PETG PRINTS BRITTLE, NO MATTER WHAT I DO?
Hi,
Im still pretty new to 3D printing and spent the last week putting about 60 straight hours of trouble shooting and have gotten NO WHERE. I feel like I read and tried everything possible on the internet, yet the problem persists. I am at the point where I believe the actual formula for the Prusament changed or a part on my machine is defective and I don't know what it is and that's why its not working.
About 7 months ago I made a 3D design and printed it with the Galaxy Black Prusament PETG, it was a basic cylinder. When I printed this and variations of this design 7 months ago, they all came out strong, hard and rigid, nearly indestructible. Like I would expect from PETG. I had saved the 3MF files and GCODE with all the settings, yet I didn't change much from the preset in Prusaslicer anyway. I did not use my printer in 7 months. It was turned off and sat inside the enclosure. I was using an enclosure then and now.
When I turned the printer back on, this last week, I tried printing the same GCODE with the same 3MF files and the prints are all coming out brittle, I did use a different new filament roll of PETG Galaxy black but it was vacuum sealed, but after 10 brittle prints, I thought some moisture must have gotten into it, so I dried it in my dehydrator at 60C for 6 hours, I even checked the dehydrator with a heat gun to be sure it was actually that temp. Printed again, exactly the same print, brittle. This was the beginning of 60 more hours of trouble shooting.
I thought maybe this roll was damaged (because the filament roll was the only thing that changed during that time, so I bought another roll, same brittle prints. I thought maybe that one somehow absorbed moisture too, so I then tried dehydrating that one too, no, still same brittleness. Its like its not even the same material I printed with. I then recalibrated my Z height, squared my machine, checked for clogs in the extruder, heatsink, heatbreak, checked to make sure nozzle is sealed against heatbreak inside the heatblock, checked and cleaned my bed with soap and water, isopropyl.
I then started printing variations of the same file with different cooling fan speed, temperature, but its always brittle now. I even printed at 260C with no fan, and the print still was brittle and easily cracked. Its like the material itself is not even PETG. Its like its not hardening into the strong plastic it should be, that it use to be. I can print and they can look identical to the ones I printed earlier but will easily crack.
Now I am at a complete lost, I am thinking the machine is broken, the software changed, or the prusament formula changed during that time. Every variation I try is coming no where close to the perfect prints I did just a few months earlier with all the same equipment, location, I even bought dehumidifier.
If anyone has a clue where I should go next please let me know. Or if the prusament did change please let me know and I will stop trying.
RE: PETG PRINTS BRITTLE, NO MATTER WHAT I DO?
In my experience, brittle PETG is either wet or poor quality.
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Chuck H
3D Printer Review Blog
RE: PETG PRINTS BRITTLE, NO MATTER WHAT I DO?
Can you expand on what you are calling brittle? Is it cracking across the layers? Do the layers come apart? Unless the PETG has somehow changed chemical composition I don't know how it could change characteristics. Even things I printed two years ago are about the same as when printed.
Regards,
Mark
RE: PETG PRINTS BRITTLE, NO MATTER WHAT I DO?
My experience is that PETg prints are never what I call brittle, as in will not easily break apart. I did have one ugly failed PETg print once, which broke apart when removing it from the build plate, but I had accidentally sliced it with PLA parameters instead of PETg. I'm lucky that it did not jam in the extruder.
PETg prints always seem a lot more supple than PLA/ABS prints, with a fair amount of 'give' to them, and tend to deform before breaking.
RE:
Hi, thanks for your replies. I made a quick video showing the issue, hopefully I clearly showed the problem in the video, apologies, I am on very little sleep trying to solve this.
I can also adjust my settings to a lower temp and then it wont be as brittle, but it will then be very squishy (pliable), like if I squeeze it, its like it just came off the bed. It will just squish down and deform, even hours after cooling off the bed. It doesn't hold the strong rigid tubular shape, so it always comes out either brittle or soft. It seems like moisture but how can it be after dehydrating and trying with different spools?
Anyway, thanks for any help or suggestions you guys can give, I need to make 100 of these by a deadline so I am really desperately trying to fix this issue.
Gratefully,
Arrow
RE: PETG PRINTS BRITTLE, NO MATTER WHAT I DO?
Oh shoot it doesn't look like I can send PMs or post links to YouTube so my link to my video didn't work, but by brittle I mean its breaking like a cheap plastic toy. It feels like its crystalized or something and with a bit of stress it cracks like a sheet of toffee candy or like a cheap McDonalds toy. I can print at low temperatures with no fan and get it to blend but then it feels like its just mushy and squishy no rigidity or strength. So either too brittle or too soft. Seems like a moisture issue but I don't understand how that's possible after drying it.
RE: PETG PRINTS BRITTLE, NO MATTER WHAT I DO?
It can always be wet filament. It is surprising how little time it take to hydrate some filaments.
Did you post the video?
Hi, thanks for your replies. I made a quick video showing the issue, hopefully I clearly showed the problem in the video, apologies, I am on very little sleep trying to solve this.
I can also adjust my settings to a lower temp and then it wont be as brittle, but it will then be very squishy (pliable), like if I squeeze it, its like it just came off the bed. It will just squish down and deform, even hours after cooling off the bed. It doesn't hold the strong rigid tubular shape, so it always comes out either brittle or soft. It seems like moisture but how can it be after dehydrating and trying with different spools?
