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PETG PRINTS BRITTLE, NO MATTER WHAT I DO?  

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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.

 

 

 

 

 

 

Posted : 22/06/2022 11:54 am
cwbullet
(@cwbullet)
RE: PETG PRINTS BRITTLE, NO MATTER WHAT I DO?

In my experience, brittle PETG is either wet or poor quality.  

--------------------
Chuck H
3D Printer Review Blog

Posted : 22/06/2022 4:07 pm
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mark
 mark
(@mark-3)
Reputable Member
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

Posted : 22/06/2022 7:37 pm
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jsw
 jsw
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Noble Member
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.

Posted : 22/06/2022 8:41 pm
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Topic starter answered:
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

Posted : 22/06/2022 10:12 pm
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Topic starter answered:
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.

Posted : 23/06/2022 10:20 am
cwbullet
(@cwbullet)
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?   

Posted by: @ad-2

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

 

--------------------
Chuck H
3D Printer Review Blog

Posted : 23/06/2022 10:46 am
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Topic starter answered:
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.

 

 

Posted : 23/06/2022 2:07 pm
JoanTabb
(@joantabb)
Moderator
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

Posted : 23/06/2022 4:03 pm
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