Warpage or lift off of print, "print failure"

[WobblyHand]

In the last four prints, I have had the piece lift off the plate twice. Both near the end of the prints. The prints are tall relative to their area on the plate. 40mm OD, 165mm high for this last one. I'm trying to reduce this print failure rate to a very low level. The part is in PETG. I'm using a Prusa i3 Mark3S+ printer with PrusaSlicer 2.6.1. Print file is pretty large 37MB. I did make a project file, it is 10MB. I can attach them if it is ok.

Things I have tried:
1. Used satin steel sheet, which I originally had over adhesion issues.
2. Cleaned sheet with 99% isopropyl alcohol prior to use
3. Sprayed AquaNet hair spray on a cold sheet and wipe off most of the liquid with Kim Wipes
4. Added a wide brim to the part
5. Print in draft mode, with variable layer height for the upper section. This is primarily to reduce print time in the object, and get narrower layers for the top of the part
6. Fan speed min 30% - 50%. Disable fan for first 3 layers. "Full fan" at layer 5.

After this print I will look into reexamining the bed leveling. It's been a while. I haven't moved the printer at all since the last time, not sure why things would change, but, stuff happens.

Anything else that I should change or do? Losing an 8 hour print after 7.5 hours is no fun, hobby or not. For one thing, it makes you second guess your design, and then you fiddle around making improvements. These are exploratory prints to try to see what works better.

 

[vtcnc]

Rafts have been my bulletproof go to countermeasure for lift. It adds considerable time to the print but if it is a long print, I haven’t regretted the extra time.


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[WobblyHand]

Rafts have been my bulletproof go to countermeasure for lift. It adds considerable time to the print but if it is a long print, I haven’t regretted the extra time.


Sent from my iPhone using Tapatalk

Can you explain a raft? What exactly is a raft? How does it differ from a brim? I was quite confused when reading this.

This print might go ok. Previous prints had 2 perimeters, and the printer was shaking filling in the in between area. I changed it to 3 perimeters and now the cylinder walls are being printed as simple big circles, with no jerky movements, like a sane person would expect. I've seen some really surprising fill patterns in this version of the slicer, a lot weirder than in the past. The fill areas were not at all what I had expected. Of course, thinking that things are ok might all be wishful thinking as I am only at 75mm, less than half way.

 

[Ken226]

40mm diameter on the bed x 165mm high is very unlikely to be a warping issue, and much more likely to be a bed adhesion issue. It's not a lot of area, but should be plenty enough for a print.

PETG is known for sticking to the bed very well. So much so, that a light misting of hair spray as a release agent can save you from build plate destruction.


If your PETG prints are releasing prematurely during a print, you likely have your nozzles Z height set too high.

What kind of printer are you using, and how did you calibrate your nozzles height above the build plate? Can you double check your Z height calibration?

For reference, with my Voron 2.4 and my Flashforge Creator Pro, I use a torn off strip of printer paper (.1mm thick) as a feeler gauge. I set the nozzle over the center of the bed and lower it until I feel a light drag on the paper.

I then remove the paper and lower the nozzle .05mm more and reset that point as Zero.

Edit to add:
A raft is basically a sacrificial layer. You printer lays down some thick extrusion lines in a grid, or some other pattern, to create a plastic bed, then prints on top of that raft. It is really useful when you have adhesion problems due to a bad nozzle height calibrations. Amongst other things.

 

[WobblyHand]

40mm diameter on the bed x 165mm high is very unlikely to be a warping issue, and much more likely to be a bed adhesion issue. It's not a lot of area, but should be plenty enough for a print.

PETG is known for sticking to the bed very well. So much so, that a light misting of hair spray as a release agent can save you from build plate destruction.


If your PETG prints are releasing prematurely during a print, you likely have your nozzles Z height set too high.

What kind of printer are you using, and how did you calibrate your nozzles height above the build plate? Can you double check your Z height calibration?

For reference, with my Voron 2.4 and my Flashforge Creator Pro, I use a torn off strip of printer paper (.1mm thick) as a feeler gauge. I set the nozzle over the center of the bed and lower it until I feel a light drag on the paper.

I then remove the paper and lower the nozzle .05mm more and reset that point as Zero.

