Printer loose homed axis at end of a print

Lakko

Hi,
i noticed that at the end of a print it perform an homing for X & Y (as required by the end gcode) but after that it lose all the position and to start another print i have to re-homing all axis.
This is my end G-code:

M104 S0 ; Set extruder temp 0C
G92 E1
G1 E-1 F300
G91 ;Relative
G1 F150 ; slow Z rate
G1 Z15 ; Z up 15mm
G90 ; back to absolute
G28 X0 Y0
M84 ; Disable motor

It is a default setting or it is caused by the M84?

nhof

Yes, the M84 will cause the printer to 'lose home'

You can provide arguments for specific axes like so

M84 E0 ; this would cause E0 to go idle, but not the gantry motors so it will not 'unhome' the machine.

dc42

Just remove the M84 from your end GCode. The motors will go to idle current (default 30% of normal) after 30 seconds of inactivity.

Lakko

Ok perfect thank you

dc42

BTW the reason that we mark axes as not homed when you turn the motors off is that when you power them on again, it's quite likely that they will jump to a new position that is 4 full steps from the one before power off. This is also the reason why dual Z motors tend to get out of sync. Whereas maintaining 30% current is normally enough to hold them in position. Some delta printers need 60%.

deckingman

........ and with no power to hold the motors, it's all too easy to accidentally move a gantry out of position. In fact, simply walking past a cheap kit printer stood on wonky desk can be enough