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Bridging Issues, I'm stumped.  

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Boney
(@boney)
Active Member
Bridging Issues, I'm stumped.

I had some issues with my printers last year so I put them down and decided to get back to building a profile from scratch.

I had a first layer issue I've worked thru so now I am working on a bridge test. I have printed 7 bridge tests with various bridge flow ratios to see where the sweet spot is, and every time I print this I am getting this strand of filament that doesn't bridge properly.

I've found my bridging sags the least with a bridge flow ratio between 0.65-0.7, which from what I've been reading may be too low. The stringing also has me wondering if there maybe another setting that needs tweaking that will fix both the sag and this incomplete bridging.

As no one has replied to any posts I've made yet, I'm experimenting with decreasing bridging fan speeds. 80% was no avail. I don't think I'm printing too hot. I'm using Prusament, hot-end 210c, bed 60c. BUT WHAT DO I KNOW!?

Please help!

Posted : 08/02/2022 7:40 pm
Boney
(@boney)
Active Member
Topic starter answered:
RE:

Could this have anything to do with my issue? I hope this isn't a dumb question.

I have noticed in slicer, the bridging starts ever so slightly after an external perimeter move. You can see this in the attached picture. I have no idea, and I'm just wondering what it could be, because this is present no mater what I set the bridge flow ratio to. Perhaps there is a setting unknown to me that bridges this GAP... like SLICE GAP CLOSING RADIUS?!?! AM I ON TO SOMETHING????

This post was modified 2 years ago by Boney
Posted : 08/02/2022 8:18 pm
fabiobollinger
(@fabiobollinger)
Active Member
RE: Bridging Issues, I'm stumped.

Can you tell which strand is not connecting? Is it the same one as the blue one in the slicer? From the pictures it looks like a couple strands away from the edge. Is the picture from the bottom surface or the top?

Posted : 08/02/2022 10:21 pm
Boney
(@boney)
Active Member
Topic starter answered:
RE: Bridging Issues, I'm stumped.

It is 100% the blue overhang that's not connecting. Here's another pic of the bottom view of the overhang perimeters. It's like one of the strands disconnects or doesn't ever connect to the wall of the spiral. I've been printing these bad boys all day. Lowered temps. Lowered fan speeds. I just recently lowered my bridge speed from 30mm/s to 25mm/s and that *may* have helped. I honestly cant tell anymore. I don't know what to do...

Posted : 09/02/2022 12:50 am
Boney
(@boney)
Active Member
Topic starter answered:
RE:

Attached is the .stl of the bridging test.

Just to clarify, the picture of the print I took is from the bottom view.

This post was modified 2 years ago by Boney
Posted : 09/02/2022 1:49 am
fabiobollinger
(@fabiobollinger)
Active Member
RE: Bridging Issues, I'm stumped.

Would you mind sharing the project file? You'll have to ZIP it and upload the ZIP folder here.

The dark blue is actually not a bridge pass, it's an "overhang" pass. Check the Support Material settings - Overhang threshold. Try 0° for auto detection if not already.

My assumption is that the corner is rounded, or beveled, so the slicer is trying to print those overhangs using the bridge as a support, but the angle is too shallow so it doesn't stick.

I can have a look at the project file and try to find other settings that affect this

Posted : 09/02/2022 6:28 pm
Boney
(@boney)
Active Member
Topic starter answered:
RE: Bridging Issues, I'm stumped.

Ahhh I'm a noob at the forum. Here we are.

I suspect you are on to something with the overhang threshold. I apologize for using the wrong term. Still learning it all, even though I've had these things for over a year now.

I did just find that the steel sheet I was using is warped in the center. I made another post about that. I don't figure that would have anything to do with this issue though. Just thought I would mention. I've been able to print successful prints on this printer since posting this. In fact, after finding my sheet was warped, my first layers have been on point! Still don't understand the warping though.

Posted : 13/02/2022 7:28 pm
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