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PETG Filament build up around the Nozzle  

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McBeary
(@mcbeary)
Active Member
PETG Filament build up around the Nozzle

Hey guys,

After printing a lot of PLA on my Mk4 I wanted to try PETG. I’m not new to printing and my old Ender is tuned in, but Troubleshooting can be a pain.

I woke up to the printer being stopped, due to a fan failure. There was some PETG in the Fan an a big blob of PETG around the hotend. I raised the temperature in steps from 235 to 250 and the part cooling fan from 30 to 50% now. But could it be, that I have to permanently adjust the z-offset in PrusaSlicer for PETG to reduce or even eliminate Filament being stuck to the nozzle? Is there a setting in the Filament section of the slicer, maybe add something in a custom gcode there? PETG doesn’t like to be squeezed to the bed, but since the distance should be the same with the new loadcell sensor everytime, there has to be some setting we can adjust permanently for Special Filament types, right?

Posted : 09/05/2023 6:21 am
FoxRun3D
(@foxrun3d)
Famed Member
RE:

I've noticed similar issues with my XL. Prints perfectly with PLA but PETG seems to result in the nozzle slightly dragging in the first layer and accumulating filament. Not much but enough to have to clean the nozzle between prints to avoid clumps of filament dropping on the subsequent prints.

There's a filament override section in Prusaslicer under Filament Settings but it only affects retraction.

You could theoretically use the Z-offset parameter in Printer Settings>>General>>Size and coordinates, but that's not filament specific so you'd have to create a new printer profile just for PETG, and at least for me with several physical printers and nozzle sizes configured, this would make my printer menu explode.

Curious what others say.

 

This post was modified 1 year ago by

Formerly known on this forum as @fuchsr -- until all hell broke loose with the forum software...

Posted : 09/05/2023 11:08 am
McBeary liked
McBeary
(@mcbeary)
Active Member
Topic starter answered:
RE: PETG Filament build up around the Nozzle

After reprinting I found at least the error for the massive build up. One part lost adhesion, got stuck on the nozzle and I stopped it. First time it happened it must have caused a layer shift and the hotend got covered in Filament.

But still, the curling PETG around the nozzle and the blobs that accumulate, fall of and lay around are still a little mystery. Flow is calibrated, it may be even slightly lower than it should (if you trust the two wall cube). I’ll test some more, reduced parts on the sheet and used some hairspray. PETG can be a pain in the a**.

Posted : 09/05/2023 11:14 am
Jeremy
(@jeremy-3)
Trusted Member
RE: PETG Filament build up around the Nozzle

 

Posted by: @mcbeary

After reprinting I found at least the error for the massive build up. One part lost adhesion, got stuck on the nozzle and I stopped it. First time it happened it must have caused a layer shift and the hotend got covered in Filament.

But still, the curling PETG around the nozzle and the blobs that accumulate, fall of and lay around are still a little mystery. Flow is calibrated, it may be even slightly lower than it should (if you trust the two wall cube). I’ll test some more, reduced parts on the sheet and used some hairspray. PETG can be a pain in the a**.

PETG is notorious for blobbing and accumulating, it can be tricky to find the right mix of settings to mitigate it.  I've started printing in ASA a lot of times when I would have used PETG in the past.  Not always possible based on the need of the part, but in many cases.

Posted : 09/05/2023 6:04 pm
MikeH and McBeary liked
McBeary
(@mcbeary)
Active Member
Topic starter answered:
RE: PETG Filament build up around the Nozzle

Sure. But I was under the assumption of out of the box printing. I’ll tune some more then 🤗

Posted : 09/05/2023 6:18 pm
Artur5
(@artur5)
Reputable Member
RE:

Yes, we all know that PETG can be a nasty customer more often than not.

Which brand of PETg and plate are you printing with ? (smooth, textured, satin.. ). Are you positive that the filament is perfectly dry ?. If you’re unsure, dry it. Don’t print very fast (specially infills ) and try lowering a few degrees the nozzle temperature, I see that you started using adhesive; that can help and it’s quasi mandatory on the smooth sheet.  Time ago I purchased a flask of plastic repellent paint and I apply it regularly on the nozzle. It doesn’t makes wonders, but helps a bit.

Anyway, depending on the brand, results can differ a lot. After trying several of them, nowadays my PETG of choice is Geeetech. I prefer it to Prusament, which tends to be more stringy and sticky, at least with my setup.

Posted : 09/05/2023 8:27 pm
McBeary liked
Jeremy
(@jeremy-3)
Trusted Member
RE: PETG Filament build up around the Nozzle

 

Posted by: @artur5

Yes, we all know that PETG can be a nasty customer more often than not.

Which brand of PETg and plate are you printing with ? (smooth, textured, satin.. ). Are you positive that the filament is perfectly dry ?. If you’re unsure, dry it. Don’t print very fast (specially infills ) and try lowering a few degrees the nozzle temperature, I see that you started using adhesive; that can help and it’s quasi mandatory on the smooth sheet.  Time ago I purchased a flask of plastic repellent paint and I apply it regularly on the nozzle. It doesn’t makes wonders, but helps a bit.

