I'm getting a glitch in some of my prints, where the layer shifts over by about an extrusion width when there is a change in cross-section. In my case extrusion width is 0.5mm (nozzle diameter). The change in cross section can be a lateral hole finishing, or a simple change in section. It doesn't always happen, but when it does, it looks bad (the rest of the walls built up look fine, so the glitch stands out - from this I infer that the X & Y movements don't have backlash or sloppiness) and it weakens the print, so that it tends to split apart at this glitch. The layers are still regular, so I don't think it's missing anything.
There's a couple of photos which should illustrate what I mean
I use Sketchup for designing, and Pronterface to drive a mk1 Prusa. I generally put the .stl files through Netfabb before printing. Printing in ABS.
I can't be sure, but it looks like the layers drift back into true after the glitch, though over at least several mm of layers.
I'd love to get rid of this artefact; does anyone know what might cause this, or how it may be fixed?