Edit to add:
A raft is basically a sacrificial layer. You printer lays down some thick extrusion lines in a grid, or some other pattern, to create a plastic bed, then prints on top of that raft. It is really useful when you have adhesion problems due to a bad nozzle height calibrations. Amongst other things.

Prusa i3 Mk3S+ (first post!) Standard cal procedure, for setting z height. Still have some of the square pads left with their setting value written on them. Maybe something changed in z height, worth checking again. That will be next.

Thanks for the answer on the raft. So a brim is 1 layer and a raft can be higher or thicker?

Watching the gcode/print head movement makes me wonder what kind of dope someone was smoking when they wrote the code for the slicer. It's not an easy task to optimize a slicer, but the movement at times doesn't make a whole lot of sense. Sometimes it seems reasonable and others it's pretty wacky. Hard to explain. Just seems like there's more jerkiness than needed. Which is something you notice when your prints are falling over.

 

[DavidR8]

I was having adhesion issues with my ender till I added a small negative Z offset. Oh rafts helped too. So maybe both were the magic combo?

 

[MikeWi]

Look up the Brim setting in your slicer. it provides a much larger footprint for the print, and can help prevent this. I just use one layer thick and maybe 6mm wide. This also could be from a lot of other things, like cooling too fast, or the bed isn't prepped well enough for two easy examples.

 

[Lo-Fi]

3DLac spray has been really good for me on my Ender 5 with textured glass bed. I always use a skirt at minimum or a brim if the parts are likely to try peeling. Rafts are too much hassle to remove for me, and lots of my prints leverage the fact that the surface that was on the bed ends up nice and flat for glueing together. It's got so reliable, I tend to send the print job and don't even bother to check in if the first layer is going down ok.

Give a nice wide (1/2") brim a go, see how you get on.

 

[WobblyHand]

I actually observed the problem just before it occurred and just after. The problem is there are "boogers" or small bits that somehow are being left behind. They are above the level of the print. When the extruder comes along on the next pass and whacks the hardened booger, the print gets knocked over, especially if the lever arm is long. I paused the print as it got knocked and the print was wedged into the extruder. Third failed print out of 5 tries. Died at 156mm, out of a 165mm print. Darn! I heard a couple of small whacks, say once every 3 or 4 minutes, and didn't know what it was. Well, if you hit the top of the print repeatedly, with the print head going sideways, eventually you will loose adhesion. The boogie man got me...

Is this a nozzle problem? Hot end?

I was printing with Prusament PETG, which I thought would be ok.

I was printing variable layers at that point in the print, trying to get nicer threads.

Seems there's over extrusion, or insufficient retraction and something gets deposited when it shouldn't. I'm in over my head on this one. What to do?

 

[Ken226]

I actually observed the problem just before it occurred and just after. The problem is there are "boogers" or small bits that somehow are being left behind. They are above the level of the print. When the extruder comes along on the next pass and whacks the hardened booger, the print gets knocked over, especially if the lever arm is long. I paused the print as it got knocked and the print was wedged into the extruder. Third failed print out of 5 tries. Died at 156mm, out of a 165mm print. Darn! I heard a couple of small whacks, say once every 3 or 4 minutes, and didn't know what it was. Well, if you hit the top of the print repeatedly, with the print head going sideways, eventually you will loose adhesion. The boogie man got me...

Is this a nozzle problem? Hot end?

I was printing with Prusament PETG, which I thought would be ok.

I was printing variable layers at that point in the print, trying to get nicer threads.

Seems there's over extrusion, or insufficient retraction and something gets deposited when it shouldn't. I'm in over my head on this one. What to do?

That description sounds like more of an overextrusion issue. Maybe try a test print with the extrusion multiplier set to 99%


Have a look at this thread.

PETG Boogers or Blobs or Artifacts

So I am not new to printing (printed ABS for years fairly well) but I am new to Prusa and PETG. I bought some of the Green transparent PETG filament f...

forum.prusa3d.com

Particularly this post by rob-l6. It seemed to help some folks having similar issues:

Posted by: Rob-l6
Try these settings, works for me and many others ...
Retract Length = 0.4
Lift Z = 0
Retract Speed = 35