I've been printing more at 0.1mm and there are bands that were scarcely perceptible at 0.25mm. Generally they amount to one layer that has shifted the tiniest amount to the right and front.... just enough to create a line. Usually after one layer it then returns to where it was before. I've tried: - tightening all the different aspects of the motion system; - checking the hotend and nozzle are secure; - examining the belts; - verifying the steppers are at the top end of their range; I don't think it's the Z-axis because the bands vary from part to part. And because I can't "force" bands to appear by pushing a bit on the side of the bed during printing. The bands are however more frequent when there is more "going on" on the layers. So it makes me think it's somehow related to the X-Y motion. However decreasing the speed - both of printing and of XY movements - makes no difference. All ears for suggestions!