#Clumping or bad adherence?

24 messages · Page 1 of 1 (latest)

fiery breach
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Hello everyone! I'm having an issue on a specific print that kinda bugs me.
Here's the deal: Either I print with the standard 60° bed temperature given to me by my cura gcode file and then my first layer starts adhering perfectly - but since the piece is kinda large - but by the time it has deposited a few strands, there's no adherence at all anymore and it goes baaaaaaaad, nothing sticking to the bed anymore.
Either I crank up the bed temperature to 70-80 in my gcode, then there is no issue adherence but I end up with some weird clumping as you can see on image.
Now for this specific piece, there are maaaaany more layers on top on that one, so much that in the end I don't notice any issue on the final printing (except the bottom of the piece that I'll clearly need to use sandpaper on (second picture).
As a footnote, there is also some warping on one corner of the final print.
Also, on that specific print, the first layer seems very...thin. I use a black PLA filament, and yet it is almost translucent.
For the gcode I ended up using the on from Cura with the Alfawise U20 non-plus profile (default settings). I print on an Alfawise U20 plus, with standard PLA. I have a custom fan duct.
Now I have spent quite some time on trying to make this print work, so I've done quite a few things (hopefully I won't forget something):

  • Total z offset check and balancing;
  • Multiple bed leveling (paper method, as I don't have auto bed leveling) on five points - both with cold and preheated bed;
  • Trying many different start/end gcodes;
  • Cleaning thoroughly both bed and extruder with isopropanol;
  • Preheating before prints (additionnaly to the gcode preheating);
  • Using brim/raft (the original print already uses a brim regardless), failed so I don't use one on that print.

The end result is serviceable (it's an organizer for a boardgame so the quality is not that important), but I'm a bit disappointed by the result, and I fear it could happen on more complex prints. Thank you halp

20240707_162902.jpg 20240708_175426.jpg
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Additional information:
I don't have the standard bed anymore, it is a simple piece of glass now.

mellow dawn
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that glass seems to be very warped, it has dips in it, and yeah the clumping is from heat, with glass and pla you really don't need heat, try it without heat and some gluestick if bare clean glass doesn't adhere very well for you

viral panther
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Did you try replacing the nozzle?

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Also take a look at the extruder hobbed gear teeth and look for any cracks on the extruder somewhere

fiery breach
fiery breach
viral panther
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When the nozzle wears down over time it causes inconsistent printing issues, you might have overcompensated for something like first layer flow

fiery breach
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hmmmmmm....

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I haven't changed my nozzle like, ever. But then if it'd be that, I should notice the same inconsistencies randomly present with every print right?

fiery breach
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I did however notice that my nozzle clogs a lot lately, when it rarely ever did

viral panther
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if you print regularly, you should replace it after a couple months

blazing osprey
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Check the mesh

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nvm

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My bad

blazing osprey
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Nozzel seems to close to the bed at points

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Lower at the others

fiery breach
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thanks to other people inputs, we established last week that my glass bed seems completely uneven

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so it doesn't help

viral panther
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How was it established?

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You didn't confirm it

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Printing on a raft can negate it a bit

fiery breach
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Yeah I was planning on doing raft next

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We did a few tests, but the most useful I think is that by rotating the bed I obtain very different results. Right now if I put it a specific side of the bed (the most even I guess) I do not get that clumping. I get a shitload of warping which I imagine is coming from me tweaking the bed temp from 60 to 70 (or as you said, could be the extruder)