Better 3 axis calibration cube

thingiverse

This precision 20mm XYZ calibration cube takes the typical calcube to the next level. Two major issues with traditional calcubes are addressed in this design: 1) Achieving accurate Z-axis measurements is a challenge due to errors from squished first layers or uneven raft surfaces. 2) Over- or under-exposure can cause all dimensions to grow, resulting in an offset rather than a scale error. This error compounds when measuring two outside edges, leading to incorrect scale corrections. This cube eliminates these issues by using a caliper/micrometer depth gauge for measurements, eliminating overexposure errors and allowing for more accurate readings. The Z-axis reference surfaces are also designed not to touch the bed or any supports, further reducing potential errors. A 34mm circle is cut into the bottom 10mm of this cube, providing a convenient feature for checking XY squareness by comparing opposite corners with the jaws.