the Internal Support, that apparently in retrospect has been nagging at me for some time. What if we changed our slicers to add support on the inside of the part just as we often do (when necessary) on the outside of the part? Wouldn't that boost print speed dramatically?

OK, so we've been using infill since forever, and we have all watched with patience and acceptance that infill is usually necessary. We try to tweak the infill percentage and come up with all sorts of infills and infill only where necessary, which are all helpful techniques, so why use internal support?

Well Im kind of wondering about that. Why is support external and infill internal? Why don't we use external infill and internal support? It seems to me that some sort of branching structural support, placed on the inside of the part, would be more efficient than a fixed pattern.

In addition to that, we have support touching build plate versus support everywhere, how about support from lower internal surface of part to upper internal surface of part?

These are questions that I'd like to discuss. Your comments/suggestions are welcome as always.

Les

Les make it happen!

[LesHall 95]

Okay so I have made an attempt at testing this idea. What I did was kind of poor judgement. Long story short I thought the Ultimaker would fail in printing at the tippy top of this kitty cat model when printed with zero infill, one layer shell, and three layers top / bottom filament. Well the Ultimaker being as awesome as it is, managed to print the top with east, grace, speed, and agility as it always does!

I was hoping to push the printer beyond it's limits then add my internal support idea and have it work, then finally to print with infill for a comparison of apples to apples.

So that idea is shot but with a tougher print that actually does push the Ultimaker beyond it's limits, like a really long bridge, then I will be able to compare.

Les

Les make it happen!

[owen 19]

Hi Les

You can create a cavity inside your model and get your slicer to create support inside that cavity. Btw where's yout cat?

[LesHall 95]

Hi Les

You can create a cavity inside your model and get your slicer to create support inside that cavity. Btw where's yout cat?

that's a good idea, I can use meshmixer to hollow out the piece, but how can I get the slicer, in my case Cura but really any slicer to create support inside of it? Do I have to remove the bottom? Or will using support do it?

Alas, my cat Schrodinger disappeared in an ultraviolet catastrophe! So sad...

Les

Les make it happen!

[mastory 44]

I like it. Been thinking for a while, why can't 'external support' be used inside a model for quicker printing? This could save considerable filament and even better alot of time. An angled support structure inside a model could save even more. I don't recall what the new Cura calls the tapered support, but that is already implemented for external support. Why not make it possible inside a model?

[LesHall 95]

exactly

[LesHall 95]

If you have been thinking of it and I have been thinking of it, I bet a bunch of others have too. Sounds like an idea that's ripe for action! Any Cura programmers around?

Les

Les make it happen!

[owen 19]

If you have been thinking of it and I have been thinking of it, I bet a bunch of others have too.  Sounds like an idea that's ripe for action!  Any Cura programmers around?  

Les

Les make it happen!

I think cura does support inside a cavity. You just have to tell it to do support everywhere not just from build plate.

[LesHall 95]

I think cura does support inside a cavity. You just have to tell it to do support everywhere not just from build plate.

I tried it and it worked! This will create a major speedup for me, thanks owen!!!

[LesHall 95]

Yay it worked... sorta kinda, but not really. See this photo shows that the support for the head and ears goes all the way to the ground. I want to see it grow from an internal spot to the place unside the top of the part where it is needed. Then later we can add it coming from an angle from a side wall, even better!

Les

Les make it happen!

[changedsoul 2]

Has anyone come up with a solution? Its not on Cura 2.7, and I still dont see a internal support option.

I am trying to print this here pumpkin as hollow as I can, but the top will always fail because nothing is inside. A nice centered column would be great for the top layers to stick to.

Anyone have any thoughts?

[DaHai8 74]

Did you try Support -> Support Placement -> Everywhere ?

That will add support inside and outside your model, basically 'Everywhere' it is needed.

[LesHall 95]

This is an idea on this topic from one year ago. In this case the internal support is optimized for low material use. It could be a tree of rings, etc. By now surely this is in practice, just in case it isn't here is an image to convey the concept.

