Homing Z after power failure and mesh compensation offset

modl

Hi everyone

When resuming after a power failure i notice a slight layer offset in z (too high generally. At the start of a print I will home Z with the probe then set the Z max limit thanks to a max endstop

;update Zmax endstop position
echo "Looking for Z max..."
G91
G1 H3 Z400 F600
G1 H2 Z-5
G1 H3 Z10 F{global.probingSpeed}
G90
M500

So after a power failure the routine is to home x and y normally then home Z with the Z max endstop . My question is:
If i probe the bed at X155 Y500 (middle of the bed), does it make a difference regarding the mesh bed compensation if I home Z max at a specific X Y position ? i.e. should I also home Z max at X155 Y500 ?

; homezmax.g
; homing Z using the max endstop
G4 P10
echo "Homing Z max..."
G4 P10
G29 S2
M290 R0 S0                 ; cancel baby stepping
G1 H1 Z5
G1 X10 Y10 F5000   ; move slightly away from the 0s
G91

G1 H1 Z400 F600
G1 H2 Z-5
G1 H1 Z10 F{global.probingSpeed}
G1 H2 Z-10 F600
G29 S1
G90

Thank you in advance

Phaedrux

@modl said in Homing Z after power failure and mesh compensation offset:

If i probe the bed at X155 Y500 (middle of the bed), does it make a difference regarding the mesh bed compensation if I home Z max at a specific X Y position ? i.e. should I also home Z max at X155 Y500 ?

Well yes, you may get some variance from thermal expansion which changes over the course of the print.

Have you tested homing with the probe and then setting the Zmax position and then testing that the nozzle actually touches the bed at Z0?

modl

@Phaedrux Thank you for your reply, I haven't tested that it's a good idea, will do after the current print is finished (about 12days...)