Curious to what this is and why it happened with my print
I was printing another identical piece using the same saved gcode today and when I went to check on it it looked like the pics below. It was as if the layers shifted to the back of the build plate twice. Then I looked more closely and saw a burnt looking glob or two of what I assume is burnt PETG. What would cause this? A thermistor not controlling the temp? I re-sliced the part again and its running fine so far and all I did to change it was I flipped it sideways instead of printing is with the long side front to back.
Thanks
RE: Curious to what this is and why it happened with my print
Plenty of things that can cause layer shifts. On the printer side, it could be loose belts or grub screw on the motor shafts, or the hotend hitting an obstacle such as a zip tie end. On the print side, warping (especially overhangs) can cause the hotend to hit the print and cause a layer shift. Or the model got loose and moved around on the steel sheet. Also, you seemed to be using grid infill, which has interesting lines within a layer, which can lead to pileups of filament at the intersection points that the nozzle may hit.
On a Mk3 I might also check for filament dropping from the hotend because of a wrongly installed nozzle.
In this case, because it seems to be an isolated event, my guess is the infill.
RE: Curious to what this is and why it happened with my print
I am guessing it was a one time glitch as I have printed the same item over and only changed the layout from north/south to east/west and it printed perfect. I just used the default grid infill pattern in simple mode like I did on all my other successful prints. There was no warping on the first layers and the model didn't come loose. It's a brand new factory built MK4. Thanks for your insight and I will be sure to check those grub screws. I just thought it was weird having the burnt filament in there in blobs. Maybe the nozzle get partially plugged and then unplugged itself. I need to get Octoprint and a camera set up unless there is something better nowadays.
RE: Curious to what this is and why it happened with my print
Blobs could have been nozzle picking up filament at the grid intersections.
RE: Curious to what this is and why it happened with my print
So could the orientation of a part make that happen where one way it works ok, and the other way is prone to issues?? I normally lay things out east/west with rectangles but on the failed part I left it in the north/south position as that is how the original opened up.
Thanks
RE: Curious to what this is and why it happened with my print
Orientation could indeed make a difference but I don't think I can offer a simple rule that minimizes the risk of collisions.
RE: Curious to what this is and why it happened with my print
I think it was a glitch that should have been caught on a camera to really understand what happened. I have done 3 prints after the incident and all have turned out great. Thanks for your insight into my issue.