Constant PLA oozing at any temperature  

RE: Constant PLA oozing at any temperature

I re-ran the entire calibration wizard on the printer, which I am assuming includes the PID calibration.

My printer has printed i'd say for ~3 weeks straight. ( 24/7, with small breaks in between, but almost 3 weeks , average of 20 hours a day ). I do have a new nozzle coming, I just fear it may not be the solution.

I have tried multiple different filaments. Moreso, this filament had no issues prior, and then suddenly started leaking like in the video I posted.

All filaments at 190C replicate this issue.

RE: Constant PLA oozing at any temperature

Posted by: jeremy.s25

I do have a nozzle on the way. Some people mentioned the nozzle may be the issue. Is it truly possible the nozzle would cause this odd leak?

It depends on just how worn the nozzle is. Check out the CNC Kitchen video at about 10:18. In an extreme case (which could happen with less than a spool of abrasive material) the nozzle bore could be so large that there's very little back-pressure. You'll see the same effect with larger nozzles. TBH, at this point, I'd swap it and see. We can speculate all day long, but a 5 minute swap will yield some useful data.

RE: Constant PLA oozing at any temperature

Well, as I said, I have a nozzle on the way, but thanks to the USA holiday weekend it's not here until Monday, so I was just trying anything else I can do with what I have now. I'll have one on monday, but hopefully this resolves it. I miss my printer. : ( 

RE: Constant PLA oozing at any temperature

Posted by: jeremy.s25

Well, as I said, I have a nozzle on the way, but thanks to the USA holiday weekend it's not here until Monday, so I was just trying anything else I can do with what I have now. I'll have one on monday, but hopefully this resolves it. I miss my printer. : ( 

Well, that limits options. Just to be clear: You're certain the filament is oozing out the bore of the nozzle, and not from above where the nozzle screws into the heater block, correct?

Have you tried:

1. Removing, cleaning and re-installing the existing nozzle?
2. Lowering temps 5-10C?
3. PID calibration?

Otherwise, I'm afraid you'll just have to drink beer and eat hotdogs until the post arrives.

Did you by any change do the extruder calibration routine (manually extrude 100mm of filament, measure, etc.)?

Have you tried using another slicer? Cura had a release recently that defaulted to 3mm nozzle size and caused all kinds of havoc until people figure out what was going on. Definitely try the default Prusa profiles.

RE: Constant PLA oozing at any temperature

Oozing is normal,

hot weather, enclosure, brand filament.

pla is not oozing, i change to different brand, its oozing a lot.

is your, tube-heatbrake-nozzle, build how it should be, look for several manuals, on how to.

I would do nothing, just clean it, and if it prints good, stay off everything, and print till repair is needed.

If you repair it-service it, you could brake it, so do not do it.

RE: Constant PLA oozing at any temperature

I overnighted a new nozzle. Unfortunately it did not resolve the problem.

This is what is occuring at 190F. It will eventually leave a blob somewhere. Basically, if the nozzle is over 190, it will constantly extrude. It's not a minor problem, and does not print good. I cannot complete any print because of excessive overextrusion.

The problem isn't the nozzle and now I feel lost.

I have tried PID calibration 2x.

I have tried different filaments.

I have tried lowering temps to about 175, where it stops oozing, but then it has issues sticking to the bed / coming out consistently.

My printer worked fine for several weeks with no extrusion, even at 215C, with several models of PLA, and I noticed stringing start to happen over time, and now it is consistently oozing and making the printer unusable.

RE: Constant PLA oozing at any temperature

The video shows ooze, but it is symptomatic of too high a nozzle temperature and filament that has oils or other contaminants on it.  You aren't using a filament oiler are you?

I once had a spool of filament that was packed by someone who had applied hand lotion just before handling the spool. The entire first layer of filament was worthless; and once I got past that layer things started working normally again.

And - as an FYI - the extruder isn't instant start-stop capable.  There are strain and hydraulic effects at play and even though you stop E-Axis motion there is still tension on the filament that takes a bit to release.  You might be having over expectations on how the extruder normally behaves.

ps: this has zero to do with the nozzle ... if the new nozzle "fixes" it, then it was an assembly issue, not the nozzle.

RE: Constant PLA oozing at any temperature

I am not using a filament oiler. I am a brand new prusa user, and a novice to 3d printing.

I am using a filament roll I just opened yesterday. I live in Texas, USA, so the environment is pretty dry. I am not using any humidifiers or anything in my home.

RE: Constant PLA oozing at any temperature

Filament oozes when it is hot; you might want to just start printing and not worry about it.  The video didn't look like any unreasonable ooze. The filament in my printer right now will do just about the same. Extrude 100 mm - stop - and it will ooze for a while after.  Perfectly normal.

