Strangely shifted/extended printing
Hello,
My first post, so sorry if I posted something wrong.
Does somebody know why the parts on the picture are printed in so strange way and how to fix it? There is a shift in vertical pillars between empty levels and levels with the bridge printed. It happens on both side of the printed body and in opposite directions, so it is not just a shift. It makes the body wider there. The difference is nearly 1mm on each side. I've printed it several times, always the same result. I am using the very standard setting in prusa-slicer. Printer: Original Prusa i3 MK3, Filament: Plasty Mladec PLA, Print setting: 0.20mm SPEED. 
Thanks in advance,
Marian
Please save your project as a .3mf file
Files > Save Project as
Zip the .3mf and post it here. It will contain both your part and your settings for us to diagnose.
Cheerio,
RE:
Here it is. I've upgraded the design a little bit, but it is still doing the same thing. I did not find a way how to attach a binary file to the post, I am posting a link: http://www.xrefactory.com/prusa/d2-prop-guard.3mf . I have included .stl and .gcode. It is all in http://www.xrefactory.com/prusa .
RE: Strangely shifted/extended printing
My wild guess is that it's an instance of the "bulge", which happens at such transition points. See
among other threads on that topic in this forum.
With the thin walls of this object this may be tough to tackle, I'd try "external perimeters first", and maybe adjusting the extrusion width in those regions.
Formerly known on this forum as @fuchsr -- until all hell broke loose with the forum software...
RE: Strangely shifted/extended printing
Thank you very much. I have checked the link and made a few more attempts. I'm not sure if this can help other guys with the "bulging" problem, but in my case the problem was (probably) caused by the filament shrinking as it cooled. What actually happened in my case was that the first few layers of the bridge shrunk and bent the pillars into the body. When the bridge was thick enough, the shrinkage stopped and the shape resumed normally.
In my case, the bottom and top layers are actually the correct size. The uprights are not vertical, they were bent by the shrunken bridge.
Marian
Close, but not quite.
I printed a test and reproduced your case. The inward lean is caused by contraction, as it cools, of the upper part of the guard hoop.
To prevent (most) of it add a thin buttress on the inside of each of the end posts; you can snap it off later if it's in the way.
Cheerio,
RE: Strangely shifted/extended printing
Yes, thanks, I fixed it in this way. Standard generated support fixes it as well.