Thanks for the suggestions, I will try them out and let you know the results.
I know that retraction is working to some extent, as I can see the material shoot back up the tube, and the feeder at the back grips the filament very tightly and there doesn't seem to be any play in it at all.
One more piece of information that might or might not be useful is that the printer head is making a lot more noise than the first one. It is hard to explain the sound, but it is kind or a vibrating sound mixed with a hum, that sounds a bit like chewbacca... I have tightened every screw in the head, but the sound remains. If I pull the feeder tube towards myself while it is printing, the sound stops, but starts again as soon as I release the pressure. The sound only starts several minutes into a print.
I don't think that this is connected to the retraction issue, because that problem has been there from the beginning, but the sound is relatively new, but it is yet another issue plaguing this machine...
Thanks again for all the help.
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gr5 2,225
Hi guys - I'm late to this thread. Reading all the posts from the start I've slowly picked a theory that explains everything and is trivial to test for. But a little tricky to explain. Plus the theory could be wrong. Anyway the super quick resolution would be to increase retraction from 4.5 to maybe 6.5. But there is a better solution...
the problem definitely seems to be related to retraction. It's doing *some* retraction but not enough. I also think it could be partly temperature - the temp sensors can vary by +/- 10C but you lowered temp by 20C and although that helped it was not enough. So here's my theory.
If you make sure there is no pressure on the filament (standard situation when printer finishes a print and is on or off). Then lift up on the bowden at both the print head and at the feeder and see if there is some play. It's easy to put the bowden tube back in such that there is play - even with that little horse shoe clip installed properly. To remove all play you have to know how the bowden holder thing works - but first realize that for every mm of play you have at either end of the bowden you need to increase retraction by the same amount.
To reduce play (only if it moves up and down by at least a half mm) realize first that there are 4 metal blades in the bowden holder. Loosen the 4 long thumb screws 3 times (about 1.5 full rotations) so that there is about .5 to 1mm play in the entire print head. Then remove the horse shoe clip, then push down on the bowden holder ring. Only move the bowden in and out of the head while that is being pressed down by the other hand. Now push down on the bowden firmly and also lift the bowden holder ring. Then tighten the 4 thumb screws so that the head is tight. Now the bowden should be tight enough that it doesn't move even without the horse shoe clip. Reattach the horse shoe clip anyway (you don't want to lose it I suppose).
If I'm wrong about play in the bowden at the head or at the feeder then alternatively simply increase your retraction distance by 1mm at a time and test again at 5.5mm, 6.5mm and 7.5mm.
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gr5 2,225
foehnstrum's theory has merit also. Something wrong with retraction.
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