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Hello, If someone of you can help me with this (have look to the pictures) problem, I would be very happy.

I do not know where to change something in Cura to Stopp the filament flow earlier so that the edge 

not smear (grease) like on the picture.

Thank you for help.

David

Cura problem.jpg

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An easy thing to try is to cut your print temp back to say 195° - 197° C. It seems little, but I have had that make a world of difference and sometimes a bit of speed reduction to go with the temp. But not always. Retractions I am not that expert about at all though, so that would require a much more experienced person than myself.

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Well that doesn't look like much of an issue to me (sorry - don't want to say you are wrong or anything).  I mean I'd just cut that off after the print is done with a knife.

 

HOWEVER, there may indeed be something you can do.  But first - did you look at the layer view and do you know exactly what is happening?  Do you know if that is a retraction move?  Does it actually retract?  if it doesn't retract the solution might be to play with retraction settings.

 

More likely it *did* retract but the bottom layer has special considerations:

If you want your parts to stick well it's best to squish the bottom layer a bit.  So when you level with calibration card I believe the card is 0.08mm thick and so the printer sets the Z to 0.08mm there such that Z=0.0mm is touching the glass.

 

When you print, typically the bottom layer is always 0.3mm thick and it prints at z=0.3mm or 0.3mm off the glass.  But if you want your part to stick you should probably have the nozzle at 0.2mm off the glass. This makes the printer push much harder and makes the part stick really well.

 

But you get a tiny elephant foot like brim around the part.  Which is kind of sharp.  And kind of annoying.  However there is a great feature in cura called "first layer horizontal expansion".  If you set that to negative half of your nozzle diameter (typically -0.2) I found this corrects the micro-brim issue.

 

HOWEVER there is still one more issue - since you are overextruding all over the place on that bottom layer the pressure in the nozzle is unusually high and normal retraction is probably not enough getting you these little blobs.  I dont' have any good solution except to level slightly higher but then your part is likely to not stick and come loose during the print which is MUCH WORSE than a tiny little blob that can be easily cut off with a sharp knife.

 

On the other hand maybe this has nothing to do with retraction moves as I haven't seen the slice view of this part.

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Hi gr5,

thank you for the bulkier answer. The retraction works, but maby I can adjust it better than it is now. If ther is possibility to start the retraction earlier than it must work. The other thing what I will try now after your answer is to go a few higher with the first layer... at the moment I am with the first layer quite down.

So I do not have the problem that the part stick not really well, rather the opposite.

If I find the solution I wili post it here.

 

Thanks

David

 

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