Inspired by vernier scale, I created this printable scale to measure the XY-offsets for multi-nozzle 3d printing. Theoretically it is able to measure the XY-offsets at 0.05mm precision.
In your favorite slicer, place the two scales on the build plate (along x or y axis). Make sure the zero marks are aligned. Set the main nozzle to print the fixed scale (red one in pic), and the other nozzle to print the test scale. (Yellow one in pic). Slice the file, print it.
Usually just print one layer. Then read the marks to get the offsets in millimeters.
The first digit of the offset can be read from the fixed scale, just read the nearest mark on the left side to the zero mark on the fixed scale. Then digit under the decimal point can be read from the test scale (white one in pics), just read which mark on the test scale has the best alignment with the fixed scale mark.
You can print two pairs of the model to measure X and Y offsets at the same time.
OpenSCAD file is attached. You can change precision, unit ( e.g. 2mm or 3mm per mark) and font (change the typeface variable setting).
Any comments or suggestions are appreciated!
DIY Multi-nozzle Ultimaker