Heck, ask anyone about gnats during mesh level and everyone will have a story to tell. That's why many of us have added gcode to preheat only to 160-185c for mesh level. Nozzles ooze as the filament heats up, and mesh level leaves tracks (49 small gnat-like spots left on the bed where the nozzle is measuring).

And if you are new, then the last thing you want to do is replace the nozzle.  A mistake there will be a challenge for you to fix.

RE: Constant PLA oozing at any temperature

Question: when you opened the spool, did you touch the filament?  You have to touch the end you insert into the extruder when loading, but did you hold the spool in a way your hands touched the filament on the spool?  If yes, then you left oils on the filament.  Finger prints and PLA are not compatible. You need to be very careful handling the filament and the PEI sheet. One fingerprint will ruin your day.

RE: Constant PLA oozing at any temperature

Posted by: jeremy.s25

[...] I am a brand new prusa user, and a novice to 3d printing.

Have you done any non-Prusa calibration routines by any chance? I've read of cases where somebody followed instructions for another printer and wound up with a mess. I'm asking because you mention "excessive overextrusion". Are you having other over-extrusion issues along with the nozzle oozing?

Any firmware updates or other changes?

If you're game, a factory reset is one way to ensure all the settings are reset. You'll have to go through the entire XYZ calibration, and will want to repeat the PID and temperature (PINDA) calibration steps.

I wouldn't worry about a bit of ooze, but you didn't have the problem originally, so something's changed.

RE: Constant PLA oozing at any temperature

And - looking back at that first image; there are signs of adhesion problems: a perimeter that didn't stick.  These will wind up on the nozzle and come off later as a blob, like that stringy mess coming up from the bottom.  The yellow highlights the inner perimeter than didn't stick to the bed.

RE: Constant PLA oozing at any temperature

Oozing in the beginning off print is normal,

start the print, clean the nozzle wen it gets hot, then  the print starts.

Yes it still can ooze wen doing calibration, try to clean this.

is the printing after calibration this okay?

Oozing also can come from the extruder if there is a gab somewhere, is the tube,  heatbrake and nozzle build how it should be?

Look under the extruder , do you see filament coming out between the parts?

Lower temperature, a little!

And let the nozzle wait longer heated, so it can ooze out the filament a little bit.

Enclosure and hot temps?

3d printing is will never be load model and start the printing, you will always have to adjust things, and read a lot of forums to learn.

RE: Constant PLA oozing at any temperature

Posted by: jeremy.s25

I'm following the instructions at Prusa's website, 

https://help.prusa3d.com/article/lnbcnhg76k-cold-pull

Okay ... makes sense now. It sounded like you were pulling filament out at 180c.   

PID calibration helps with temp control: reducing overshoots and recovery.  E.g., setting 210, the uncalibrated nozzle might hit 225 before stopping the heat ramp (it takes time for the heater cartridge heat to get to the thermistor cartridge). PID adjusts the timing based on a measured thermal response, and gives a better prediction of when to turn off the heater before the temps overshoot.   A factory reset deletes the old stored information, you might be running on defaults.  

RE: Constant PLA oozing at any temperature

I have not done any non-prusa calibration routines.

It's not just oozing during preheat that is the problem. It's constant oozing that is the problem.

This applies to all prints. I even got another PLA roll today and didn't even touch it.

Here is the issue.

There is so much oozing printing, eventually, when it moves to a new location ( finishing a section as pictured up top ) , it will leave a glob. That glob will destroy the print.

I've almost got it under control by lowering the flow to 85, but when I lower the flow so much the quality of my first layer suffers intensely, as pictured here.

I attempted to re-run PID calibration twice.

Filament is not coming out of the parts. It is only coming out of the nozzle.

I cannot lower the temps much more than 190 or the printer will be not usable for the reason I bought it for(making durable costume pieces) The exact same brand, exact same roll of PLA was printing just fine last week, but this week it is oozing a ton and leaving globs, and no matter how many I buy, or what kind of PLA I use, the oozing is still super intense, eventually too much will come out of the nozzle and leave a blob somewhere that destroys the print, even if I turn the temps and flow way down, but if I do, my print quality suffers intensely.

RE: Constant PLA oozing at any temperature

Posted by: jeremy.s25

I have not done any non-prusa calibration routines.

OK, worth confirming.

It's not just oozing during preheat that is the problem. It's constant oozing that is the problem. [...] There is so much oozing printing, eventually, when it moves to a new location ( finishing a section as pictured up top ) , it will leave a glob. That glob will destroy the print.

I can see that from these pictures. You're essentially getting large amounts of heavy stringing as the nozzle is moved from one part to the next.

I've almost got it under control by lowering the flow to 85, but when I lower the flow so much the quality of my first layer suffers intensely, as pictured here.

