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Help! PETG prints failing  

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The Bearded Nun
(@the-bearded-nun)
New Member
Help! PETG prints failing

So I started working with PETG after getting my MK3S alittle over 6 weeks ago and the first few prints done with my 0.4mm nozzle came out beautifully.

However, after switching to a 0.6mm nozzle I've had repeated failures on multiple models where the X-axis carriage will somehow Fuze itself to the print at roughly 3-4 hours in. 

I've cleaned the sheet, done 2 cold pulls, dried the filament, backed off Z adjust as far as I think I can, upped nozzle temp to 255, all to no effect. 

I've printed several items successfully with bed time of about 1-2 hours with zero problems. It's also worth noting the print even when it fails looks beautiful save it sticking the carriage.

Hardware is setup fine on the machine, I've triple checked the PRUSA Slicer profile for nozzle diameter.

Posted : 04/07/2022 7:45 pm
cwbullet
(@cwbullet)
Member
RE: Help! PETG prints failing

Have you recalibrated your first layer with the new nozzle?  

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

Posted : 04/07/2022 8:35 pm
The Bearded Nun
(@the-bearded-nun)
New Member
Topic starter answered:
RE: Help! PETG prints failing

 

Posted by: @cwbullet

Have you recalibrated your first layer with the new nozzle?  

Yes I did, I did experience an inability to perform first layer Z adjust from the test underextruding. But I've found afew threads stating the test doesn't adjust well to the .6mm.

I ran a calibration cube as an alternative that came out .001mm off on the Y axis.

Posted : 04/07/2022 9:16 pm
Crab
 Crab
(@crab)
Reputable Member
RE: Help! PETG prints failing

What sheet are you using?

I haven't tried a larger nozzle..  and weird that the Z calibration in the firmware would under extrude.. but you can find "life adjust my way" (typo in heading) and print a square and use the live adjust to get your Z good. I'm assuming you are using the rough sheet because PETG generally sticks too well to the smooth sheet.. in fact if you can damage the PEI coating if you don't use a release agent. 

You can also try raising the bed temp 5 deg. What filament are you using?

Posted : 04/07/2022 11:20 pm
The Bearded Nun
(@the-bearded-nun)
New Member
Topic starter answered:
RE: Help! PETG prints failing

 

Posted by: @crab

What sheet are you using?

I haven't tried a larger nozzle..  and weird that the Z calibration in the firmware would under extrude.. but you can find "life adjust my way" (typo in heading) and print a square and use the live adjust to get your Z good. I'm assuming you are using the rough sheet because PETG generally sticks too well to the smooth sheet.. in fact if you can damage the PEI coating if you don't use a release agent. 

You can also try raising the bed temp 5 deg. What filament are you using?

Yes, it's the textured PEI sheet. I suspected it may be raising by just enough to cause contact with the nozzle so I added Layerneer adhesive to the surface after I cleaned it.

And as for the filament, it's Prusament Galaxy Black.

Posted : 05/07/2022 12:31 am
Crab
 Crab
(@crab)
Reputable Member
RE:

I absolutely love my textured sheet for PETG and I've used 3 different brands included Prusa. It works flawlessly on nearly every print. It is more dependable than PLA on my smooth sheet. I had to really scrub that sucker quite a bit to get all the packing film off.. I just used the soft side of a dish sponge with lots of dish soap. You should not need any adhesive. If you do, I would increase the bed temp 5 degrees on the first layer (a slicer setting) to see if that helps.. But maybe your Z is not optimum.. That is my guess. I'd get some one layer squares and do a live Z adjustment..

Posted : 05/07/2022 1:03 am
jsw
 jsw
(@jsw)
Famed Member
RE: Help! PETG prints failing

I've done countless PETg (as well as PLA and ABS) prints on the textured plate and I really like the finish.  I'm still looking for an equivalent textured plate for my other printer (Ultimaker S5) but I have yet to find one that's a full-size and no-nonsense drop-in compatible.

One hint I will offer with the textured plate is on the Z calibration, which is more critical than on a smooth plate.

I get the best results, and the most visually appealing textured finish when I 'tune' the Z just to the point that the 'brush strokes' of the extruded beads just disappear into the textured surface, using either the built-in Z calibration or those 3x3 calibration prints.

I also use Layerneer on most textured plate prints, both as an adhesion booster and a release agent.

Posted : 05/07/2022 4:59 pm
RandyM9
(@randym9)
Honorable Member
RE: Help! PETG prints failing

I get the best results, and the most visually appealing textured finish when I 'tune' the Z just to the point that the 'brush strokes' of the extruded beads just disappear into the textured surface, using either the built-in Z calibration or those 3x3 calibration prints.

+1 … I tune the Z to the same type of textured bottom surface with no visible parallel lines. I use the ‘life adjust Z - my way’ routine for this typically.

Never needed a release agent with the textured sheet. Prints just pop off when they cool. Of course, your mileage may vary.

It’s not clear from the OP’s original post if the issue is the print separating from the bed and getting ‘fuzed’ to the hot end or some other issue. 

Give the sheet a good cleaning, get the Z dialed in tight, and try the release agent suggested above.

Good luck!

Posted : 05/07/2022 8:28 pm
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