This is just my version of the common 3d printer calibration cube. It features 30 degrees chamfers on the top and bottom of the model to prevent elephant foot issues. I've also rounded all the remaining sides and letter borders to prevent linear advance issues as, in these spots, tiny blobs forms if this parameter has not been calibrated yet.

I've also left a preconfigured .3mf file with the new Prusaslicer lightning infill to reduce print time to less than 50 minutes which for a 40mm cube is not bad at all.

Here are some other print settings of the .3mf file:

nozzle diameter: 0.4mm;

perimeters: 2;

top layers: 3;

bottom layers: 2;

layer height: 0.3mm;

cooling: 100%.

If you're using the included .3mf file you will probably have to look after the “minimum skirt length” as it's set to 120mm for personal needings.

If you're looking for a 20mm cube just set the model dimensions to 50% in Prusaslicer.

Consider that the letters have a 0.5mm rounding so downscaling the model may result in linear advance issues.

I hope that you will find this model helpful.