Swiss Cheese Calibration Cube

(UPDATE 2/3 - I updated this file to clean up some manifold errors. The previous version prints just fine; it gave some errors on some slicers but still printed. The previous version has been replaced with this one.)

The ultimate calibration and tolerance test cube. I present the Swiss Cheese Calibration Cube or SC³.

This model is designed to assist you in calibrating your printer in all three axes and assist you in printing within the accuracy of many models built around popular screws, nuts and fasteners. I based many of the tolerances around Voron standards and ABS/ASA, but this cube will work with PLA and PETG as well.

Please Note: 
Two files are included, stl and obj. Prusa Slicer will not error on the OBJ files but will auto repair the STL file and still print.  You may get a stability warning; this is the bridging parts. Ignore the message and do not print with any support to ensure you stress test your printer properly.

This cube has several holes in it for testing popular things like:
6x3 Magnets
.1 and .2 tolerances (.1 tolerance is ideal for testing PLA and PETG specifically)
4mm Allan Tool tolerance (ASTM socket of 4mm, tool of 3.95mm - tool or print variations may affect if this can fit or not)
SHCS M3 Screws - Countersink, passthrough (3.2mm) and self-tapping (2.9mm)
Filament passthrough - 2.2mm
Heat Set Insert M3-5x4
M3 Nut

Test all the holes to see how your printer stacks up and make adjustments to get closer to tolerances. Do not worry if you're ‘close enough’; as a standard cube, you can test for dimensions, layer quality, corners and resonance. I recommend starting with those basics first before moving on to your slicer to tune it further for tighter tolerances. 

The self-tapping holes will be found paired with all the M3 Nuts and all the Heat Set holes. 2.9mm was chosen over 2.7mm, so this way, even if it is out of tolerance, you have a little bit of room to still test the heat sets and M3 nuts. If it really tight, forcing it on the X and Y axis will likely separate the layers, so expect that you need to make adjustments to compensate for that. 

Print Settings
2-3 perimeters/walls/top/bottom
.96 extruder multiplier/flow to start
10-15% infill
Seams - aligned

How to calibrate
1) Tune your belts, screws, wheels, bed springs, etc on your printer
2) Print or estimate optimal printing temperature and flow
3) Print this cube to get a benchmark of what needs to be done - Filament passthrough is the largest margin of tolerance at .45mm of tolerance. If your filament is super tight going through any of the passthrough holes, then adjust your flow/extruder multiplier
4) Check for bridging problems in the lower tolerance holes and adjust cooling as necessary. This is also a good place to check for stringing/retraction. Aligned seams will also show separation if your retraction is too high. Adjust retraction settings and lower printing temps to reduce stringing.
5. Make all necessary adjustments and test again.

For comprehensive tuning, I recommend the Ellis tuning guide. The link is found here:
https://ellis3dp.com/Print-Tuning-Guide/

ASA/ABS tolerances should be just perfect with this cube. PLA and PETG will feel a little looser, and the self-tapping should just bite a little. If it doesn't bite enough, then your flow is too low or you're underextruding. If it bites solid, use the tolerance part to check all the .1 sections to see if it fits well. If it doesn't fit or is very tight, your flow needs to be adjusted to be lower.

For questions or help you can also find me (Kinematic Digit) on discord on this server:
https://discord.gg/x6CPZhYHkY

One final note. I have had some responses back to me that made people doubt their tuning abilities after printing this cube. I designed this to challenge the printers but did not intend to make people feel inadequate. It is important to understand that fine-tuning things is just as much an art form as a science. Your degree of success will vary, and I think it's important to set realistic goals when calibrating. Aiming to get smooth surfaces, good tolerances, sharp corners, eliminate ghosting, etc.… are all individual levels of tuning, so do yourself a favour and focus on one at a time :)

Thanks for your support, and Happy Tuning!