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PEI, Textured & PETG: concave pieces  

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Tonino
(@tonino)
Eminent Member
PEI, Textured & PETG: concave pieces

Hello guys, I really need your help!

I have a huge problem with piceces that are concave! It doesn't matter if it is PEI or textured sheet, the piece is always concave.

As you can see, the piece is always well attached on the bed nevertheless it is concave, I dont think it is "normal" but no one has a solution, what's wrong with this printer?

I use PETG Prusament with PS and standard profile.

Can anyone help me, please?

Thanks 

 

Posted : 08/02/2020 11:24 pm
rmm200
(@rmm200)
Noble Member
RE: PEI, Textured & PETG: concave pieces

Your part is warping; losing adhesion at the ends as it cools and the upper part shrinks. That part is pulling off the bed.

Try scrubbing your print bed with hot water and unscented dish detergent. Dry with a clean paper towel - and print. No IPA this time.

And use a substantial brim. It really helps adhesion.

Next step up: You might need an enclosure to maintain heat. Or even a tent made out of cardboard over the printer.

This post was modified 5 years ago by rmm200
Posted : 09/02/2020 5:01 pm
Tonino
(@tonino)
Eminent Member
Topic starter answered:
RE: PEI, Textured & PETG: concave pieces
  • Thanks. But where do you see the loosing of adhesion?

I had to use a tool to remove it.... 

 

Thanks

Posted : 09/02/2020 6:11 pm
rmm200
(@rmm200)
Noble Member
RE: PEI, Textured & PETG: concave pieces

Only at the ends...

Look at your two parts touching. You can see the last inch rising up.

Posted : 09/02/2020 6:44 pm
Tonino
(@tonino)
Eminent Member
Topic starter answered:
RE: PEI, Textured & PETG: concave pieces

They rise up but there were very well sticked on the bed! 

Posted : 09/02/2020 8:15 pm
rmm200
(@rmm200)
Noble Member
RE: PEI, Textured & PETG: concave pieces

Can we get a closeup picture of the bottom of one of the parts?

I find it hard to believe that the part could be pulling the print sheet up off the magnets - but stranger things have happened.

It would be good to hear another opinion or two about now...

 

Posted : 09/02/2020 8:19 pm
Neophyl
(@neophyl)
Illustrious Member
RE: PEI, Textured & PETG: concave pieces

Actually I believe that easily.  I dont do a lot of PETG printing but a friend asked me to print some electronics box housings that took up nearly the whole bed.  When finished the box was well stuck to the sheet but it had lifted the corners of the steel sheet up away from the magnets.  There was around 4-5mm of lift and as it was a translucent petg I could see where the layers in the corners were further compressed down from the .2 I was printing at.  Luckily he could still use the parts even with the curve.

If I had to do it again I would try binder clips at the from and back to help hold the sheet down, although I'm not sure if anything would help given the contraction of the material.

Posted : 10/02/2020 7:19 am
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