Prusa i3 mk2s calibration squares by jjisnow

Last crawled date: 3 years, 1 month ago

Since other printable calibration squares wouldn't give me the control I needed over my calibration, I decided to publish my own version.
The Prusa i3 mk2s allows you to control bed level in multiple ways.
Firstly, the mesh bed level gets you close to correct level - This will be perfectly sufficient for beginners
Second, the live Z and the prusa test print and watching for 'squish' gets you closer to level.
Thirdly, the bed level correction allows you much finer control ( I find to within about 30 microns accuracy) over the first layer level of a print.
Step 1
After obtaining the file, check from previous prints whether the centre of the printbed is level. You can delete the outside squares and print the central square only if this helps. By level, I mean too high = gaps start appearing between infill lines and too low = blobs and smears appear on the top layer as the nozzle is driven through the plastic .
Step 2
Print the 5 squares.
Step 3
Adjust the bed level in LCD menu Calibration->Bed Level Correction in steps of up to 20 microns (0.020mm) until the same appearance occurs in the other squares. This allows up to 50 microns of adjustment
Step 4
If needed, Adjust the Gcode in Slic3r, Printer Settings tab->Custom G-code->Start G-code box so the G80 line includes your bed level corrections.
eg G80 L20, R-10, F60, B40; mesh bed levelling
G80 = mesh bed level
L20 = raise nozzle above heatbed on the left side of the bed 20 microns
R-10 = lower nozzle towards heatbed on right side of the bed 10 microns
F60 = raise nozzle above heatbed on the front of the bed 60 microns
B40 = raise nozzle above heatbed on the back of the bed 40 microns
You can gain up to 100 microns of adjustment here, above which the printing software will simply throw an error and print with 0 microns of adjustment.