unfortunately things came out quite worse then expected on first sight. While the printer ran quite well at the beginning i noticed jumps on the Y axis after some layers of printing. After investigating a bit i noticed that the friction on Y was quite high, so I invested some time to find out why and re-check geometry and everything.
Turns out a small error somehwere on the hotend carriage seems to cause this problem. Most probably you wouldn’t have noticed this on your versions with the self aligning bushings but it turned out to be really nasty with the robotdigg graphite bushings. Problem is that they are 60mm long and even though they are covered with a thing sleeve printed of flex filament they don’t forgive too much of an angular error.
Currently the whole X/Y part is unmounted again and i’m thinking about possible next steps. I still don’t know if the error comes from a not-so-good print of the carriage (don’t think so as this print was really quite perfect) or probably some printing errorness on the flex sleeves. I thought about glueing in the bushings with a glue that dries to a foamy structure (like gorilla glue). This should make it a perfect fit when hardened “in position” - unfortunately i won’t get this stuff out again if it fails
I also thought about using ball bearings in the center - these are much more forgiving regarding errors and much more insensible. Another alternative of course would be to reprint the whole carriage and use self aligning bushings. Unfortunately they’re hard to source in Europe. Haven’t found any suppliers yet.
That’s it for now - just wanted to give you an update on my frustration level