When printer is sitting preheated, PLA oozes out from nozzle
 
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josh.r3
(@josh-r3)
Active Member
When printer is sitting preheated, PLA oozes out from nozzle

When printer is sitting preheated, PLA oozes out from nozzle for about 3 minutes or so. When I try to print anything it is messing up as there's random places that will ooze out a little PLA and mess up the print. I'm no longer able to print anything as the first layer is always having a little extra oozed filament, which sometimes if it's too high, get stuck on the tip and is dragged around. Prior to this issue I had a couple of times where I had an ooze blob accumulate in which I had to heat up the extruder and slowly peel it off. I've tried replacing the tip. I've also rerun xyz calibration multiple times and I've adjusted the z height to what seems like the prefect height.

Help would be appreciated so I can get printing again. I was 1/2 through printing Settlers of Catan. ;(

Posted : 03/09/2018 2:30 am
bobstro
(@bobstro)
Illustrious Member
Re: When printer is sitting preheated, PLA oozes out from nozzle

What filament and temps are you using? If it's ooze from the nozzle, you can try slightly cooler temps. Is it only ooze that occurs before the print that's a problem? If so, you can modify the startup gcode so the nozzle doesn't heat up completely before the bed leveling. You have it wait until right before you start printing to finish heating up. You can also lay down a thicker prime line to pull away any ooze.

From your description, it sounds like you might be suffering from an accumulation of crud on your hotend and nozzle as well. Have you tried removing the fan shroud, raising Z to max and giving it a clean with a soft brass wire brush? Be careful around the thermistor and heat cartridge wires.

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 : 03/09/2018 6:10 am
josh.r3
(@josh-r3)
Active Member
Topic starter answered:
Re: When printer is sitting preheated, PLA oozes out from nozzle


What filament and temps are you using? If it's ooze from the nozzle, you can try slightly cooler temps. Is it only ooze that occurs before the print that's a problem? If so, you can modify the startup gcode so the nozzle doesn't heat up completely before the bed leveling. You have it wait until right before you start printing to finish heating up. You can also lay down a thicker prime line to pull away any ooze.

From your description, it sounds like you might be suffering from an accumulation of crud on your hotend and nozzle as well. Have you tried removing the fan shroud, raising Z to max and giving it a clean with a soft brass wire brush? Be careful around the thermistor and heat cartridge wires.

I'm using PLA. Using the same default preheat settings that I've been using for a year which is 215. Ooze before the print and during the printing. I haven't changed any settings for anything since this issue started occurring so the only thing I can think of is a hardware issue of some sort, and I already tried replacing the tip. I did try lowering the temperature to 195 and 205, but the PLA wasn't sticking as well to the bed.

Posted : 03/09/2018 10:56 pm
Steve
(@steve-3)
Estimable Member
Re: When printer is sitting preheated, PLA oozes out from nozzle

Are you using a different filament brand? I notice that a few of them have different amounts of oozing. Some leave tiny blobs at all 9 calibration locations. Others only leave 1 or 2 blobs.

Steve

Posted : 04/09/2018 12:59 am
josh.r3
(@josh-r3)
Active Member
Topic starter answered:
Re: When printer is sitting preheated, PLA oozes out from nozzle


Are you using a different filament brand? I notice that a few of them have different amounts of oozing. Some leave tiny blobs at all 9 calibration locations. Others only leave 1 or 2 blobs.

Steve

I've used the brand before oozing problem and also another brand. All of them ooze now.

Posted : 05/09/2018 4:50 am
alexander.s27
(@alexander-s27)
Estimable Member
Re: When printer is sitting preheated, PLA oozes out from nozzle

Oozing for some minutes while sitting preheated at print temparature for the given filament
I would consider as quite normal, nothing to worry about.
If this ozzing -as you are describing- is such heavy, even while printing and even messing up the 1st layer
hints that your temperature seems to be way to high for your filament.
Given you made no changes both in mechanics and your slicer settings
I would guess a wrong (to low) temperature reading at the hot end.
Reason could be a loose/shifted thermistor or damaged thermistor cable.
Measure your hot-end temps with an external (infrared) thermometer and check if the printers reading is reasonable.
Also try to print the templates from the prusa-delivered sd-card or download some pre-sliced from this here website
and try to print those...

Posted : 05/09/2018 1:06 pm
Nikolai
(@nikolai)
Noble Member
Re: When printer is sitting preheated, PLA oozes out from nozzle

Oozing doesn't bother me as-well. It's kind of normal depending on the filament.
Anyway some people are adjusting their start g-code to avoid this. Following idea for PLA:
1. Preheat nozzle to 170C
2. Run G80 height measurement
3. Preheat nozzle to 210C
4. proceed with printing

The only downside is that you have to clean the nozzle before/during step 1. Otherwise you will ram kind of cold plastic into your bed and might damage it.

Often linked posts:
Going small with MMU2
Real Multi Material
My prints on Instagram

Posted : 12/09/2018 2:27 am
josh.r3
(@josh-r3)
Active Member
Topic starter answered:
Re: When printer is sitting preheated, PLA oozes out from nozzle

Here's what my prints look like now since the issues started happening.
https://photos.app.goo.gl/8gSJmU6DFfapnvRV9

And here's what it used to look like.
https://photos.app.goo.gl/6hzGaVXWUCye7wNU7

Would replacing the tube inside the extruder just above the nozzle help I wonder. I recently ran the temperature and PINDA calibrations but that didn't seem to help.

Prusa support emailed me back and all they said was oozing is normal. I'll email them back with the pictures to see what they say.

