Slight layer shifting and bumps near the corners when printing a cube
Hello!
I tried printing a cube (the visual method cube to see if my extrusion multiplier was okish), but I'm noticing that the side walls aren't that smooth and I'm also noticing some small bumps where the nozzle starts/stops placing filament on the outer walls. Is there any way to fix/alleviate these issues or is this a common issue that I can just sand away? So far I'm having a great time with my Prusa
RE: Slight layer shifting and bumps near the corners when printing a cube
Lots of parameters to play with, but the wall variation, or smoothness, can be related to belt tension. Loose belts reduce positional accuracy and allow motions to vibrate through to the other axis. Keep in mind the LCD belt tension numbers are not helpful; at all, they only show motor currents needed to overcome friction. You'll need a method of measuring actual belt tension to get close to ideal - 6 to 8 pounds force.
Extrusion start-stops are a combination of jerk, acceleration, nozzle pressure, and luck. There's an adjustment that can help; the default is pretty close, but you can print tests to see if a minor change will help. Search for Linear Advance, and you can start here: http://marlinfw.org/docs/features/lin_advance.html
There are also settings for filament retraction and un-retraction that affects seams. It all plays off of extrusion multiplier and actual filament diameters (and types). Also, some filaments just behave better. No simple single "do this and all will be well" answer.