I have this PETG; its Kingroon Blue PETG. I can’t get it to print nicely no matter what I do. Been testing with benchy over and over.
The filament is as dry as I can make it. It’s been in the dryer for at least 12 hours before each print. I even have tried snipping the part of the filament not in the dryer to start from a dried state. The Relative Humidity doesn’t drop anymore at this point (from 19ish).
I’ve tried different temperatures from 220 to 260. I’ve tried different retraction lengths and speeds. I’ve tried with the cooling fan on/off and at a couple middling percentages. Also different speeds from 30mm/s to 45 to 60.
I tried printing a retraction tower and it fell apart after the first level.
The first layer prints more/less fine, then eventually it either just falls apart (most of the time) or produces something in awful quality.
I’ve attached images of everything I can think of from the way it looks on the first layer, to the case where its a benchy out of a horror film, to when it just fails miserably.
Printer Elegoo Neptune 3 Plus. .4mm nozzle (i’ve tried both copper and hardened steel). Besides the nozzle its stock. If I swap to PLA it prints generally fine.
I feel like I’m missing something obvious. Everyone says dry the filament, but I can’t dry it anymore 😢 .
Thanks folks (and if you celebrate: Happy Turkey Day!)
To do process of elimination, I’d recommend trying a different brand of filament and a different type of filament (i.e. PLA), preferably freshly opened rolls. I’d also generally be wary of AliExpress, but that’s just been my experience of seeing multiple people be disappointed with what they get. If you’re looking for discounts on filament, there are a bunch of Black Friday deals going on right now.
That testing will at least tell you if it’s the brand or the type of filament that’s causing the issue. If you eliminate those by seeing no change, then you know it’s the printer itself and can start troubleshooting that next.
I’ve printed kilos and kilos of Geeetech PLA, and that’s some of the cheapest on AliExpress (although I used to get it directly from their website before I realised doing that was normally more expensive). It arrives wet, but other than that, there’s (nearly) nothing to complain about (although years ago, I had a roll with two lumps of grit in it that caused clogs). I’ve had mixed success with their other materials - their ABS+ started burning in the nozzle while still being cold enough that layer adhesion was bad and their high-speed PLA has ridiculous oozing that causes ridiculous stringing, but their PETG and TPU seem fine. I’m pretty confident that their basic materials are absolutely worth £7/kg.
As others have said, you are severely under-extruding.
Looking at your pictures, I do see a potentially major issue that nobody has addressed: the taughtness of the filament between your hot end and runout sensor. It does not look like filament is being fed to the extruder easily enough for the extruder gears to grip the filament. If you’re able to print other filaments, it’s possible that this one has a harder or slicker surface than say PLA.
I would try temporarily disabling the runout sensor, and routing the filament under the top bar, directly to the hotend, to test this.
I instead tried printing directly from the spool holder immediately after taking it out of the dryer. Same thing happened. I doubt it could have moisture-d up that fast for it to make a difference
For good measure I tried going direct from the dryer to the hot end (and just left a piece in the runout sensor to have it not trip). More/less the same problems: https://imgur.com/a/65jzAQv … I stopped it early since it was failing terribly. Otherwise was using default cura generic PETG settings on .3mm per layer with .4mm nozzle.
You’re severely under-extruding. This may sound weird, but try a warmer temp tower without any extrusion. You might be developing a clog mid print.
What’s the recommendation to fix under extrusion? I tried changing the flow in cura to 102 then later to 118… no obvious differences.
Upping the flow isn’t the problem then. In my experience, flow only ever varies between 95 and 105%. It’s there to compensate for thinner or thicker than expected filament. The under extrusion is caused by something else. Possibly a blockage, possibly to much drag. Pushing harder, aka more flow, might not help.
PETG isn’t very tolerant of too much retraction. Given your fine first layer I suspect you’re developing a clog as the print goes on, which would result in under extrusion. Turning retraction completely off will make it very easy to rule out as a possibility.
How can you tell it’s under extruded?
@PostnataleAbtreibung@lemmy.world said the same thing in an earlier comment.
If there’s some clear sign of under extrusion it might be useful for my reference doc I use when trying to troubleshoot failed prints.
How can you tell it’s under extruded?
IMO this is the same as any other hobby. Print enough and you’re likely to run into under extrusion at some point. Similarly, I can tell if doughs and batters needs more liquid or more flower by look and touch thanks to making a ton of pizza crusts and pancakes.
If there’s some clear sign of under extrusion it might be useful for my reference doc I use when trying to troubleshoot failed prints.
The first photo in the album looks like ‘classic’ under extrusion. The layer lines are largely intact, but way less material that is necessary for a solid print is present. The print has better and worse areas, which usually indicates a clog. Combine this with the fact that PETG will clog if you use too much retraction and a user that’s new to PETG and retraction seems like a good place to start troubleshooting.
As for helping your guide, simplify3d hasn’t been a ‘cool’ slicer in quite some time but they have a decent print quality guide that names a bunch of failure modes. Ellis’ print tuning guide is the best one I’ve come across.
Are you able to print in PETG at all, or is it just this one specifically that gives you issues?
Should I try a different one? I think all I have are Kingroon PETGs. I got them from a bundle of 10: https://www.aliexpress.us/item/3256806452989007.html … I have different colors though.
Never heard of Kingroon.
I’d try a known good company first.
I once had a nightmarish time with some cheap filament and thought my printer just can’t do PETG well. Then I got a good roll from a different company and it printed even cleaner than PLA…
Had a similar experience; I’d recommend trying something like Prusa filament to start with as I’ve found it to be consistently high quality. From there if it looks good try for something economical
Don‘t know the brand, but the filament without tubes looks strange to me. Might get a bit too much uv and humidity on the long way.
It looks like a massive underextrusion. So you might want to check the retraction speed (20mm/s to 30mm/s) and the tempereature as well as the flow rate and tinker a bit with it. But honestly, it looks like they are lacking the glycole way too hard
