G29 command before hot end heated up?

[wd40 0]

I would like to have the G29 (bed leveling) command sent to the printer before the hot end on my printer is heated up.  But CURA seems to heat up the bed and the hot end before any custom Gcode is sent for a print job.

 

Is there a way to customize the Gcode CURA sends before heating up the hot end?  The only way I can do it presently is to edit the Gcode manually after CURA generates the Gcode.

 

Thank You

[wd40 0]

Nevermind.  I think the answer is essentially provided here: https://community.ultimaker.com/topic/26391-start-heating-bed-and-extruder-and-level-bed-at-the-same-time/

 

[nitro2k01 2]

Doing G29 before heating the bed and nozzle is a bad idea. Things expand when they are hot, so the readings will be slightly off when the print starts. If the objective is to save some time, it's not a bad idea to start heating the nozzle and bed simultaneously, assuming your power supply can handle the extra load for a couple of minutes. 

[wd40 0]

Agreed that heating up the bed before G29 is important due to thermal expansion.  But the hot-end never touches the bed during leveling with the BLTouch, and is therefore not involved during the auto-bed-leveling process.  So no need to heat up the hot-end in advance of bed-leveling.  

 

Of course the thermal expansion of the hot-end might be a factor when determining the correct Z-probe offset for the BLTouch -- but that is pretty much a one-time measurement determined when installing the BLTouch.