Strange Printing Defect! Please Help,
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@phaedrux diagonals, yes, circles no.
With the nimble what could actually cause that eccentricity?
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I imagine that would be the tolerance stacking they mentioned in that copy and paste above.
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Doesn't look like an eccentric gear or loose bearings/case/hob shaft due to the tight spacing. I had an undersized hobb shaft and the effect was more spread out. Looks more to me like cable/stepper side problem. What is your minimum cable radius? Can you detect any slapping of the cable against the sheath? Re lube, I use 20K diff lube and it works fine. Others I have heard using 10K to 100K.
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Oh, another thing to check is that the end of the cable is all the way down inside the worm gear.
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@phaedrux said in Strange Printing Defect! Please Help,:
Very low extruder jerk and very high pressure advance can lead to some odd side effects. I'm not super familiar with the nimble, but I realize they recommend low jerk due to the worm gear drive?
Honestly the low jerk / acceleration was the biggest hurdle for me. I almost gave up but I hunted for low inertia / fast steppers. I found that 3.6 degree parallel disc magnet steppers from Portescap (P430 258 005 01 with the coils wired parallel) allow for some serious extruder acceleration and jerk. As a test I have tried up to 100mm/s retraction without any problem even with the 30 to 1 gearing. Be sitting down if you look that stepper up though. Fortunately I got them used for less than 10% new price.
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Spoke quickly to Brian from Zesty Tech over email. He suggested a few things which have improved the quality but still not quite there 100%. May be having a call with him tomorrow.
One thing I have mentioned to him though, the worm gear seems much looser in the bearing on one end, I am not sure if this is intentional but may be an issue?
If anyone can suggest anything to improve this result further I am all ears....
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@damianm reducing the extruder acceleration to 1000 did wonders to be honest. I will have to check a few other slicer settings and esteps to see if I can improve on the finish I am currently getting.
It's good but now as good as I got from it on my previous printer.
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@syko_symatic That looks like it might be related to the loose fit at one end of the worm to me. It is similar to what I got when a bearing was getting worn out.
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Jammed some paper in between the looser end on the worm gear and the bearing and it seems to have helped. I have ordered a new nimble (as they have a slightly improved version now) so maybe I need to get a replacement worm gear? I will have to measure it first and see if it was manufactured incorrectly.
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@Syko_Symatic Thank You!