Posted : 17/09/2018 3:48 am
bobstro
(@bobstro)
Illustrious Member
Re: When printer is sitting preheated, PLA oozes out from nozzle


[...] Prusa support emailed me back and all they said was oozing is normal. I'll email them back with the pictures to see what they say.
Looking at those pics, the oozing is a red herring. You've got stringing issues. Have you changed our slicer settings? Is that the exact same filament in both pics?

In general, to deal with stringiness, you can look at lowering temps, increasing travel speeds and adjusting retraction.

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 : 17/09/2018 6:05 am
alexander.s27
(@alexander-s27)
Estimable Member
Re: When printer is sitting preheated, PLA oozes out from nozzle


Looking at those pics, the oozing is a red herring. You've got stringing issues. ....
In general, to deal with stringiness, you can look at lowering temps, increasing travel speeds and adjusting retraction.

Seems my attempt (ours both) to help went kind of unnoticed by the TO.....

Above I wrote....
Given you made no changes both in mechanics and your slicer settings
I would guess a wrong (to low) temperature reading at the hot end.
Reason could be a loose/shifted thermistor or damaged thermistor cable.
Measure your hot-end temps with an external (infrared) thermometer and check if the printers reading is reasonable.
Also try to print the templates from the prusa-delivered sd-card or download some pre-sliced from this here website
and try to print those...

In my opinion those small items as hidden behind the above external links are not suitable for bugfixing.
I guess the Prusa guys will not say anything to the pictures, why should they?
Same goes for the attempted PINDA calibration and the thought about changing the PTFE tube.
That has nothing to do with heavy ooze or stringing.

Sudden massive ooze hints on to high extruder temps for above stated reasons.
Also, maybe the filament gathered to much moisture which in some cases could lead to stringing.
(I never experienced that, living in a moderate region and storing it in boxes with the silica-satchels)
Would explain, why all the TOs filaments are leaking.

Posted : 17/09/2018 12:14 pm
josh.r3
(@josh-r3)
Active Member
Topic starter answered:
Re: When printer is sitting preheated, PLA oozes out from nozzle



Looking at those pics, the oozing is a red herring. You've got stringing issues. ....
In general, to deal with stringiness, you can look at lowering temps, increasing travel speeds and adjusting retraction.

Seems my attempt (ours both) to help went kind of unnoticed by the TO.....

Above I wrote....
Given you made no changes both in mechanics and your slicer settings
I would guess a wrong (to low) temperature reading at the hot end.
Reason could be a loose/shifted thermistor or damaged thermistor cable.
Measure your hot-end temps with an external (infrared) thermometer and check if the printers reading is reasonable.
Also try to print the templates from the prusa-delivered sd-card or download some pre-sliced from this here website
and try to print those...

In my opinion those small items as hidden behind the above external links are not suitable for bugfixing.
I guess the Prusa guys will not say anything to the pictures, why should they?
Same goes for the attempted PINDA calibration and the thought about changing the PTFE tube.
That has nothing to do with heavy ooze or stringing.

Sudden massive ooze hints on to high extruder temps for above stated reasons.
Also, maybe the filament gathered to much moisture which in some cases could lead to stringing.
(I never experienced that, living in a moderate region and storing it in boxes with the silica-satchels)
Would explain, why all the TOs filaments are leaking.

Thanks. I will try out your suggestions. I tried to get a temperature reading with my infrared gun. Either it's broken or something's wrong with the extruder tip because the temperature reading is not even over 100 even when the Prusa display says over 200. I have a new sealed box of PLA I can try as well.

I emailed Prusa support with the pictures and here's what they said:
These problems may also appear when the filament takes in some moisture or when, for example, the nozzle is not properly tightened. You may also try to increase retractions in Slic3r. Disassembling the hotend is also an option, if you will do that, I recommend adding a good amount of thermal paste on the heatbreak.

Posted : 21/09/2018 5:57 am
josh.r3
(@josh-r3)
Active Member
Topic starter answered:
Re: When printer is sitting preheated, PLA oozes out from nozzle

I tried multiple suggestions and looks like I may have a hardware issue. Everything was going well after multiple test prints of a 1 layer square. I tightened the extruder tip a little as I noticed a little melted filament coming from around it when it is screwed in. I adjusted the temp to 205. When I tried to print something more subtantial after the first few layers I notice it started looking like it was oozing. I looked at the side and noticed this.
https://photos.app.goo.gl/YxBg3Zzvs7QnHwdN6
Looks like it's leaking from the inside between the metal rectangle the wires plug into and the inside extruder with the heat sink. Not sure how to get it to not do this aside from taking it all apart and pulling it from the machine to see if it is damaged.

Posted : 23/09/2018 1:23 am
alexander.s27
(@alexander-s27)
Estimable Member
Re: When printer is sitting preheated, PLA oozes out from nozzle

https://help.prusa3d.com/l/en/article/fJa7GxLSG6-changing-or-replacing-nozzle

Posted : 23/09/2018 7:05 am
josh.r3
(@josh-r3)
Active Member
Topic starter answered:
Re: When printer is sitting preheated, PLA oozes out from nozzle

I finally got around to removing the extruder from the plastic case or whatever. The extruder was loose so I tightened it to the heat exhanger. When I put everything back together no more leaks. Bad new now is that when I do a first layer test print (about 5"x5") the filament randomly decides to not feed anymore and the motor with the feeder on it fails as grabbing the filament to pull it down. If I pull it out, cut the spot where it stopped feeding because there are grooves in the filament where it failed to feed down, then load it back in, it will usually finish the print off. If I try to print it again it will fail in a different spot in regards to the feeding the filament down. This is so frustrating. Just when I thought my issues were over.

Posted : 29/11/2018 2:13 am
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