After working on all the tips from last time the prints look much better now. Belts are tight, Extrusion is calibrated and retraction seems to be fine. Also switched to firmware retraction now. But there is onle last remaining thing. It seems that the holes in the front of the print effect the rest of the print, seen by the line that starts exactly where the hole starts. Also other features in the print seem to effect the outer shell negatively.
I have no idea how to get rid of that … Somebody some ideas?
Printed in PLA, 210°C at 40mm/s on a prusa i3 with full aluminum frame.
It looks like your belts might not be tight enough
Check your g-code, but I suspect that when the print reaches the front hole, the direction in which the perimeters rear of the hole are printed changes. This may indicate a loose belt in that direction [the direction of the indentation]. It may also be that the artifact is caused by changes in how the rear area cools while it is being printed (which happens when it takes more or less time for the infill and perimeters to get laid down). The latter would be a more subtle problem that likely needs an enclosure or low print speeds to correct.
[Edit: for clarity]
I’ve had this problem too and generally speaking it comes down to tuning. Once you get all parameters correct, the mechanics good etc these kinds of issues tend to disappear.
This print looks really bad (no offence:P) so I would work on general quality improvements and tuning before worrying about this particular problem.
I’m not sure what the quality problem here is though, looks like the extrusion is very uneven, maybe check that the extruder can extrude smoothly (no pull on the filament line, clean hobbed bolt/gear etc).
@Adam_Steinmark Tightened it again, even reprinted the tensioner now as it broke due to too much tension … well … suggesting a weak layer in the old part. But that should be good now.
@Michael_Hohensee whats the best way to see if it changes the direction in such cases? except printing it and waiting till it reaches that specific part.
@Oystein_Krog Yes, the prints do look really bad. No offence take 
Extruder is difficult, i have it extruding at around 99% the correct length of material. And holding the filament with my fingers is impossible, the geared extruder just pulls it. So I assume thats OK.
@Nathan_Walkner Thanks for your tips. Going to change the threaded rod to an 8mm one (currently 6mm). And yes, it seems to be a massive over extrusion. Printing a single layer wall results in a .8 mm thick wall, with a .4 mm nozzle. Which is kind of weird, as the extruder steps are calibrated correctly and I have no Idea currently what causes this. When using a multiplied of .5 now, the outer shell looks much better, but the infill and walls are separated from each other …