Anyway, depending on the brand, results can differ a lot. After trying several of them, nowadays my PETG of choice is Geeetech. I prefer it to Prusament, which tends to be more stringy and sticky, at least with my setup.

Agree with all of the above.  I find Polymaker also works really well for printability, adhesion, layering, and finish.

Posted : 09/05/2023 8:31 pm
McBeary
(@mcbeary)
Active Member
Topic starter answered:
RE: PETG Filament build up around the Nozzle

I use Filament PM. As far as I know, they do produce for Prusa. In this case, this one was the former Prusa Orange from 2018, although it’s more red.

After starting with PLA in the Mk4 (I mostly print PETG though), I switched to the textured sheet for PETG.

You maybe right regarding the speed, I didn’t change that in the PrusaSlicer, just the brand of filament. The roll used should be dry, I just opened it up. Speed maybe an issue, I’ll try and test print something at different speeds. 

Then problem bothering me is, I had this a long time ago on my Ender and solved it, but forgot how. I always had some slow build up and every now and than a small blob with a string fell of, slightly burned after being attached to the hotend for a while.

Thanks for the advice 👍🏻

Posted : 09/05/2023 8:36 pm
jsw
 jsw
(@jsw)
Famed Member
RE: PETG Filament build up around the Nozzle

I can confirm that at least some of the Prusa branded filaments (non-Prusament) are the same as FilamentPM.  In particular, that silver-gray that used to be sent with each new printer is of FilamentPM origin.

My experience with PETg is that it is most definitely more oozy than PLA or ABS.  I've also observed that PETg does not produce as fine details as those two.

I've found that increasing the infill percentage on larger flat PETg pieces can indeed cause blobbing and accumulation on the nozzle.

Posted : 10/05/2023 10:26 pm
McBeary liked
McBeary
(@mcbeary)
Active Member
Topic starter answered:
RE: PETG Filament build up around the Nozzle

Interesting, I didn’t know, that ABS is better in details and less oozy as PETG. Unfortunately I don’t have the printer housed or in a place, where I can safely print ABS. But I’ll give it a try, once that changes.

And I got a Lotte update, maybe not scientific yet. I printed with the newest Alpha version of Prusa Slicer and the last stable one was less stringy. Before that, I increased the retraction to 1.2mm. The temp tower I printed looked good at 235, the print after had more strings as usual and a few burned blobs.With the stable version and more different objects, so a lot of travel between, almost no strings and just one small burned blob. So, it maybe this could be an issue too.

Posted : 11/05/2023 5:23 am
jsw
 jsw
(@jsw)
Famed Member
RE: PETG Filament build up around the Nozzle

I say that because when I started printing small gears for some mechanical projects, mostly model railroad related, I tried the gears in various filaments to see which ones worked better.

PLA worked the best for smaller-tooth gears, with ABS almost as good.

PETg not only gave poorer resolution on the smaller gear teeth, but it was noticeably softer than the other two.

I suspect that PC Blend might be even better, but the PLA gears do what I want.

I've found that ABS, for some reason, does a very nice job for some detailed pieces, such as fire escape stairs and railings for model railroad buildings.

If you want to print ABS without an enclosure, you can use the draft shield option to make a mini-enclosure around your print.  I did that before I got the enclosure and it does work well, particularly with smaller prints.

Posted : 11/05/2023 1:55 pm
McBeary and liked
McBeary
(@mcbeary)
Active Member
Topic starter answered:
RE: PETG Filament build up around the Nozzle

The problem I have with ABS is only the „toxic“ fumes. We don’t have much space, so I don’t have an extra room to print in at the moment.

But nevertheless, interesting what your experience is with it.

Posted : 11/05/2023 2:40 pm
Sunde Solutions
(@sunde-solutions)
Member
RE: PETG Filament build up around the Nozzle

I too had problems with this. Reading about several sources suggest a higher Z for the first layer. One source Sait 0.1mm about the thickness of two pieces of printing paper. So here is a caveman solution:

What if you place two pieces of paper under the nozzle during bed leveling before the print starts? I'm gonna try this with my next long-ish print.

Posted : 12/09/2023 5:07 am
yodakubota
(@yodakubota)
Active Member
RE: PETG Filament build up around the Nozzle

I'm getting a lot of build up around the nozzle too during printing with PETG on the XL. When I'm printing one color, it seems to build upon the first few layers. It comes off in the print usually, and the nozzle then doesn't have a huge mound of it on it any more. Seems to then print without building up quite so much. But I'm definitely seeing it come off in the print, which is disappointing.

I did the brass brush mod for the tool changers as well as the nozzle cleaning on the brass brushes before the print starts the first layer calibration (models found on Printables). This helps clean up any ooze before calibration but doesn't help during the print.

I run the filament from a filament drier during printing, and I run it a little bit each day on a scheduled timer to keep it dry inside. So it should be plenty dry. I found drying the filament really improved stringing on my MK3S so I run the drier when printing now.

I'm using the same filament (Overture PETG) that I've used for a few years with my MK3S. Printing PETG on the MK3S would require only removing a tiny bit of material from the end of the print nozzle after the print finished and cooled down. I never had buildup around the nozzle where I had to clean it with a brass brush.

