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So I am missing small sections of a layer when it prints, after a retraction for a layer change or a move, the extruder stops moving (no it isn't clicking or anything else. Just not moving). Which is fine for a few millimeters because the pressure inside the Bowden setup keeps pushing enough filament through. However, once that isn't enough it starts to make very thin lines with beads of plastic just barely holding things together. Basically this ends up as a good 2 cm or more at times of highly under extruded lines. This happens in the slowdown after the retraction when it is restarting. it simply doesn't move the extruder at all. The reason I know this is because I can see the extruder not moving, in that brief period. I know it is not the extruder clicking or anything else because I can disengage the extruder spring and push filament through manually during this time with no issues.

I am using Ideamaker currently because I like it.

I have looked at this Holes/ missing layers (after retraction) in 3d printed objects which is somewhat similar in appearance, but not in reason. enter image description here

Just a better image from the other side of the print

EDIT: So I figure it is some form of coasting that IdeaMaker has implemented for their Raise printers. I am going to try and reduce the length of the coaster attempt to convert my Bowden to a direct drive with titan extruder. I have the Titan already, but it has been giving me issues with not having enough power to push filament without ripping it to shreds. That's another thing I have to look at at some point when I have the time.

user3779413
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2 Answers2

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I know this might be a bit late, but I have been facing very similar issues with my printer (Anycubic Kossel Linear Plus).

In my case, I have managed to solve this problem by reducing retraction speed and retraction and extrusion max accelerations (if you are using Marlin, go to Control -> Motion and scroll down to A-max extruder and A-max rectract). I went down from 1800 to 1200 for extrusion and from 1400 to 1000 for retraction.

Also, I have played a bit with the stepstick, allowing a bit more of current for the extruder motor (normal XYZ are have a Vref~0.7 and the extruder it's set to 0.9). My understanding of the issue, is that the stepper motor cannot cope with the torque it is asked to deliver at sudden changes (high accelerations) and simply gets blocked until the acceleration is reduced. This can be due as well by too much friction (low printing temperature, clogged nozzle,... but it was not my case). Here there is a lot of information about the drivers.

0scar
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oscgonfer
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Try lowering your retraction settings further. I have had this issue before as well, but you need to experiment with your retraction settings in order to get it right. I would suggest placing 2 one cm blocks side by side and starting with a retraction of 2 mm and working your way up from there until you get the lowest stringiness with the least amount of under extrusion.

TECTEC3 Studios
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