What is this and how do I fix it? Prusa Core One very bad print  

RE: What is this and how do I fix it? Prusa Core One very bad print

Pic of failed print

RE: What is this and how do I fix it? Prusa Core One very bad print

Hi,

Your picture didn't make it through but I will hazard a guess anyway.  The most likely cause of the spaghetti monster is poor bed adhesion which, in turn, leads to one of two issues.  The first is that the part breaks free from the bed and gets shoved out of position leading to nowhere for the filament to deposit.  The other possibility is that the print warped free of the plate which caused the printer to hit with enough force to cause it to lose position leading to printing where it isn't supposed to be.  The solution to both scenarios is to thoroughly clean the build sheet with HOT water and Dawn (Fairy in the UK) dish soap.  If you have a plastic scrubber sponge the scrubber side can be used to help ensure that small bits of plastic are removed.

If you need additional help perhaps try posting your picture again.

Regards,

Steve

RE: What is this and how do I fix it? Prusa Core One very bad print

Thank you for your reply.   I did clean the sheet before the print using Dawn soap and hot tap water (I have rinsed with distilled in the past, but not this particular time.)  I posted a second message because of the failed image load, I will try to repost in this reply too.  I believe the first layer did adhere, but at some point the entire print shifted in X and Y.  There was filament everywhere, I used a Shopvac to clean out the chamber.

Is there a print setting that is maybe slower but more "reliable"?

RE:

Ouch, that is quite a mess! Looking at the picture it seems that bed adhesion is not the culprit here, I don't see any evidence that any of the parts moved.  I assume as part of the clean up you would have mentioned that so we are left with the likelihood of a print head collision. 

You can certainly slow down the printing by selecting a different default profile (for instance the "structural" profiles run around 30-50% of the "speed" profiles depending upon the model.

Re-reading your original post I am interpreting that as you successfully printed one instance of this model (after some tweaking) and this failure was the result of attempting to print multiples of the successful print.  Provided that I am correct one other thing to try is carefully watching (actually listening) as the printer runs a single instance the print.  Certain infill types at higher densities can cause printhead collision issues as the crossovers of the infill are higher than the surrounding layer.  Too high density, coupled with high speed, can cause the printer to "lose steps" and thus position.   Your particular case looks to be more egregious than that however with a significant XY shift at around the 3mm height mark so I would pay close attention to interference in the print at that point listening carefully for "dragging" or "clunking" noises as the printhead moves across the print. 

You may need to select a less dense infill percentage (I rarely exceed 10-15% for most prints) or even a non-crossing (if density is important) infill such as "gyroid".  Even PLA is quite strong and doesn't usually require much infill, with increased perimeter count usually being more useful.  If you select infill density with an eye toward supporting the top layers for minimizing bridging length you will find you need far less.  You can also use modifiers in slicer to increase infill locally if necessary which will reduce material use and print time as well as helping to avoid the pitfalls of high density infills.

I hope that some of this is helpful in your investigation of what caused the failure.  

Regards,

Steve

P.S.  I just looked a little closer at your picture and see that you apparently sliced for a 0.1mm layer height which is almost certainly not necessary for a print that doesn't appear to have much fine detail.  The lower layer heights can increase the likelihood of collisions because the printhead is moving in such close proximity to the previous layer.  For a model as this one appears to be (mostly straight sides and "square" corners) I would take a look at using even the 0.25mm profile but certainly you shouldn't need below 0.2mm layer height.

RE: What is this and how do I fix it? Prusa Core One very bad print

It looks like you have layer shifts, the print has shifted the same on all items at a certain layer, and it seems to have happened more than once. Most of the other mess is likely from the printer trying to lay down filament in empty space after the layer shifts. I had this early with my pre assembled printer. I discovered that I had to retune belts, they loosened after some run in and needed tightening. But in my case the real reason was likely a setting for “don’t cross perimeters” that setting had at least at that point in time a track record of layer shifts when enabled, did you maybe use this setting? But since you printed one item successfully probably not.

I did not know about this setting problems when I ran into this but still managed to print by tuning belts, switching to the structured profile and gyroid infill which in my case removed long stretches of infill and this way reduced infill speed.

Another thought since you managed to print one item is high travel speed between items in combination with a loose belt.

RE: What is this and how do I fix it? Prusa Core One very bad print

I'm presuming that this is the same problem that I've just had?

That is if my image uploads properly?

RE: What is this and how do I fix it? Prusa Core One very bad print

Posted by: @franko

I'm presuming that this is the same problem that I've just had?

That is if my image uploads properly?

 83bb4f34-20250801_140807.jpg

It at least looks like two layer shifts, first a smaller one left and another up right, the pattern is too regular for this not to be a layer shift.

RE: What is this and how do I fix it? Prusa Core One very bad print

Posted by: @andhson

 

Posted by: @franko

I'm presuming that this is the same problem that I've just had?

That is if my image uploads properly?

 83bb4f34-20250801_140807.jpg

It at least looks like two layer shifts, first a smaller one left and another up right, the pattern is too regular for this not to be a layer shift.

Thank you for your input, I must admit that I farted about with the settings to try and speed up the print time 🫢.

Have set things back to default and all seems to be working fine ☺️ 

RE: What is this and how do I fix it? Prusa Core One very bad print

Had something very similar happen to me. At first i thought the belts of the motor pully's had come loose. Turns out the profile for, in this case, Esun PLA+ white, was at fault. In PrusaSlicer the main differences, compared to OrcaSlicer, were the flow rate (PS: 1; OS 0.98) and the max flow rate PS: 24mm3/s?; OS: 12mm3/s). When printing with the PS profile I had terrible ridges which caused the nozzle to collide.

In the video you can hear the nozzle scratch over the previous layer.

RE: What is this and how do I fix it? Prusa Core One very bad print

There is another thread and bug report regarding an issue with circular or arcing perimeters and "Do not cross perimeters" being set. Paraphrasing, it seems the slicer tells the printer to make and abrupt direction change that stalls a stepper.

RE: What is this and how do I fix it? Prusa Core One very bad print

I had a similar problem, my hot-end was loose and moving during printing, I tightened the two large screws by hand and everything was fine.