Trouble printing small thin pole 3D-printing newbie here. I have a Geeetech's Prusa i3 mk2 B.

I'm trying to print this: https://www.thingiverse.com/thing:1358311

That's a mold, with 2 external parts and a core. The exterior prints wonderful. But the core is too messy. Take a look at this: 



What riddles me is that the side parts, and the pole's base, print fine; so this does not look like a bad calibrated printer, but something else entirely. My guess is this is some precise tuning I don't know yet. 

I've been trying to print that little pole without success for over a week now. Tried all this:


Changing the slicer program (I've used Ultimaker Cura and Slic3r prusa edition)
Tuning the e-steps for avoiding over-extrusion.
Tuning the z-steps, so the nozzle doesn't melt the last layer when printing a new one.
In the same sense, changed the nozzle heat.
Tried lots of different layering, speed, walls, bridging, and quirks configurations.


So far, the best I got is a little pole not-too-deformed so I can make my part anyway, even when the pole is not well printed. But after seeing lots of videos and reading lots of tips online, I still don't understand how to tune my print for that simple little pole.

Other that tips, what I would really like to ask is if somebody has a name for that problem I'm facing, so it would be much more easy to search for my tuning options.

So... any clue how to fix this?
Basically, you print too hot (and fast) without enough cooling. The deformed small pin in your image is a perfect example of depositing new layers onto too hot (not cooled down enough) prior layers.

You can easily solve this by printing two identical parts spaced apart from each other. This allows the layers to cool before the next is deposited. 

From mastering Ultimaker Cura:


  When printing a series of small parts, print them all together. The
  travel time between the parts is often enough time for the layers to
  cool without changing your settings.


If you do want this to print as a single piece, you need to:


tune down hotend temperature (use the minimum temperature that gives good print results, printing a temperature tower will help to determine this), 
increase minimal layer time (may not always work as speed will not be lowered under the minimum printing speed) and
increase part cooling fan percentage (or print a better fan duct that allows for more cooling air to reach the print; many fan ducts are too convergent, the pressure increase is then too big for the fan to effectively push air through it).