Help with blocking supports

[saline 0]

I'm using Cura 5.3.0 on W 11 system.  In the attached file, I'm trying to block the lower supports that support the overhang, and leaving the supports for the elongated hole above it.  I thought I blocked off the lower supports with the cubic block, but when I slice the supports still show up, and they also print.  What have I missed?

CE3E3V2_DriveHolder.3mf

[GregValiant 1,489]

There are a couple of things.

You have Support Horizontal Expansion set to 0.8.  That's causing those upper supports in the slot to hang over the outside of the model.  As a consequence they are also growing up from the build plate because they are cantilevered outside the model.

The second thing is that your support blocks aren't touching the red area that indicates the overhang.

I've multiplied your model.  Your supports are on the left, the support I put in is on the right, and the Support Horizontal Expansion is "0".  A support blocker needs to touch the overhang.  Whether the blocker goes down and touches the build plate doesn't matter.

[saline 0]

Thanks.  That was very helpful.  I reduced the overhang support to 0.0 and placed the blocks to cover the overhang, but I still get a support.  Looks like the oblong hole's support is still extending beyond the face on one side. 

 

[GregValiant 1,489]

I think it's because of the Support Horizontal Expansion.

I've attached a project file.  The slice looks like this.

GV_DriveHolder.3mf

[saline 0]

Still having problems with the overhang.  I went and duplicated, I think, your settings.  It worked  on one side, but the other side still has the overhang.  It looks like the support in the elongated hole still extends out in one of the directions.  On one side it extends into the body, so no support.  On the other it extends outside the body, and I can't get rid of those supports.  Did I miss one of your settings?

CE3E3V2_DriveHolder.3mf

[GregValiant 1,489]

Did you open the 3mf as a Project File?  I used your printer with my settings.

This is your latest project file.  I don't see any extra supports.  It looks like I think you want it.

 

[saline 0]

That is what I want,  but here is what I get with the file I attached.  I went back in and opened it as a Project, just to make sure.  I then checked all the settings in the Support section, and they match yours.  Could the problem be in another group?

[saline 0]

Notice that the side with the support has the oblong hole support going to the outside, and the side without the support has the oblong hole's support going in.

[GregValiant 1,489]

I've never seen that before where a Project File slices differently like that.  You can see that I'm not getting any overhang on either side of the slot.

I've been thinking about putting in a feature request for "Everywhere except Build Plate" which might help in your case but the setting doesn't exist.  I suppose you could try setting the "Support Horizontal Expansion" to a small negative number.  Maybe that would tuck in that overhanging support you have there.  You might try rotating the model 90°.  Maybe it wouldn't overhang when aligned with the other axis.

 

I'm attaching a Gcode of my slice.  It won't solve the problem but you can print it.

CE3E3V2_DriveHolder (1).gcode

[saline 0]

Thanks. A minus value doesn't allow it to slice.  Weird things happen as I rotate it.  Attached are 2 examples.  The supports move from one hole to the other, and from the outside to the inside.

[saline 0]

Greg Valiant, your model worked perfectly.  Thanks.

[GregValiant 1,489]

Hold on now...Do you have Tree Supports enabled there?  Tree supports will always try to reach into any area they can get to.  I sliced with "Normal" supports and they don't try to get to places that aren't directly above.

[saline 0]

No.  Here are the settings of the project with respect to Normal supports.  I thought about that too.  It looks like a tree fill. But it seems to be happening to the elongated slots on the side it protrudes.  Is there a minimum width of a support?  In other words, I have a 2mm wall.  If a support is required to be at least 3 mm thick, it would go outside the structure and generate a wall.

[GregValiant 1,489]

Those supports look like they are round.  How about "Use Towers" in the Support Section?

 

No there is no minimum size.  I've seen some really skinny supports that were attempting to go up high on a model.  There was no way they were going to survive during the print.

There is a minimum size for support blockers though.  I think it's 5mm in the X and Y.  There is no minimum Z.

Edited April 16, 2023 by GregValiant

[saline 0]

That's it. Unchecking Use Towers did it.  Did you have that in your original profile checked?  I could have sworn I duplicated your profile.  Thanks.

[GregValiant 1,489]

I must have as our previews were different.