I know you must be frustrated. The fact that it clears up at 85% flow is encouraging, even if not a viable fix. Some of these are just checklist items, so be patient if we make what sound like repetitive suggestions.

I don't have any explanation of why it "went bad", but it sounds like it's consistently bad, so hopefully fixable. I'm inclined to think it's a setting at this point.

I attempted to re-run PID calibration twice.

Good. This plus your previous observation at PLA flow stopping as expected give some confidence to the accuracy of your thermistor. 

Filament is not coming out of the parts. It is only coming out of the nozzle.

Good. Another slew of problems we can eliminate.

I cannot lower the temps much more than 190 or the printer will be not usable for the reason I bought it for(making durable costume pieces) The exact same brand, exact same roll of PLA was printing just fine last week, but this week it is oozing a ton and leaving globs, and no matter how many I buy, or what kind of PLA I use, the oozing is still super intense, eventually too much will come out of the nozzle and leave a blob somewhere that destroys the print, even if I turn the temps and flow way down, but if I do, my print quality suffers intensely.

This is more throwing ideas and thoughts out there in the hopes it'll trigger a memory or idea...

• Have you tried printing the pre-generated Prusa gcode samples. Do they exhibit the same behavior?
• Have you tried slicing with another slicer? Any difference?
• Some settings are retained in the printer between power offs. Flow rate is one, whether set in the slicer or dialed in with the front knob. I'm going to assume you've done numerous power cycles at this point though.
• Have you done a factory reset?

Also, to avoid chasing two different problems:

• The oozing from the nozzle at the start of a print is a nuisance but normal. A good prime line routine should catch any pre-print oozing.
• The stringing and mess on the print may be loose filament accumulation, not ooze.

As Tim notes, bed adhesion is crucial. While you've got a bit of ooze, some of what you're seeing looks like filament accumulating (dislodging from the bed) and bunching up, generally making a mess as it goes. I used to suffer from much the same problem starting out. I dreaded printing support or even skirts because they'd dislodge and drag across the print.

How do thing look as you get to higher layers? Is that stuff dragging about limited to the 1st layer? In my case, the 1st layer might be a disaster, but if it all held together well enough to get to higher layers, I could get some decent prints.

Could you upload:

• The output gcode from a small print? I'd like to take a look to see if there's something obvious in the gcode.
• A 3MF project file (you'll have to zip it to upload here) with your part and settings?

If nothing else, we can try using the same part, settings and software to verify we get different results. This will be more data to give tech support.

Again, the fact that it's so predictable and reproducible is encouraging. Stick with it!

RE: Constant PLA oozing at any temperature

I also see the feature of insufficient filament idler tension.  Up may want to tighten the tension screw a turn or two. This has a large effect on retraction and wipe efficiency.

But -- did you do ANYTHING to the printer between last weeks good print and this weeks bad print?  I mean anything?  Move the thing, move the table it is on, dust it, clean it, oil it, flash new firmware, etc.   Perhaps a roommate played with it? 

RE: Constant PLA oozing at any temperature

And back to ooze.  If the extruder motor isn't turning, new filament can't get into the hot zone to melt. That zone is 2 mm x 12 mm, approximately. And it isn't gas tight, so vaporous byproducts generally don't force the chamber to purge (moisture will escape the melt in the middle of the melt zone, and cause some pressure to ooze, but it will stop after a few seconds). Gravity is about all that pulls plastic out a static nozzle. And there is only so much melted plastic ... so it can't ooze continuously when just sitting there.  If it does ooze continuously, then the E-motor is spinning or the filament is somehow free to fall into the extruder (loose Bondtech tension). 

For grins, check the Bondtech idler gear. 

There is an axle shaft that sometimes falls out of place. The shaft must engage each ear of the door equally. Per this sketch.  It usually results in clicking and under extrusion, but your problem is weird enough, it's worth checking out.

RE: Constant PLA oozing at any temperature

I was able to complete the test frog print, btu the results aren't so great.

Here's an overhead

There's also quite a few globs on the face

Also some on the legs

I think I got lucky with that one. I attempted to re-print the spool i'm trying to print again, and eventually this happened.

https://imgur.com/a/3f6DD5T

This was going absolutely fine for a while but suddenly inconsistent extrusion, it looks like?

Here is a gcode of hte spool i'm trying to print, but I don't think the problem is native to the gcode, since what happened to the frog.

https://mega.nz/#!sodyCQrQ !OzMK_CjsVzGGUg2BiMAARYJIlnQmWOcPjOsNVEz-LeI

RE: Constant PLA oozing at any temperature

Things to note, immediately after printing this after the tree frog, I tried printing this

the nozzle jammed and I had to basically push the filament down through while the nozzle was hot to get filament to comeo ut again