Layers Offsetting on Z18

[Superdave]

I'm having an issue with my Z18 not keeping layers stacked cleanly on top of each other. I printed a single shell circular test item last night and only parts of it are nice and smooth. The rest has a saw tooth appearance and feel. I noticed while it was printing that the extruder would change from clockwise to counter clockwise printing and that is when the layers would offset. Any ideas on how to correct this issue would be appreciated.

[LyalC52]

had the same problem awhile back
changed the so called "smart extruder" and the problem was gone
if you have a current makercare subscription, insist they send you a free replacment

[Superdave]

I find it hard to believe the extruder is the problem. It only puts material where it is positioned. I think there might be a issue with the drive system but I'm in touch with MB so we will see what happens. Thanks for the reply though.