I have a new issue. I have successfully printed the same types of models that are tall and very long prints (over 24 hours) several times in the past. Recently I have tried to print a similar model three or four times now and it looks fantastic for almost 24 hours straight and then it will turn into a spaghetti mess and I have no idea why. I am using a microswiss hotend with the regular nozzle not the CHT one. I have PID tuned. But I did notice something that makes me wonder if it is the cause.
Because the prints keep failing when the gantry is at a very high z height, I noticed that when I home the printer after the failure from that Z height that the cable drags across the linear rail and bumps and brushes against the belts on that rail and the gantry rail next to it on the X axis. Could it be rubbing the belts and causing missed steps or something at this z height resulting in the spaghetti mess? All other shorter prints work fine.
It sounds like you don’t have the enclosure right ?
The cable chain that is also used for the enclosure might help in this case, I also tie-wrapped a stainless steel (springsteel) to the toolhead cable making it arch high instead of dragging it around.
I think that is mainly for the cable between the base and the flying gantry not to get pinched between the gantry and the enclosure or pinched between the gantry and the base.
Did you manage to solve the confusion when printing high? Two days ago I printed a box with a height of 305mm, after 20 hours I threw away a layer and a kilogram of plastic in the trash. Now it prints again, so after reading your post I'm worried.
@matopelikan57 so yes I was able to print the same troubled model after 3 failed attempts and 3 wasted kgs of filament. I made four changes, one was I removed the spool holder and changed to feeding from my filament dryer with a printed bracket from printables that put the filament run out sensor at a 45 degree angle, I switched the ptfe tube to a better one, I upgraded to the sovol Eddy sensor, I added a printed bracket to the back part of the gantry to support the cable on an upright position.
Which of these solved the issue I am not sure, but I feel like the position of the filament run out sensor and the cable bracket on the gantry were probably the changes directly related. I think the cable was hitting the belts at that height and causing a layer shift..
