Help with bridging

[dsnettleton]

I've been working on my Rostock Max for a couple weeks now, and I'm finally getting some really good prints out of it. The only issue I seem to be having is with bridges.
I've tried numerous calibration prints using http://www.thingiverse.com/thing:11387.
[img]http://ubuntuone.com/7TpyabQq8bxOIGS7algFRE[/img] [img]http://ubuntuone.com/6RYtiJdzrbS68LMtFU49XN[/img]
I have blobs, inconsistent bridging, and sagging in all cases. I've looked everywhere for information on solid, consistent bridge prints, but everyone seems to disagree on just about every point, so I figure it's a bit more model-specific. Should my bridges be faster, slower, or neither? I've heard all three. What other settings should I look at to get my bridges coming out right?

Thanks,
--D. Scott Nettleton

[Polygonhell]

There is no easy answer, if they are breaking you want slower and a higher extrusion width while bridging.
If they sag you want faster and a lower extrusion width.
Perhaps the best way to think about it is when the plastic leaves the nozzle it is stretched, the narrower the extrusion width the more it's stretched, the faster you print the more it's stretched.
You want to stretch it as much as you can without it breaking.

[dsnettleton]

Does the extrusion multiplier in the filament settings "stack" with the bridging multiplier, or is it ignored while bridging?
Using Slic3r 0.9.9.

--D. Scott Nettleton

[cassetti]

I believe the bridge flow ratio under advanced settings (sorry, looking at slic3r 0.9.5, don't have 0.9.9 on this computer, don't know if they changed it) is a multiplier. I think it uses the final extrusion multiplier, I don't think it's ignored, hence why it's set to 1 by default.

I haven't been too concerned about bridging, I typically try to rotate my models so they print with as little bridging as possible if I can help it. And with things like an Xacto knife and acetone vapor baths, you can really eliminate any bridge flaws after the print has completed.

[dsnettleton]

Bridging isn't usually that big a deal, but every once in a while, prints like http://www.thingiverse.com/thing:16085 show up. I can't put a penny in the bottle opener if my bridges sag. Believe me. I've tried.

[elqisqeyano]

Bridging isn't usually that big a deal, but every once in a while, prints like http://www.thingiverse.com/thing:16085 show up. I can't put a penny in the bottle opener if my bridges sag. Believe me. I've tried.

Try it with thin support, maybe that works?