Inner supports for object with 0 infill

[DidierKlein 729]

Hi all,

I need to print a skull (http://www.thingiverse.com/thing:70717)

The thing is i need to print it with 0 infill and now bottom but i'm pretty sure it will fails as there are inner overhangs (the orbits and nose bone for example).

I added supports myself with DesignSpark Mechanical (just created boxes that go up to these parts). I've done a little test print for this and it seems to be working.

I'm wondering if the top of the skull will print correctly. And i'm not able to create some supports myself that will come off as easily as the support generated by Cura.

Is there a way to add support at the inside of an object or do i have to create them my self?

 

[onkelgeorg 36]

Hi Didier,

you mean like that?

http://www.torhoff.com/3d/Celtic_Skull_singlewall_sup.zip

Did it just quick and dirty in the lunch break with meshmixer (newest version).

May be you should make the support poles thicker.

Here is how:

- Import stl in Meshmixer

- Rotate it in the right position

- 'Edit' -> 'Plane cut' - type: cut, fill: no fill, check 'hard edge' -> Accept (make sure the the small blue arrow shows to the side you want to cut away)

- 'CTRL A' to select all -> "EDIT" -> "Flip Normals" to flip inner and outer shell

- "Analysis" -> Overhangs (adjust parameters if necsessary) -> "Support all Overhangs"

- done

hth

Joerg

Edit: link corrected

 

[DidierKlein 729]

Thanks for the tip Joerg,

I can't download the file you linked...

I've already tried meshmixer but i'm always struggling to make the object in the right position.

I will have a look at you method tonight if i have time

 

[onkelgeorg 36]

sorry for the broken link, here is the correct one:

http://www.torhoff.com/3d/Celtic_Skull_singlewall_sup.zip

 

[DidierKlein 729]

Yep thanks i should probably try this way it looks better than my custom support

 

[DidierKlein 729]

Thanks a lot, following your advice and the excellent stuff from illuminati's blog http://www.extrudable.me/2013/12/28/meshmixer-2-0-best-newcomer-in-a-supporting-role/

I think i managed to have something that will work nicely and without fighting with my pc to make it

Will be printing a test part for the top in a couple of minutes to see how it goes.

 

[onkelgeorg 36]

great, please let me know how it worked, may I will print it too in colorfabb XT and put some LEDs in it :mrgreen:

 

[DidierKlein 729]

Well i made a test in natural PLA and i ended up with the same idea ^^

Anyway supports do their work but they seem to go through the skull and as i print with 0 infill it leaves a hole...

Back to meshmixer ^^ i guess it comes from the Flip normals trick?

 

[onkelgeorg 36]

Back to meshmixer ^^ i guess it comes from the Flip normals trick?

 

yes, correct, that's the key

Edit: May be the normals must be flipped back after adding support? Didn' test it, just an idea

 

[DidierKlein 729]

First thing i tried but nope the support structure seems to go through the skull so i guess i have to figure out another way or do the top of the skull test again without support to see how it fails (if it fails)

 

[onkelgeorg 36]

ahh too bad, I cant start a print today. May be I can test it tomorrow evening.

we should keep in touch regarding this issue

 

[onkelgeorg 36]

Ok, I tested it and the print failed. The support goes through the top. So another idea is required :(

[DidierKlein 729]

Yes this is what i noticed too on my test print.

Didn't find a way to do this unfortunately, so i added a cylinder in the skull after cutting the base with meshmixer. I don't really know how i managed to do the following, while playing with flip normals and analysis to repair the model i managed to make the cylinder be an outer shell in cura.

The i set some infill that left the cylinder hollow and filled the rest making support for the overhanging parts. The print went good.

There must be a way to print this hollow but i'm not good enough with cad software to do this.

This is a little timelapse of the skull. I had to use supports from cura for the side parts too.

 

 

[onkelgeorg 36]

Hi Didier,

it came to my attention that you managed the print, as you showed off here:

http://umforum.ultimaker.com/index.php?/topic/467-post-your-latest-print/?p=50031

How did you finally manage it?

Cheers,

Joerg

 

[DidierKlein 729]

I explained it just above. Not the best solution but it worked.

It seems that nicolux did something similar with his yoda that didn't finish, you can clearly see some infill inside close to the shell.

Unfortunately it isn't ok if you want to light it up from the inside.

I didn't try other slicers maybe some have this feature? I doubt it but who knows

 

[onkelgeorg 36]

Ah, ok. I missed your answer :oops:

I'm still thinking on this issue but heaven't found a proper solution too. So may be time will tell