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Hi,

I noticed a weird problem with retractions in Cura generated gcode. Every other time I print a gcode file, there is a failed retract blob on the first layer. For example, if I slice a part and print it, it might fail retract on some part of the first layer. So I stop the print and re-print, and it doesn't do it. Then I re-print again once the part is finished and it blobs again. It consistently does it EVERY OTHER TIME. It's driving me crazy because the blobs ruin the prints but I can't figure out why it's doing it. The identical gcode causes every-other-time problems with no changes. It reminds me of Einstein's insanity quote.


I switched to Kisslicer for a print (which I haven't used for around a year) and it retracts fine, but too often. I'm getting at least 50 retracts every minute with Kisslicer, and I'm using the old Steve's extruder with a 30mm retract so it's loud.

I noticed a similar retract problem with Slicer last year, which is why I switched to Cura. It just makes no sense to me that retract fails are dependent on gcode from different slicing programs, but identical gcode can consistently cause failures even if it looks the same. Has anyone else had problems like this?

That is very odd. By failed retract you mean it smears too much filament in one spot? I've noticed sometimes on my first layer, even when I have "retract while combing" plugin enabled, there will be one line of a comb printed, kinda like you mention. I haven't noticed if it was every second time precisely but I couldn't rule that out. Cura here as well. Wait... combing shouldn't happen "over nothing" so I think this is the exact issue you're having. Failed retracts on moves... right? Does yours cause a straight line printed where there shouldn't be one?

Not quite, the effector picks up a few millimeters and move across a gap, but it retracts before picking up and the cold end vibrates during the retract. Then when it gets to the next spot, it un-retracts and pushes out the extra plastic into a blob. Without stopping the print, the blob can knock my magnetic arm setup off.