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PLA stringing

Posted by Arakon 
PLA stringing
December 07, 2014 09:19AM
I finally got my printer adjusted decently for ABS, only to run into issues again with PLA.
I get stringing.. bad too.
I tried:
Increasing print speed from 50mm/s to 80mm/s
Increasing and dropping temperature. All the way from 170° to 210°.
Increasing and lowering retract. 1mm to 4mm, 20mm/s to 50mm/s.
Lowering flow rate from 100% to now 96% (ended up with noticable gaps between lines in top layers).
None of it made any majorly visible difference. The strings are so strong, I can pull parts off the bed by just lifting another part nearby.
Also getting blobbing on layer change.
Mendel90, direct drive Jhead extruder. Sliced with cura (skeinforge had the same issues).

Any help?
Re: PLA stringing
December 07, 2014 09:22AM
increase retraction or retraction speed.

sorry- just reread ans saw that you tried that.
but that is the only way I know of to fix that issue.
Is it a new roll of filament?

Edited 1 time(s). Last edit at 12/07/2014 09:24AM by cat.farmer.
Re: PLA stringing
December 07, 2014 09:56AM
No, this is halfway used already. I don't believe I had this issue before.. this may be partially related to the parts I am printing, but even with more "normal" shaped prints, I get random strings hanging around.
Edit: I just tried printing it again with the parts very far apart.. still strings, just much longer ones connecting the parts.

Edited 1 time(s). Last edit at 12/07/2014 10:49AM by Arakon.
Re: PLA stringing
December 07, 2014 11:38AM
Okay, now it gets strange. I just sliced with simplify3d, and no stringing at all. The only thing I can think of is that simplify has a retract compensation setting when starting to extrude again, while cura seems to be missing that option?
Re: PLA stringing
December 07, 2014 09:53PM
I have significant stringing whenever I slice with Cura. I don't know what it is. I have basically the same settings in Cura that I do in Slic3r, but Cura strings constantly, and slic3r strings rarely. I've even examined the G code and can't find an obvious difference between the two slicers that would account for the difference in stringing.

The stringing and poor bridging are what are keeping me from making cura my first choice as slicer. I still use slic3r most of the time. I have no experience with simplify3d, and I basically stopped using skeinforge - only going to it for the odd trouble object that won't slice with other slicers.
Re: PLA stringing
December 08, 2014 12:11AM
Okay, at least that tells me my settings or filament aren't totally off.
Thank you.
Re: PLA stringing
January 11, 2015 05:28PM
I've used Cura a lot, then came back to Slic3r because of this, but after printing some fairly important prints I've decided to switch back to Cura. Why? with Slic3r layering was better (hadn't had so many oscilations) but it left a lot of holes in prints. Where circle met sharp edges and so on. However retraction there is controlable better than Cura. But I'm more willing to cut the strings away, then to have bad prints in general.
Btw, just read at Ultimakers forum, that newest Cura has retraction compensation, it primes the same amount it retracts. I don't know I I have the latest version, so I'll definately try. However it would be nice if the just added the setting where we could adjust how much to prime
Re: PLA stringing
January 11, 2015 05:33PM
I switch back and forth now.
Slic3r has a tendency to fill small areas with single lines.. i.e. if I have a 1.5mm wide piece, slic3r will usually create 4 or 5 parallel lines that don't touch well and get no top layer, whereas cura will draw two lines and use infill and top layer for the space in between. On the other hand, slic3r creates great top layers and has little to no stringing, while cura tends to produce rough top surfaces and string like crazy in some models.
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