Homing while heating?
I see in the custom gcode for my i3 Mk3S that the printer waits to home until after the bed and nozzle finish heating. Is there a technical reason for this, and would it be inadvisable to swap the ordering of the home and wait instructions so that it can home and do mesh bed leveling while it is heating up? If the concern is that the heat of the nozzle may damage the bed, could I just raise the Z axis by say, 5mm?
RE: Homing while heating?
You want to heat up first because all the parts expand or will move slightly in relation to each other as they get up to temperature, so the results you get before warming up won't be correct for the actual print.
RE: Homing while heating?
@with_maltodextrin
I figured it was something like that. Ah well, it still heats pretty quickly. Thanks for your help.
RE: Homing while heating?
If you have any nozzle ooze, homing without warming the nozzle can cause hard filament to be driven into the print surface. The default startup gcode simply warms the bed and nozzle at the same time and waits for both to hit final temps before proceeding with homing. Many of us get better results with a multi-step warmup procedure as follows:
- Start warming the bed.
- Start warming the nozzle to a temperature at which filament will not ooze out during mesh bed leveling, but will be soft enough not to cause damage from any ooze when homing.
- When the nozzle hits a no-ooze temperature (I use 160C), do homing.
- Wait for final bed temps and nozzle temp.
- Proceed with printing.
I've got a fully documented example of startup gcode here that you can look at for ideas. I some other steps, including waiting for a consistent 35C PINDA temperature and bed warmup before mesh bed leveling.