With the XL, like others have said, I have to clean it before each print during the nozzle/bed warmup stage. But it builds back up again quickly.

With my MK3S, I'd clean the nozzle off cold, click Print, and walk away and come back when it was finished. Didn't have to think about it at all and it printed flawlessly. The XL I have to clean and monitor more, especially during the first few layers with large prints with lots of movements (large gridfinity bases) to make sure nothing gets messy.

If anyone finds a way to prevent this PETG buildup, I'd be very interested as I print almost entirely in PETG for functional parts.

Posted : 06/12/2023 1:54 am
Eric liked
JK
 JK
(@jk-2)
Member
RE: PETG Filament build up around the Nozzle

 

Posted by: @yodakubota

I'm getting a lot of build up around the nozzle too during printing with PETG on the XL. When I'm printing one color, it seems to build upon the first few layers. It comes off in the print usually, and the nozzle then doesn't have a huge mound of it on it any more. Seems to then print without building up quite so much. But I'm definitely seeing it come off in the print, which is disappointing.

I did the brass brush mod for the tool changers as well as the nozzle cleaning on the brass brushes before the print starts the first layer calibration (models found on Printables). This helps clean up any ooze before calibration but doesn't help during the print.

I run the filament from a filament drier during printing, and I run it a little bit each day on a scheduled timer to keep it dry inside. So it should be plenty dry. I found drying the filament really improved stringing on my MK3S so I run the drier when printing now.

I'm using the same filament (Overture PETG) that I've used for a few years with my MK3S. Printing PETG on the MK3S would require only removing a tiny bit of material from the end of the print nozzle after the print finished and cooled down. I never had buildup around the nozzle where I had to clean it with a brass brush.

With the XL, like others have said, I have to clean it before each print during the nozzle/bed warmup stage. But it builds back up again quickly.

With my MK3S, I'd clean the nozzle off cold, click Print, and walk away and come back when it was finished. Didn't have to think about it at all and it printed flawlessly. The XL I have to clean and monitor more, especially during the first few layers with large prints with lots of movements (large gridfinity bases) to make sure nothing gets messy.

If anyone finds a way to prevent this PETG buildup, I'd be very interested as I print almost entirely in PETG for functional parts.

Just curious if you ever found a solution here. I feel like I could have written your post verbatim (MK3S+ that printed PETG virtually perfectly, primarily using Overture PETG, printing directly from a drier, and excessive build up around the nozzle(s) on my XL with PETG). 

Posted : 02/10/2024 10:49 pm
Eric liked
Brian
(@brian-12)
Reputable Member
RE: PETG Filament build up around the Nozzle

I think the default nozzle offset that the firmware makes is too close for PETG.  Like others have mentioned it's much more suspectable to dragging and nozzle buildup on the first layer.

I print mostly PETG and I've found that during the first layer adjust the live Z by holding the knob down and then raising the nozzle ~ .02 (you'll have to watch and see what works best for your) helps significantly. 

The color of the filament surprisingly plays a role here as well with white for whatever reason being the worst.

Another thing you can do to help of to avoid the back and forth of the nozzle.  As it drags back by the line it just printed is when it tends to pick up material.  This can be avoided by changing the top and bottom surface profile to concentric.  Whether or not you want to do this is subjective.  Sometimes concentric looks better, especially on round parts, but can look off on others.  It's just another tool you can use.  You can use modifiers to only apply it to the first layer if you want. 

Another tip is to preheat for like 30 minutes.  This will help stabilize the bed shape since it will change as things heat up.  This can be helpful if printing multiple parts to keep the 1st layer consistent. 

I know it's said all the time, but especially with PETG it needs to be dried and kept dry.  In my experience this really affects stringing. 

If printing multiple colors/filaments use a wipe tower.  It helps get any blobs off the nozzle.

And finally there's no way around it, with PETG you need to clean your nozzle every print.  I usually just heat to 175 and if the buildup is not bad a quick wipe with a microfiber cloth does the trick.  If the buildup is heavy heat to 230 and use a brass brush.

Posted : 03/10/2024 4:22 am
ssmith liked
John
 John
(@john-6)
Reputable Member
RE: PETG Filament build up around the Nozzle

On my mk3s+ a silicon sock worked wonders for this issue. (Polymaker PETG)

i3 Mk3 [aug 2018] upgrade>>> i3MK3/S+[Dec 2023]

Posted : 05/10/2024 12:57 am
Eric
 Eric
(@eric-28)
Member
RE: PETG Filament build up around the Nozzle

 

Posted by: @jk-2

Just curious if you ever found a solution here. I feel like I could have written your post verbatim (MK3S+ that printed PETG virtually perfectly, primarily using Overture PETG, printing directly from a drier, and excessive build up around the nozzle(s) on my XL with PETG). 

And I feel like I could have written your post!  I see the very discussion I'm having issues with, and it's lots of discussion, but no actionable resolution..  Oh, get a sock and dry your stock.  My MK3 would print PETG all day without issue, sort of regretting the upgrade, now..

Posted : 22/10/2024 8:14 am
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