Adhesion issue as print gains height and lower layers cool
I print with PETG on the Prusa smooth PEI sheet. I'm having an issue with adhesion on a particular model as it prints. One side of the print lifts up in the middle of the print and results in an uneven build. I am making an assumption that as the middle of the print cools during printing the plastic contracts and causes the bottom to lift off the bed. The model is unevenly weighted on one side and the side with more surface area stays put. In the image below the arrow points to where it lifts off the bed.
I don't generally have issues with PETG lifting off the bed but this particular model results in this issue more often than not.
So I'm looking for strategies for better adhesion. Will increasing the bed temperature to 85C (currently 75C) help with the contracting issue? I've also read that using hairspray to increase adhesion can work but I'd like to avoid something like that if possible.
RE: Adhesion issue as print gains height and lower layers cool
When printing PETg on the smooth sheet you should use an intermediate protective layer, such as stick glue, hairspray or similar. Otherwise you risk damaging the PEI surface because adhesion would be too strong.
Read Prusa's article for printing PETg :
https://help.prusa3d.com/article/petg_2059
RE: Adhesion issue as print gains height and lower layers cool
When printing PETg on the smooth sheet you should use an intermediate protective layer, such as stick glue, hairspray or similar. Otherwise you risk damaging the PEI surface because adhesion would be too strong.
Read Prusa's article for printing PETg :
https://help.prusa3d.com/article/petg_2059
Not be be contrary, but I print exclusively with PETG on 6 printers and they are running almost constantly, and I have never used anything other than the bare smooth PEI sheet. Generally speaking I do not have any issues with adhesion or getting filament stuck on the print bed. First layers stick well and I have no problems removing the prints from the bed. The issue I describe is ONLY printing this particular model.
RE: Adhesion issue as print gains height and lower layers cool
Try first layer at 85* bed temp and reduce to 75% of normal speed for first layer only.
Raise to 90* bed temp for the rest of the print.
If it sticks too well with no release agent used, don’t blame me…
Cheers
RE: Adhesion issue as print gains height and lower layers cool
Try first layer at 85* bed temp and reduce to 75% of normal speed for first layer only.
Raise to 90* bed temp for the rest of the print.
If it sticks too well with no release agent used, don’t blame me…
Cheers
Raising the bed temp to 85C throughout the print worked well. The print stayed connected to the bed but also came off easily after it cooled. I've only done one test print but I'm optimistic.
RE: Adhesion issue as print gains height and lower layers cool
Hey,
classic spot, but that doesnt look real bad.
2 things,
yea, hotter, 851rst/90
grab a 'helper disc' from the gallery, and slip it halfway under that corner.
that should make it fly.
look at how to print ASA info, that will graphically, and technically, explain what you are actually combating here in PETg which is generally much less suscepable to the phenomenom.
tldr
next step is to control the drafts you likely have around the machine, the part needs stable temps, so, an enclosure: which is in the slicer under skirts as'draftshield'
I print with PETG on the Prusa smooth PEI sheet. I'm having an issue with adhesion on a particular model as it prints. One side of the print lifts up in the middle of the print and results in an uneven build. I am making an assumption that as the middle of the print cools during printing the plastic contracts and causes the bottom to lift off the bed. The model is unevenly weighted on one side and the side with more surface area stays put. In the image below the arrow points to where it lifts off the bed.
I don't generally have issues with PETG lifting off the bed but this particular model results in this issue more often than not.
So I'm looking for strategies for better adhesion. Will increasing the bed temperature to 85C (currently 75C) help with the contracting issue? I've also read that using hairspray to increase adhesion can work but I'd like to avoid something like that if possible.