Pre-heatup Gcode

[kerog 0]

My printer's firmware has heating commands built into the Z home.  When you do a Z home, it heats both extruders to 120C before actually homing, so that any blob on the nozzle would be soft enough not to mess things up.  This interferes with Cura's initial heat code, which goes before the starting gcode from the printer.  What happens is that Cura heats things up to the set point, the Z home in the starting code then takes the temperature down to 120, and then I have to heat it up again.  It would be nice if you could either (a) turn off the initial heating gcode (and then add it back in as part of the startup gcode), or specify special gcode to run before those initial heating commands.

 

I can work around it by taking the G28 out of my startup gcode and making sure I manually home all before each print, but that's a pain.

 

If anyone knows of a better workaround, I'd like to hear it.

[ahoeben 1,849]

Cura looks at your start gcode, and does not see you heat up your extruder(s). It then figures that extruding cold probably isn't a good idea and adds the preheating sequence before the start gcode.

 

Try adding the following line to your start gcode (anywhere):

;M104 {material_print_temperature}

Add the line EXACTLY like this; with the curly braces and the exact text (don't substitute it with the number).

Note that I have put a ; before it, so it will not actually be executed. But it is enough to convince Cura you are doing something to heat up your nozzle, so it will not do it for you.

[penright 0]

Been googling on the subject of preheating. So far I  have been using "Target" on the temperature tab. I see there is a "Preheat Button" plug-in. I am really new to Cura and 3D printing, so some of my assumptions may be way off. Looking at the code of the "Preheat Button" looks like it just plugs in the values into the current page. I was looking for something more intelligent. So when you click on print, if needed then the preheat process would start, and when finished, then the printing would start.

Can I do it with the "start gcode"? Can the gcode be smart enough to wait for a time? Can that time be variable or maybe just wait for a time once the temperature is reached?

[A2k 0]

@penright If you found the solution to this I would also like to know since the latest Cura doesn't seem to be preheating my UM2 automatically before I send a print via USB