Extra Support Material

[dschmid4 0]

I'm getting support material on the outside of my model, and this is ruining the surface.   See attached pics.  I tried various settings in the Cura slicer and can't seem to affect this.   What setting / modification do I need to change in order to eliminate the support material showing up on the outside of this model?   Note:   I'm printing box halves with the open side down, thus the support material is needed underneath, but not on the outside of the outer wall.

[gr5 2,172]

Make sure "support x/y distance" is around 1mm or even higher - this will move it away from your walls.  Also "support distance priority" might have to be changed to "x/y overrides z" depending on your part shape.

[johnse 31]

Reduce “support horizontal expansion” to zero. 

[burtoogle 513]

Turn off "Use Towers".

[gr5 2,172]

7 hours ago, johnse said:

Reduce “support horizontal expansion” to zero. 

 

This may also help.  But I didn't mention it because for 90% of prints you want this at the default 3mm for very good reasons.  I guess the quick summary is that pva sticks to the glass bed well but not to pla very well (it sticks, just not well).  So you want the pva portion to have a path all the way to the glass.  "support horizontal expansion" often (usually?  sometimes?) fixes this issue and makes a disaster print into an excellent print.  Depending on your model.

[johnse 31]

In this kind of situation where the support is fully inside the external walls, the horizontal expansion serves no purpose and puts thin walls of support on the outside.

 

These thin pieces almost invariably break off and contaminate the PLA portions.