Purge tower lines / paths in space at the top of a print issue
I keep getting this issue where phantom lines appear in space several inches above the top of a purge tower with this model. It is a simple cover with some letters printed in a different color on the print bed only for the first 3 layers. The print successfully completes, and then as a last action the head moves over the tower (that it hasn't used for ~hundreds of layers) and extrudes two paths into space. Luckily, it doesn't mess up the print at all, but I cant get the issue to go away no matter how I slice it. Have tried all kinds of positioning combinations and with/without supports as well as different extruder combinations and layer heights. Always shows up.. Cant think of any other options to try to make it go away. Anyone have a theory?
it's intentional - the extruder is purging as it unloads the filament at the end of the job. no need to build a purge tower up that high when all that's left is a move to the park position.
again it's intentional - either they build the tower up to the top level used ( wasting lots of filament) or they purge in mid air over the tower and have a loose purge to clean up. the purge is needed because they run a regular filament unload with purge at the end of the job so there is no filament in the extruder or selector in preparation for the next job