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Can't get a good first layer  

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PreZ
 PreZ
(@prez)
Active Member
Can't get a good first layer

I am printing first time with Prusament PET-G.

I am using the textured bed, which I JUST opened (ie. never printed on before with any other material).

I have tried

  • Default settings for Prusament PETG with nothing on the bed (what I tried first!)
  • Increasing and decreasing bed temp (from 85 to 90 or 80)
  • Increasing the extrusion temp (from 240 to 250) for first layer
  • Adding 50% cooling on the first layer (normally it disables cooling for 3 layers)
  • Windex
  • Glue Stick

But I can't get a good layer.  Even the z-levelling doesn't adhere (the corners/short edge detach and are short-circuited).

Any ideas what I can do to get that fabled perfect first layer with PET-G?

 

I have been printing great prints with PLA on the smooth PEI coated steel bed.  But this is my first time printing PET-G and using this textured bed.

 

 

I have been looking at other posts, but they seem to be trying to print PET-G on the steel sheet, but seem to imply 'just use the textured sheet and MAGIC!' ... not so much.

I wanted to change the world, but God wouldn't give me the source code....
Posted : 17/04/2020 7:02 pm
Neophyl
(@neophyl)
Famed Member
RE: Can't get a good first layer

Just looking at that picture your Live Z value is no where near low enough.  I take it from your post that you have another sheet, have you adjusted the live z value for this sheet ?  All sheets (even of the same type) will vary slightly but the powder coated sheets are thinner than the smooth sheets.

Even once you have the z dialled in for a powder coated sheet many many people have initial adhesion issues, even with petg until they clean the sheet initially with dish soap such as dawn/fairy and lots of hot water to rinse.  Even though Prusa specifically says not to with powder coated as the steel can rust, if you thoroughly dry it and then bake it on your print bed at 90 degrees for awhile (both sides) you will be ok.  

Posted : 17/04/2020 7:55 pm
PreZ
 PreZ
(@prez)
Active Member
Topic starter answered:
RE: Can't get a good first layer

Thanks neophyl!  That was the piece of information I was lacking!

 

I didn't want to touch the live Z value due to the big red warning on here: https://help.prusa3d.com/en/article/pei-print-surface-preparation_2203

 

However, after adjusting it, the print quality is getting significantly better (I am still dialing it in a bit).  I only got the printer this week, so I am not enough of an expert to recognize Z-level problems.  I am also surprised that the difference in width between the smooth and textured sheets is so dramatic (but it obviously is).

I wanted to change the world, but God wouldn't give me the source code....
Posted : 17/04/2020 8:24 pm
JoanTabb
(@joantabb)
Moderator
RE: Can't get a good first layer

Try this method!

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

regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK...
Posted : 17/04/2020 8:38 pm
Peter M
(@peter-m)
Noble Member
RE: Can't get a good first layer

Posted : 18/04/2020 10:39 am
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