Anyway, thanks for any help or suggestions you guys can give, I need to make 100 of these by a deadline so I am really desperately trying to fix this issue.
Gratefully,
Arrow
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Chuck H
3D Printer Review Blog
RE: PETG PRINTS BRITTLE, NO MATTER WHAT I DO?
Hi, that's what I keep thinking so I keep putting it in a dehydrator but maybe never long enough?
And I believe I clicked the add media and it embedded into the post, but it didn't seem to go thru, here it is again:
Maybe it was just in the wrong format, thanks for checking and your help.
RE: PETG PRINTS BRITTLE, NO MATTER WHAT I DO?
AD's video had some rogue formatting information stopping it from displaying.
I have removed the commands and the video is visible on my PC Now.
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
RE: PETG PRINTS BRITTLE, NO MATTER WHAT I DO?
I cannot offer any help, but I have just about 1:1 the same story. Mk3s, Prusament PETG, things printed months ago are sturdy af and new prints, even with spools fresh from the original vacuum bag, are brittle as hell and also the overall print quality is a lot worse.
Bought a dehidrator, dehidrated it for many hours, no big change.
RE:
Sounds like the formulation for the filament changed. Can anyone confirm this? Could it also be from not using the most current configuration and filament profiles from Prusa?
RE: PETG PRINTS BRITTLE, NO MATTER WHAT I DO?
Sorry, I too am no help. I am having the same issue. I am wondering if it was a firmware or slicer update.
I am using a Prusa MK3 S+ (or whatever) with an MMU2. Prusament PETG (black). Ironically - I don't think I am having this issue with my old MK2s. I will print something today on the MK2s and see if it's the filament.
RE: PETG PRINTS BRITTLE, NO MATTER WHAT I DO?
What temperature are you printing this with?
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Chuck H
3D Printer Review Blog
RE: PETG PRINTS BRITTLE, NO MATTER WHAT I DO?
I've found that, if anything, PETg is usually more supple and therefore less brittle than PLA, ABS, etc.
I have seen PETg filament get brittle when exposed to room air.
Is the filament you are using brittle? PETg will usually bend quite a bit without snapping. If it snaps, it's most likely damp.
The first thing I would try is drying the filament. For most filaments I run them overnight at 120F/49C in the Ninja Cooker set on dehydrate. I have only seen one case where doing this would not restore the printing quality of the filament in question.
RE: PETG PRINTS BRITTLE, NO MATTER WHAT I DO?
I have had similar findings but have also seen prints with less strength if they are printed at too fast a speed or at too low of a temp.
I've found that, if anything, PETg is usually more supple and therefore less brittle than PLA, ABS, etc.
I have seen PETg filament get brittle when exposed to room air.
Is the filament you are using brittle? PETg will usually bend quite a bit without snapping. If it snaps, it's most likely damp.
The first thing I would try is drying the filament. For most filaments I run them overnight at 120F/49C in the Ninja Cooker set on dehydrate. I have only seen one case where doing this would not restore the printing quality of the filament in question.
--------------------
Chuck H
3D Printer Review Blog
RE:
I have a totally different take from the above.. I've printed a ton of PETG and PLA.. You are printing that standing up on your build plate, and so the layer lines provide very little strength from sheer forces that try to break it.. You are not seeing brittleness in the filament, but a lack of layer adhesion from one layer to another.. from your video. you applied much force and you broke it across the layer lines. If you put one flat edge ( lengthways) on that tube and print lengthwises on your bed.. you won't be able to break it.
The question is why your first piece was so strong.. And that is because for some reason the layer adhesion was greater.. Lowering your temp is going to acerbate your perception of 'brittleness' because you'll get less layer adhesion. I am guessing that for the batch of filament you originally had, its layer adhesion was slightly better than later batches.. If you increase your temp 10C from your original 3MF settings you'll likely see a stronger part..
But if you want a lot of strength in the manner you are attempting to break it, you need to print the part flat on the bed .. often if these are axles, you can still flatten the top/bottom and it will rotate fine.. All my axles are square or 5 sided, when I want strength. The orientation you print parts will make a huge difference in part strength. In fact, orientation of how your print stuff has more to do with the strength of the part than almost any other factor.
I doubt any of your filament is 'bad'
RE: PETG PRINTS BRITTLE, NO MATTER WHAT I DO?
I had this same issues I contact prusa for hours and no results so I tried printing at 10 degrees c higher and that fixed it I was using petg black maybe the formula has changed
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RE: PETG PRINTS BRITTLE, NO MATTER WHAT I DO?
Update 2 for me. I went and bought brand new PETG (MicroCenter Inland PETG Gray) . It prints better than the Prusament PETG. Still brittle though. I have tried Temperatures, and different filament Profiles.
My bed adhesion is perfect, perfect first layers, all layers appear super nice - But the strength between the layers is as if they just aren't sticking together.
I do wonder if Prusa updated the firmware or slicer causing speed increase and or cooling fan increase that is causing this (Im not throwing blame - Im asking anyone from Prusa if this is true?). I have printed this PETG and the Prusament without issues in the past. I will print a few more today and try slowing the speed down, then I will try slowing the cooling fan.
You can just pull this apart easily.
RE: PETG PRINTS BRITTLE, NO MATTER WHAT I DO?
Any chance you have a hardware issue where your hotend is not getting to proper temp?
RE: PETG PRINTS BRITTLE, NO MATTER WHAT I DO?
Checked the hotend. Its spot on. Even changed the nozzle - just in case.