My printer took 17 hours to print this at 0.200 mm layer height. It is a good test for stringing - if your printer can print this with few or no strings across the holes you are in good shape.

I used the WeaverBird add-on to Grasshopper to design this (which is why the STL file is named wb3.) The part has a circular top and bottom, but in the middle it is a 7-sided equilateral polygon.

This part s a good test for slicers - Simplify3D added solid fill layes in several places, so I did not even try printing that one. Kisslicer sliced it OK, but the end result had a lot of strings, both across the holes and across the inside diameter. Craftware was the best; it produced minimal strings that were easily eliminated with a hair dryer.