Oozing during mesh bed leveling  

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Jeroen3
(@jeroen3)
Active Member

When printing PETG, the nozzle starts oozing during heat-up. I can clean it before print, but when the printer performs mesh bed leveling, some has oozed out again and this time wrapped around the nozzle.

This is a problem, since this blob will release somewhere along the first 10 layers, and mess up the print.

Maybe the slicer can insert some step right before the intro line and raise the extruder for the user to clean the nozzle?

Otherwise, maybe perform all of the bed heating, homing and leveling, before heating the nozzle and printing the intro line?

Best Answer by bobstro:

The easiest way to eliminate such oozing is to do a 2-step nozzle warmup.

  1. While waiting for the bed to heat up, only heat the nozzle up to a safe "no ooze" temp. I use 160C with PETG and PLA with good success. Technically, you could simply wait until later to do any nozzle warmup, but I find having the filament soft before homing avoids driving any hardened ooze into the PEI print surface at homing.
  2. Then do your mesh bed leveling.
  3. Only once you've homed and are ready to print, do the final nozzle warmup to actual printing temps.

I've got my documented gcode here that shows all of this in practice if you'd like to review it here.

Original Prusa i3 MK3S...
Posted : 25/05/2019 9:04 pm
bobstro
(@bobstro)
Illustrious Member

The easiest way to eliminate such oozing is to do a 2-step nozzle warmup.

  1. While waiting for the bed to heat up, only heat the nozzle up to a safe "no ooze" temp. I use 160C with PETG and PLA with good success. Technically, you could simply wait until later to do any nozzle warmup, but I find having the filament soft before homing avoids driving any hardened ooze into the PEI print surface at homing.
  2. Then do your mesh bed leveling.
  3. Only once you've homed and are ready to print, do the final nozzle warmup to actual printing temps.

I've got my documented gcode here that shows all of this in practice if you'd like to review it here.

This post was modified 1 year ago by bobstro
My notes and disclaimers on 3D printing and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan...
Posted : 25/05/2019 9:32 pm
Jeroen3 liked
Jeroen3
(@jeroen3)
Active Member

That works very well. Thank you!

Original Prusa i3 MK3S...
Posted : 27/05/2019 6:15 pm
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