[LesHall 95]

Also along the same lines is an extra recent idea: dissolvable infill for single-extruder machines. In that idea we use bridging and other techniques to make very thin, fine structures that perform the support role, yet are so delicate that a bath with solvent will erase the structure.

Along with this concept is a parallel notion in which the dissolvable structures may be external and used for printability. A case in point is printing springs or stalks.

I am sure that researchers have explored these ideas, I just wonder what keeps them from appearing in practical use (i.e. in Cura). Maybe I am just uninformed?

Les

[changedsoul 2]

Did you try Support -> Support Placement -> Everywhere ?

That will add support inside and outside your model, basically 'Everywhere' it is needed.

Yes I tried "everywhere", the image I posted was with that setting, and nothing inside was generated.

[DaHai8 74]

Yes I tried "everywhere", the image I posted was with that setting, and nothing inside was generated.

That is odd, it should have generated internal supports. Maybe a bug in Cura or an issue with the stl file.

Is the stl file available somewhere to download and examine? Like thingiverse...?

[changedsoul 2]

Yes I tried "everywhere", the image I posted was with that setting, and nothing inside was generated.

That is odd, it should have generated internal supports. Maybe a bug in Cura or an issue with the stl file.

Is the stl file available somewhere to download and examine? Like thingiverse...?

Yes it is in fact available. Here is the link: https://www.thingiverse.com/thing:1042654

I scaled it up quite a bit...perhaps thats causing the issues?

[DaHai8 74]

Ok, the pumpkin stl file is not hollow. You set infill to zero (?) so Cura still sees it as a solid object and won't put support inside a solid.

There are some Experimental settings in Cura that might help, as well as possibly placing a pillar stl file inside as a manual support - but I have no experience with either of those areas.

Maybe someone else who's more familiar with those particular Cura settings can help.

[changedsoul 2]

Ok, the pumpkin stl file is not hollow. You set infill to zero (?) so Cura still sees it as a solid object and won't put support inside a solid.

There are some Experimental settings in Cura that might help, as well as possibly placing a pillar stl file inside as a manual support - but I have no experience with either of those areas.

Maybe someone else who's more familiar with those particular Cura settings can help.

Ahhh I see. Yes I set infill to zero. Didn't even dawn on my that its solid, lol. I just seen it as a pumpkin that it hollow. I will try some of these experimental options. Do you know what they might be called?

[DaHai8 74]

Another option is to edit it with Meshmixer and have it actually hollow out the object, then when you bring it into Cura and Support->Everywhere, it will put internal supports in the pumpkin.

Maker's Muse has a nice video on how to hollow out an object in MeshMixer:

[changedsoul 2]

Another option is to edit it with Meshmixer and have it actually hollow out the object, then when you bring it into Cura and Support->Everywhere, it will put internal supports in the pumpkin.

Maker's Muse has a nice video on how to hollow out an object in MeshMixer:

Thats a great Idea, thanks for the video.

[DaHai8 74]

Ahhh I see. Yes I set infill to zero. Didn't even dawn on my that its solid, lol. I just seen it as a pumpkin that it hollow. I will try some of these experimental options. Do you know what they might be called?

There's Experimental->Hollow Out Object, Experimental->Enable Conical Supports, Special->Drop Down Support Mesh.

Not sure what exactly they all do, but they sound promissing!

[kmanstudios 1,120]

You can also just click on "Hollow out objects" in the experimental section. It allows for the printing of supports. But you cannot have your infill set to zero. It takes that infill number and applies it to a PVA support system inside the object.

[changedsoul 2]

Thanks guy. seems the hollow out object works...sort of. The supports seems to want to start in mid air, lol. No worries, I will do the meshmixer way and add some internal supports manually.

[kmanstudios 1,120]

Thanks guy. seems the hollow out object works...sort of. The supports seems to want to start in mid air, lol. No worries, I will do the meshmixer way and add some internal supports manually.

 

that would depend on your internal support structure. If you use gradual infill, it will replace that with PVA and do as you say.