And nozzle height is very difficult tachieve : each time I begin to print I have (using Machine3D PLA mat)there is always a lot of pla extruding first , that doesnt look very precise. Should I use the plastic card packed with the printer to calibrate or a piece of A4 paper ?
If I change the board an put the glass one generally I obtain airprint, or if a recalibrate the whole thing, a non sticking thing.... I know this can be an excellent printer but Now I am experiencing somme difficulties.
In upstudio you can click each corner on the calibration screen to move the hotend to each corner. Level the bed by moving it up and down using the software controls on the printer itself, then using the feeler card adjust each corner till it just rubs between the nozzle and heatbed.
The once the bed is mostly level, you can do the normal software level routine. I've done this and the autolevel says my bed is level to within 0.12mm.
Maybe be a useful reference? https://www.youtube.com/watch?v=uPCjYC-ZVwE