support problem

[wimverbe 0]

I have a strange phenomenon here. I want to reduce support structure when using supports, but the support blocker solution does not suit my needs. so I found an alternative, by constructing arches under the overhangs. The arches never reach an overhang angle of more than 50 degrees. so under the arches, no support will be created. But the support generated by Cura fills the arches with support, only on those spots where my actual object has overhangs. arches placed next to the model are not supported from the buildplate up. how can I remove these unwanted supports? 

 

[geert_2 553]

I do not have an answer to your question, but there might be other issues with your approach:

 

- Overhanging edges tend to curl up, which causes the nozzle to bang into these curls, and which might knock the model off the glass.

- The support material might not stick very well to the steep slopes of the arches.

 

I think it might be worth trying vertical support columns and then a horizontal dummy bridge. Then you only need support material on top of that bridge, so it would consume even less support material. The bottom of that dummy bridge will of course sag, but that doesn't matter, since you throw that away anyway. On top of that support-bridge you could even make some dovetail slots, to make the support material stick well.

 

You could design all this manually, but I think there is an experimental feature from user smartavionics to do this automatically? Some time ago he was working on it, if I understood it well?

 

If Cura wouldn't let you remove the supports, an option would be to disable support totally, and design all the supports in your CAD file, and then assign them to the correct nozzles in Cura. This gives you total control.

 

See these pictures. They are from various different designs and tests, but you get the concept:

 

Edges of overhangs severely curling up, about 1.5mm, so the nozzle banged into these curls, which knocked the model off the glass and created a nice spaghetti.

 

Dummy support bridge, which is removed after printing. Here the support bridge is hanging from the walls of the real object, so it does not have its own legs. But for more stability or if you don't want to scar the real object, you could of course give the bridge its own legs.

 

Dovetail system for adding mechanical grip of the support material to the dummy bridge.

 

 

[wimverbe 0]

Thanks Geert, very useful info! I'll try this tonight.

wim