1 Topic by Skyminer

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Topic: Bridging at .1 mm

Now that I've got all of my other kinks worked out, I'm trying to see what quality the SD3 is capable of printing. I've got fantastic prints coming off at .1mm, with the exception of bridging.

I've tried the default settings, have tried reducing the speed to 20%, and increased the bridging multiplier to 1.25. I'm not sure the changes in RH actually did anything.  The head certainly doesn't slow down where it should be bridging, and it looks to me like there's just not enough filament coming out at this resolution to make the jump.

Basically, I see the head get to where the edge is, travel over the edge at normal speed with no filament connecting, and filament starts flowing out in space.

Is there anything I can do to either slow things down, or cause it to over extrude AT&T he edge to give it something to connect to?  Or is it simply that Slicr isn't detecting the bridge properly and not coding for it?

2 Reply by accusedmonk (edited by accusedmonk 2014-03-22 06:28:16)

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Re: Bridging at .1 mm

Short version:
Try lowering the bridge flow ratio, speed it up for bridging, and a fan helps immensely to cool the plastic just enough to keep its shape after extrusion. 

Long version:
I'm basically in the same boat you are at the moment, where I have most everything dialed in fairly well at .1mm except for the bridging.

Were you changing it to 20% overall print speed, or just the bridging speed?  The bridge flow ratio should be lowered to help the plastic stretch.  I just now looked at mine and it was still at 1.0

I've done extensive reading through a number of forums, especially this one.  Generally for bridging you are stretching the plastic across from point to point.  Instead of slowing it down you need to make it go faster, not a whole lot faster though.

As of right now in my .1mm setup, I print infill at 60mm/s, perimeters at 40mm/s, and bridging at 75mm/s.  I don't have a fan on my doodle yet unfortunately.  My first 2 layers of the bridge still droop on me most likely from not cooling and holding shape properly.

Bowden SD3, Rumba, E3D hotend, Mk5 with RtRyder changes, Direct drive Y axis and bearings, GT2 pulleys and braided fishing line, Lawsy linear bearing conversion, M3 Z screw.

3 Reply by ronsii

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Re: Bridging at .1 mm

another thing is temps... I know you think it is all dialed in but if you can dial it in with just a degree or three less it will help with bridging, there are also some polymers that just don't like bridges... well at least for me smile

4 Reply by Skyminer

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Re: Bridging at .1 mm

I'm wondering whether Slicr isn't coding the bridges or something. Even though I've set a different speed for bridges in RH, the head doesn't slow down at all during the bridged areas.  It just flies along at the same speed.

5 Reply by creiht

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Re: Bridging at .1 mm

The current stable release of slicer (.9.9) has a known issue where it doesn't follow the bridging settings for perimeters, and has caused me a few headaches.  Supposedly it is fixed in the latest 1.0 release candidates, but I haven't had a chance to try it yet.

6 Reply by ysb (edited by ysb 2014-03-25 16:23:25)

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Re: Bridging at .1 mm

creiht wrote:

The current stable release of slicer (.9.9) has a known issue where it doesn't follow the bridging settings for perimeters, and has caused me a few headaches.  Supposedly it is fixed in the latest 1.0 release candidates, but I haven't had a chance to try it yet.


use the 1.0.0RC3 .. it's very stable..

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