Is 44 seconds of filament output after 3Dprint completed normal/safe?
 
Notifications
Clear all

Is 44 seconds of filament output after 3Dprint completed normal/safe?  

  RSS
HermannSW
(@hermannsw)
Estimable Member
Is 44 seconds of filament output after 3Dprint completed normal/safe?

I created a small borescope holder for my new 3Dprinter:
https://forum.prusa3d.com/forum/user-mods-octoprint-enclosures-nozzles/simple-nozzle-camera-borescope-holder-for-prusa-mini/#post-582007

Today I took a 1:48min video of a 3Dprint of a very small part (more skirt than part) after initial auto bed leveling:
https://forum.prusa3d.com/forum/user-mods-octoprint-enclosures-nozzles/simple-nozzle-camera-borescope-holder-for-prusa-mini/#post-582439

Part is complete at 1:04min, the last 44 seconds document the steady output of filament despite ended.

Is this normal/safe?
Can the time filament gets output after end of 3Dprint be reduced?

Posted : 18/02/2022 8:44 pm
mrstoned
(@mrstoned)
Reputable Member
RE: Is 44 seconds of filament output after 3Dprint completed normal/safe?

Yes, some degree of oozing will happen while the hotend cools down and the remainning plastig inside become solid again.

The amount will vary with the type of filament.

PLA melts at around 180+c while PETG or ABS takes 200ish to soften up.

Prusa Mini+ kit. BondTech extruder. FW 5.1.2
Prusa MK3S+ kit. Stock. FW 3.11.0
Prusa MK3S+, used. Stock. FW 3.13.3

Posted : 18/02/2022 9:04 pm
HermannSW
(@hermannsw)
Estimable Member
Topic starter answered:
RE: Is 44 seconds of filament output after 3Dprint completed normal/safe?

Thanks for confirming that oozing is expected,

I did create new borescope holder that allows nozzle to be in camera focus, and created a new video of auto bed leveling:
https://forum.prusa3d.com/forum/user-mods-octoprint-enclosures-nozzles/simple-nozzle-camera-borescope-holder-for-prusa-mini/#post-582628

PLA melts at around 180+c 

I did print with PLA, but Octoprint does heat nozzle to 170°C only before auto bed leveling. Only after auto leveling, nozzle gets heated to 210°C. As you can see in video I recorded, oozing happened again, but at 170°C already (I started with clean nozzle). And the oozed blue part moves around during complete auto bed leveling.

I am not sure whether stop at 170°C before auto bed leveling is an Octoprint or Prusa MINI+ thing, found no setting for 170°C in Octoprint preferences.

Posted : 19/02/2022 12:45 am
mrstoned
(@mrstoned)
Reputable Member
RE:

edit; The 170c thingie is a prusa setting to prevent (most) oozing when heating nozzle, heatbed, probing for autolevel.

 

All different makers of filaments have slightly different characteristics.

For example, the current Primaselect ABS i use, i print at around 250-255c, and after finish the temp drops of quite fast down to around 220ish and it only oozes around 5-10mm from the nozzle.

For PLA, printing at around 210-220 it takes longer for the nozzle to cool down to below the melting temp of the filament.

Melting temp (or when the filament goes soft enough to expand due to heating) is different then printing temp as the filament is in a more liquid state then a sof/melted state that is enough for oozing slightly.

 

I'm not a material expert by any stretch, but this is the thermodynamic properties i picked up from watching youtube and reading papers online.

 

Another example is candlewax, it's soft at around 52-55c, starts melting to liquid at around 58c+

Prusa Mini+ kit. BondTech extruder. FW 5.1.2
Prusa MK3S+ kit. Stock. FW 3.11.0
Prusa MK3S+, used. Stock. FW 3.13.3

Posted : 19/02/2022 6:26 am
HermannSW
(@hermannsw)
Estimable Member
Topic starter answered:
RE:

Thanks for the information.
I think I found the reason why oozing happened at 170°C for my PLA 3Dprints yesterday — and I am guilty!

I did start several 3Dprints, and cancled them after auto bed leveling, because I was interested in video of that.
Obviously some kind of pressure built up from filament intended to be printed on initial line.
Today I did cut away the oozing after print and recorded video starting with end phase of auto bed leveling.
As you can see there is not any oozing during auto bed leveling.
Only after 15s when heating up to 210°C oozing starts, and that oozing gets left behind at 35s while printing side line:

 

P.S:
I uploaded part of that video separately, showing last full layer and then 3Dprinting "into the air" with 70° overhang, just nice:

Posted : 19/02/2022 10:45 am
Share: