Slic3r bridges not connected to perimeters, but OK with Cura ?

Since posting the question I changed the Bridging flow ratio in Advanced back to default of 1 and it seems to have corrected the problem. I had it on 0.9 to create tighter bridges previously, but the result seems to have also changed the length of the bridge unexpectedly...

Martin
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I'm trying to replace Cura (the Creatbot custom version of it) with Slic3r software, because the fan control is much better thought out in Slic3r and should help me get better prints.
My problem with Slic3r is that when I slice an object like a 20x20mm hollow box test object and print it, it fails to bridge properly for the 'roof' of the closed box. The same test box when sliced with Cura prints fine, bridging is normal (or as good as Cura gets).
With Slic3r the strands of the bridge stop too short of the perimeter to adhere to it, so after the bridging layer completes the bridges just fall into the bottom of the box. The rest is very messy of course.
The top solid layers do seem to span the right amount and mesh into the perimeters properly, so whatever parameter I've screwed up only seems to effect bridging.

Clues anyone ?

Martin

Using Slic3r 1.2.9 Dev

Edited 4 time(s). Last edit at 06/25/2015 02:58AM by mr.sneezy.

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I notice that on my test boxes today that the top solid layers have a few places with gaps between filling passes across the top and the layer below it (where I can see it).
The bottom solid layer seem like they are about right during printing or even slightly over extruded. So not sure what I could change to fix the top ?

I have the exact same problem, the bridge doesn't adhere to the wall before it leaves it to start the bridge so everything just falls into the box.

Try increasing the bridging flow ratio value, it did help in my case. Not sure why it would but...

Both symptoms described are possibly due to under-extrusion.

Dave

Even though it works with other slicers fine ?

I experienced the similar problem while trying to print this model: [www.thingiverse.com] with 0.4 mm nozzle diameter and 0.2 mm layers.
This model has thin walls and default three vertical shell perimeters pushed bridge ends out of the walls. It is a bug in Slic3r I think: bridge ends minimal overlapping must have precedence over the vertical shell perimeters count.

Edited 2 time(s). Last edit at 07/20/2015 11:36AM by Evgeny.

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mr.sneezy
Try increasing the bridging flow ratio value, it did help in my case. Not sure why it would but...

Quote
dmould
Both symptoms described are possibly due to under-extrusion.

Dave

Is this still an issue? I want to run a lower flow ratio for bridges to stretch the extrudate across the gaps and reduce sagging - is there another setting for this?

There's also a new setting in the latest slic3r version "Infill/Perimeters Overlap" under "Advanced", increasing this may fix the problem - though I haven't tried it yet.

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geemoto
There's also a new setting in the latest slic3r version "Infill/Perimeters Overlap" under "Advanced", increasing this may fix the problem - though I haven't tried it yet.

Doesn't work for bridges conected to thin walls. "Vertical shells" option has precedence.