Crazy bridges

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drivingon9
Posts: 5
Joined: Mon Jul 06, 2015 9:13 pm

Crazy bridges

Post by drivingon9 » Tue Aug 18, 2015 7:24 pm

Still fairly new-ish, but I've gone through a couple of spools worth of stuff so far (mostly simple things).. Trying some trickier prints and I seem to have issues whenever overhangs get too tricky.

So I've tried printing this a few times now : http://www.thingiverse.com/thing:925556
and it always looks great until I hit the part where it needs to do the 60mm bridges straight across.

Naively, I would guess that 60mm flat overhangs are the work of the devil, but reading comment, some people claim this is do-able on most printers. Mine ends up all super stringy/gooey and ending up melding the bridges to the screw.

Can the M2 handle this? If so, any tips/tricks? Slow bridge speeds and lots of cooling? Or do I need to sacrifice a goat or two to make it work?

Thanks!

jsc
Posts: 1864
Joined: Thu Apr 10, 2014 4:00 am

Re: Crazy bridges

Post by jsc » Tue Aug 18, 2015 7:51 pm

I've done longer spans than that with little problem. In PLA only, of course.

My personal recommendation for long bridges: slow speed (20 mm/s), 80-90% bridge extrusion multiplier to keep it stretched taut, lots and lots of cooling. Since I leave the fan on 100% for PLA at all times, that usually takes care of itself, but because I have a very powerful ducted fan, I've found that 100% fan can blow bridges around a little too much, so you may have to bring it down a little.

drivingon9
Posts: 5
Joined: Mon Jul 06, 2015 9:13 pm

Re: Crazy bridges

Post by drivingon9 » Tue Aug 18, 2015 8:55 pm

Thanks, jsc.. I had my bridge speed turned down, but not that low. I also didn't have my multiplier bumped down. I'll give both those a shot.

Thanks, again.

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Jules
Posts: 3144
Joined: Wed Jan 21, 2015 1:36 am

Re: Crazy bridges

Post by Jules » Tue Aug 18, 2015 9:04 pm

Yep! The M2 can handle it. (PLA not PETG.) I accidentally did some 112 mm bridges in PLA, just using my regular settings. (A lot faster than 20mm/s, no adjustments for bridging, and it might have dropped one thread. No sagging at all. I was quite impressed, even though i did not want a bridge there. :shock: )

If you can keep from sticking something into it while it's running - take the fan guard off of the bed fan. It jacks up the cooling exponentially, and it will make your bridges cool off faster. (Less sagging.) Might also want to take the temp down a few degrees.

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insta
Posts: 2000
Joined: Tue Sep 16, 2014 3:59 am

Re: Crazy bridges

Post by insta » Tue Aug 18, 2015 11:26 pm

drivingon9 wrote:Still fairly new-ish, but I've gone through a couple of spools worth of stuff so far (mostly simple things).. Trying some trickier prints and I seem to have issues whenever overhangs get too tricky.

So I've tried printing this a few times now : http://www.thingiverse.com/thing:925556
and it always looks great until I hit the part where it needs to do the 60mm bridges straight across.

Naively, I would guess that 60mm flat overhangs are the work of the devil, but reading comment, some people claim this is do-able on most printers. Mine ends up all super stringy/gooey and ending up melding the bridges to the screw.

Can the M2 handle this? If so, any tips/tricks? Slow bridge speeds and lots of cooling? Or do I need to sacrifice a goat or two to make it work?

Thanks!
I did a double-size one with 4mm of droop in the middle, with PLA.
Custom 3D printing for you or your business -- quote [at] pingring.org

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