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Trying to understand retraction
#1
Hey folks,

I got some new filament recently, and it seems to behave a little differently than the XYZ ABS filament. I'm having better success extruding at 235 C, whereas I always ran the XYZ ABS at 220 C. When I tried running my new filament that cool, the extruder would click quite frequently, and I heard a lot of popping. I have neither of those problems at the higher temperature.

My new problem though, I think is related to retraction. I'm getting a lot of blobs on my prints now, and my extruder is making some weird noises when it retracts filament. I'm including a link to a youtube video to show what I mean. If you look closely, you can see the nozzle lift up a bit on retraction, and you can hear the springs squeaking a bit. It seems like the extruder stepper is pulling hard enough on the filament to actually lift the nozzle up, since it's only held in place by a spring mechanism. http://youtu.be/PJ_XyHnaMi8

I also tried a print with no retraction at all. I think I got a similar amount of blobs, but they were more "robust", in that they didn't scrape off quite as easily. I also got some stringing, of course, but it wasn't terrible.

I am using Cura as my slicer, with 40 mm/s retraction speed, 4.5 mm retraction distance, minimum travel 1.5 mm, and minimal extrusion before retracting 0.02 mm. How can I change these settings to get better results? Would slower retraction or a shorter distance help? Should I extrude at a different temperature?

With XYZ filament I never had the blobbing problems, but if I recall correctly, the extruder "squeaking" and lifting up on retraction MIGHT have started when I switched to repetier firmware. I'm hoping this isn't a filament problem and that I can tweak some settings to get better results. Thanks for the advice!
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#2
When I used Cura my retractation was 3mm( 4.5 was definitly to much) and now in S3D, I use the pre-defined one for Davinci : 2mm at 30mm/s, and so far so good.
EDIT: XYZ ABS and common ABS do not have same composition, so it is normal that extruding temperature change, it is same behavior between others filament brand names.
I get used to print at 230/110 for first layers then slowly change until 230/90
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#3
Thanks so much luc! I used 2mm at 30 mm/s and this print turned out beautifully!
Any thoughts on why the nozzle is lifting with the retractions? that still happens with those lower slower settings.
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#4
well when it do a lot of retractations, I can hear it sometimes like tac... tac ...tac, but it seems normal as I have another printer which do same noise, it i ts the noise of the wheel changing direction quickly and it is not extruder clicking, but nothing else, so cannot say if it is what you call nozzle lifting
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