Any wizard of ooze?

So the video is below, and we are watching PLA oozing a lot free air
Well, this has never happend so far. I took down the printhead, cleaned everything etc... extruder is well calibrated, also checked.
The printer is Lulzbot Taz3
Material PLA, good quality (still it is 3 months since I bought it, maybe I should have protected it somehow)
Hotend at 185 degrees celsius (recommended for this PLA)

ooze video

Any help and advice appreciated

As long as there is pressure in the hotend the filament will get pushed out. You have to retract to relieve the pressure.

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Quote
Srek
As long as there is pressure in the hotend the filament will get pushed out. You have to retract to relieve the pressure.

Have you seen the video? It is not the question of regulare oozing before print. This is way too much of it... something's wrong

At max only the amount of filament already in the heated area of the hotend can ooze out. Since PLA becomes very fluid when molten it can easily ooze. However the amount that is oozing out of the hotend in the video looks like a good deal more than should be molten at any one time, thus my assumption that there is still pressure on the filament.

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[www.bonkers.de]
[merlin-hotend.de]
[www.hackerspace-ffm.de]

empty

Edited 1 time(s). Last edit at 08/11/2014 10:03AM by t0bb.

Quote
Srek
At max only the amount of filament already in the heated area of the hotend can ooze out. Since PLA becomes very fluid when molten it can easily ooze. However the amount that is oozing out of the hotend in the video looks like a good deal more than should be molten at any one time, thus my assumption that there is still pressure on the filament.

Ok I probably misunderstood you because I did not understand what do you mean by pressure on the filament (apologies)
The Idler screw is too tight ? Or my stepper motor is applying the pressure? If you could explain a bit
thanks

Can you try to just retract the filament immediately after you stop printing? In worst case even by hand.
Check if this reduces or prevent the oozing. I would expect it to reduce the oozing quite a bit. If it does there is some elasticity in the way the filament is transported, i can't tell where it comes from since i don't know the Lulzbot and your specific setup. Chances are that you will not be able to reduce this elasticity, so implementing a bit of post g-code to retract the filament at the end of the print should do the trick.
If the retract does not reduce the oozing my only guess is that the hotend has a very huge melting zone. In that case you can't do much except to cool down the hotend as fast as possible after printing.

---

[www.bonkers.de]
[merlin-hotend.de]
[www.hackerspace-ffm.de]

Quote
Srek
Can you try to just retract the filament immediately after you stop printing? In worst case even by hand.
Check if this reduces or prevent the oozing. I would expect it to reduce the oozing quite a bit. If it does there is some elasticity in the way the filament is transported, i can't tell where it comes from since i don't know the Lulzbot and your specific setup. Chances are that you will not be able to reduce this elasticity, so implementing a bit of post g-code to retract the filament at the end of the print should do the trick.
If the retract does not reduce the oozing my only guess is that the hotend has a very huge melting zone. In that case you can't do much except to cool down the hotend as fast as possible after printing.

you were right about the retraction fixing it after print.

The thing is, this Budaschnozzle 2.0 was working perfect up until now. This same PLA (also from lulzbot) was working perfectly last time. Then I had some prints done in ABS, and after a month I put on this PLA again, and this started happening

This hotend usually doesn't have oozing issue. The printer is fairly new, I got it 2-3 months ago
So if this thing occurred now after 2 months of usage, it must be something I did. Is it possible to damage something inside the hotend, while pulling the filament out of it?

Hm. Odd that it wasn't doing it as bad before. My first best guess would be a fault in your thermistor. It may be a cheap one that was damaged with higher ABS temps. Maybe the PTFE was damaged by the higher heat and the heat is reaching further up the filament. A note: PLA expands when it heats, that's why all metal hotends need active cooling, especially for PLA. Maybe a combination of the two. That's actually my first look at the Budaschnozzle. It's more expensive than the E3D v6; I've heard nothing but good about the v6 but I have heard some bad about the BS [pun fully intended]. That doesn't make sense to me why the BS is so popular when there is cheaper and better. Of course, to note again, that was my first real look at the BS, so I'm probably just missing something. Tradition maybe?

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Realizer- One who realizes dreams by making them a reality either by possibility or by completion. Also creating or renewing hopes of dreams.
"keep in mind, even the best printer can not print with the best filament if the user is the problem." -Ohmarinus

I wouldn't suggest anything different from MrDoctorDIV. The two issues that "long term" usage can bring on the machine are damages on the electronics or/and on the plastic parts, due to non adapted settings for theses parts.

Perhaps may I suggest things like cleaning extruder's teeth and checking idler pressure. These too are things that may have be altered with the usage of your printer, or while mounting another filament.

It fixed the issue a bit, to Retract by 5mm after the print. That relieved the pressure from inside the nozzle. All credits go to Srek
I'm guessing the problem is only partially solved though.
Will have to get to the bottom of this.

as far as extruder hygiene goes, I am very diligent, and always open up and clean everything. Idler pressure is fine as well
So first I should check the thermistor and that PTFE.
So should I look for the specs from support@lulzbot before I start opening things up... ?

I assume your hot-end shuts off immediately a print finishes?

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_______________________________________
Waitaki 3D Printer

Quote
waitaki
I assume your hot-end shuts off immediately a print finishes?

Well there is a Gcode to turn off hotend and bed temperature, if that is what you mean. There is no physical shutter
Lulzbot products are open source as any other DIY printer. Its just that they are pre- semi- assembled. Extruder is already calibrated and so on...

Just to update this thread,
My heater resistor stopped working soon after this problem started occurring. That must be related, because when I replaced the resistor, this massive oozing stopped. Could be that the temperatures were all wrong due to failing resistor