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Lots of oozing with PETG  

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Galinette
(@galinette)
Eminent Member
Lots of oozing with PETG

Hi,

I started PETG recently and I experience quite a lot of oozing compared to PLA.

If I remove the extruded chunk and clean the nozzle when starting the print, after heating I have 3-4cm of extruded filament. And even if I quickly remove it before it moves, oozing during 7x7 calibration is enough to form a significant blob that makes my nozzle dirty at every print. That's quite frustrating.

Is there any simple way to avoid this?

Posted : 25/11/2022 6:01 pm
fuchsr
(@fuchsr)
Famed Member
RE: Lots of oozing with PETG

Adjust your startup gcode to go to 170 degrees for mesh bed leveling. Google for "bobstro note book startup gcode" to see a great walk-through. You'll still get some oozing though when the nozzle heats up to printing temperature, so be ready with your pliers or tweezers.

Posted : 26/11/2022 1:16 am
Netpackrat
(@netpackrat)
Reputable Member
RE: Lots of oozing with PETG

https://projects.ttlexceeded.com/3dprinting_prusaslicer_start_gcode_mk3.html

Posted : 26/11/2022 11:55 am
walt_3d
(@walt_3d)
Active Member
RE: Lots of oozing with PETG

I had the same issue. and suspect it was the reason that recently I had a large blob form that crashed a print. Not that I completely solved it, but I found that dialing back the nozzle temperatures by 10 degrees works reasonably well. I'm not one who is ready to mess around with g-code; maybe someday.

I've noticed since the crash mentioned above (and subsequent cleanup per this site), that the filament tends to stick somewhat to the outside of the nozzle. This happens on longer prints of small parts, and sometimes causes the print to fail toward the end. I've been cleaning off the nozzle between prints by running up the nozzle temp.  to 280 and cleaning with a folded over paper towel. Any suggestions on how to solve this issue? Thanks much

Posted : 26/11/2022 4:41 pm
AnnieR
(@annier)
Estimable Member
RE: Lots of oozing with PETG

Yeah, PETG oozes more than PLA. It always seems to drop off right after the print starts. 

Posted : 26/11/2022 6:30 pm
fuchsr
(@fuchsr)
Famed Member
RE: Lots of oozing with PETG

'm not one who is ready to mess around with g-code; maybe someday.

No need to dig into g-code and modify it. All it takes is go to Printer Settings→Custom G-code→Start G-code, edit a few lines per Bob's notebook instructions and save it as a new Printer profile. The key line is M109 S170. From now on, the printer will cool down to 170 degrees before mesh bed leveling so no more oozing during that process.

filament tends to stick somewhat to the outside of the nozzle.

PETG is notorious for curling up to the nozzle, heater block, the cat nearby. For one, as soon as purging after loading starts, I'm there waiting with tweezers to pull the emerging strand away from the nozzle. After mesh bed leveling, when it heats up to print temperature, again make sure you pick up any emerging filament. In general, with PETG it pays off to keep nozzle and heater block squeaky clean. I swap nozzles frequently, and when a nozzle come off the machine I use a heat gun and soft metal brush to clean any residues off. Also, nickel-coated copper nozzles and heater blocks tend to do better than brass, and with the tungsten carbide nozzles I'm using these days it also feels like less of an issue than before.

Posted : 26/11/2022 7:33 pm
walt_3d liked
walt_3d
(@walt_3d)
Active Member
RE: Lots of oozing with PETG

Thanks much! Excellent information. Will try the g-code mods. I've been removing the extra oozing after nozzle reaches print temp., but bed still heating. Also have been removing any filament sloughed off during mesh leveling. Figured those 'tricks' out early on. The nozzle and heater block tips are new to me, and I will definitely be getting some new nozzles. Also intrigued by the nickle-coated copper heater block.

Was wondering if anyone had ever tried using a plastic-injection-mold release agent on the nozzle and heater block? Just a wild thought 🙂

Thanks again.

 

Posted : 26/11/2022 8:21 pm
Artur5
(@artur5)
Estimable Member
RE:

Slice Engineering sells a plastic repellent paint for dealing with this issue. The product is applied with the brush of the vial’s top to the nozzle and the bottom of the heater block. I don’t know how effective this repellent can be, but certainly it seems awfully expensive at $15 for a minuscule 3 ml. flask.

This post was modified 2 months ago by Artur5
Posted : 26/11/2022 9:11 pm
jsw
 jsw
(@jsw)
Famed Member
RE: Lots of oozing with PETG

I've used it.  It helps a bit, but is not a cure-all.

Posted by: @artur5

Slice Engineering sells a plastic repellent paint for dealing with this issue. The product is applied with the brush of the vial’s top to the nozzle and the bottom of the heater block. I don’t know how effective this repellent can be, but certainly it seems awfully expensive at $15 for a minuscule 3 ml. flask.

 

Posted : 27/11/2022 1:54 am
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