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First layer calibration help  

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wicax
(@wicax)
Active Member
First layer calibration help

Hello, 

I have been having some serious issues with getting the first layer right. Anytime I raise the live z it fails to stick at all. When I lower it, the edges start peeling up and the print catches. I tried replacing the nozzle, switches to brand new filament. I tried using acetone on the smooth pei sheet to get it app cleaned up but that didn't do much.

Please let me know if you have any other suggestions on how to fix that. 

Best Answer by Bob:

There are 2 main reasons for poor first layer, either your z-offset is too high, or your bed is dirty.  Even a clean looking bed can have a thin layer of oil on it.  Take it to the sink and scrub it well with a new sponge, dish detergent, and hot water.  Dry it well without touching it with your fingers.  Then do a first layer calibration and show us 2 pictures, a full bed like you did earlier then a closeup of the little rectangle at the end.

Cheers

-Bob

Posted : 20/02/2022 3:46 am
azDave
(@azdave)
New Member
RE: First layer calibration help

What filament material (PLA, PETG, etc) are you using?

Posted : 20/02/2022 4:37 am
wicax
(@wicax)
Active Member
Topic starter answered:
RE: First layer calibration help

Amazon basics pla. Not the best quality I know, but these first layer issues came on somewhat suddenly. 

Posted : 20/02/2022 5:06 am
azDave
(@azdave)
New Member
RE: First layer calibration help

As far as I can tell from the comments on the Amazon web site, Amazon Basics filament is basically just a rebranded version of the Overture brand, and that is at least decent quality.  I've used Overture filament in both PLA and PETG with good results, although PETG is more difficult to get homed in for settings.

I had lots of trouble with the same kind of globs your photo shows, although it was with PETG and not PLA.  I suspect the root causes might be similar, though.  In my case, I had to really fine tune the Live-Z setting, but once I did everything has been quite reliable.  I use the standard filament and printer profiles found in PrusaSlicer, and even though I've tried some temperature deviations just to check, I haven't seen a lot of impact.

Although I've seen comments that say acetone does not leave a residue, I believe that it does.  When I worked in the semiconductor industry we never used acetone as a final cleaner.  Soap and water with a thorough DI water rinse was always considered best, but I've had good luck with 91% isopropyl alcohol.

Sorry I can't offer something more definitive.

Posted : 20/02/2022 6:03 am
wicax
(@wicax)
Active Member
Topic starter answered:
RE: First layer calibration help

Thank you for the response. Helps to just know I might be on the right track, just weird it went from printing great to not being able to get anything to stick well.

Posted : 20/02/2022 7:17 am
Nessuno0505
(@nessuno0505)
Trusted Member
RE: First layer calibration help

Also try to do a cold pull.

And do not check first layer height with embedded Prusa test, it's a too small square to understand something IMHO. Try a 8x8 or 10x10 cm square with 1 layer height, it's a more reliable test to do first layer calibration.

Posted : 20/02/2022 11:38 am
ssill2 and wicax liked
Bob
 Bob
(@bob-2)
Reputable Member
RE: First layer calibration help

There are 2 main reasons for poor first layer, either your z-offset is too high, or your bed is dirty.  Even a clean looking bed can have a thin layer of oil on it.  Take it to the sink and scrub it well with a new sponge, dish detergent, and hot water.  Dry it well without touching it with your fingers.  Then do a first layer calibration and show us 2 pictures, a full bed like you did earlier then a closeup of the little rectangle at the end.

Cheers

-Bob

Prusa I3 Mk2 kit upgraded to Mk2.5s, Ender3 with many mods, Prusa Mini kit with Bondtech heat break, Prusa I3 Mk3s+ kit

Posted : 20/02/2022 2:17 pm
ssill2 liked
wicax
(@wicax)
Active Member
Topic starter answered:
RE: First layer calibration help

I will try that and get back to you with the results. One thing to clarify, when you say z offset is too high are you saying it is too close to the bed? Or are you saying the offset it too high meaning the nozzle is too far away.

 

Thank you!

Posted : 20/02/2022 6:54 pm
ssill2
(@ssill2)
Noble Member
RE: First layer calibration help

What nessuno and bob said.

 

100mm 1 layer(.2mm) square on a clean plate(good scrub with standard kitchen sponge and dawn) should and then do the square until it looks like.

https://forum.prusa3d.com/forum/original-prusa-i3-mk3s-mk3-assembly-and-first-prints-troubleshooting/life-adjust-z-my-way/

Note that the "right" z might be different for different sheets and/or materials.   The smooth plate is thicker than than the satin and textured plates and thus will require the z offset to be less negative by a lot.   Once you dial these numbers in you can safe steel sheet profiles in the printer:

https://help.prusa3d.com/en/article/steel-sheet-profiles_1955

 

I have things like "Spla" for the satin sheet + PLA and "SmPla" for Smooth sheet + PLA

Posted : 20/02/2022 7:00 pm
Bob
 Bob
(@bob-2)
Reputable Member
RE: First layer calibration help

When I say your z-offset is too high I mean it's too far away from the bed.  You may need to lower it.  That's why we need pictures of your first layer calibration.

Cheers

-Bob

Prusa I3 Mk2 kit upgraded to Mk2.5s, Ender3 with many mods, Prusa Mini kit with Bondtech heat break, Prusa I3 Mk3s+ kit

Posted : 20/02/2022 7:18 pm
azDave
(@azdave)
New Member
RE: First layer calibration help

 

The suggestion by ssill2 is exactly what I did, except that I did it with two layers and 100mm by 50mm to make sure I could also bond to the first layer with the z-offset I had selected.  I had been having all kinds of trouble with blobs using PETG, but that same setting had worked fine with PLA.  After I reduced the z-offset (raised the nozzle) from about -1.65 to -1.50 I now get great prints with my textured plate.

Posted : 20/02/2022 7:47 pm
ssill2
(@ssill2)
Noble Member
RE: First layer calibration help

I find that with PETG I have a different zOffset, and a separate "Spetg" profile for it.  The zOffset for PETG, for me, is always less negative than that of PLA.  TPU.  For me I've found the best success with PETG at higher temp, say 250, and maybe a .97'ish extrusion multiplier.  In particular printing things with supports, I find the higher temp absolutely necessary otherwise the petg is still too viscous and tends to pull the supports up and make a mess.   The steel sheet profiles help a lot.  You just have to do the square calibration for each material for a particular sheet.

Posted : 20/02/2022 9:06 pm
wicax
(@wicax)
Active Member
Topic starter answered:
RE: First layer calibration help

I tried cleaning with dish soap and that worked very well so far! I appreciate everyone's tips and suggestions, I am sure I will have to refer back in the future for more tips.

Posted : 21/02/2022 3:16 am
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