Cura

I had issues when loading up GCODE to OctoPrint.  It told me that I'm still using travel_speed instead of speed_travel.

I found out this code was in the start and stop section of the slicer.

To change this, open Cura and select Settings -> Printer -> Manage Printers...

The printer you're using should be highlighted, select the Machine Settings button.  You will see the start code on the left and the stop code on the right.

Search in the start/stop code for {travel_speed} and replace it with {speed_travel}.

After closing all the dialogue boxes, reslice your model and all should be fine if you import the .gcode file into OctoPrint.

By default, the Cura slicer will generate the following entry code before it takes the start-up code which you can manipulate:

;FLAVOR:Marlin

;TIME:15011

;Filament used: 18.883m

;Layer height: 0.3

;Generated with Cura_SteamEngine 3.4.1

M190 S55

M104 S200

M109 S200

M82 ;absolute extrusion mode

;Sliced at: Mon 16-11-2020 18:52:54

;Basic settings: Layer height: 0.3 Walls: 0.8 Fill: {fill_density}

;Print time: 04:10:12

;Filament used: [18.88]m [56.31953578125]g

;Filament cost: [0]

;M190 S55 ;Uncomment to add your own bed temperature line

;M109 S200 ;Uncomment to add your own temperature line

G21        ;metric values

G90        ;absolute positioning

M82        ;set extruder to absolute mode

M107       ;start with the fan off

G28 X0 Y0  ;move X/Y to min endstops

...

The orange part is the entry code, the blue part is the (start of the) start-up code which you can modify as explained in the above chapter.

However, there's a drawback to the entry code generated by Cura: before heating up the hot end (a.k.a. the extruder), it waits until the bed has reached its wanted temperature.  Only then, it will execute the next command and start up heating the hot end.

The reason for this is that Cura generates the codes M190 and M109.   What do those codes mean?

• M190 S55 means: heat up the bed to 55 °C and wait until it has reached its temperature before moving on

• M109 S200 means: heat up the hot end to 200 °C and wait until it has reached its temperature before moving on

So, that's the reason why, when you start a print action, the sequence is not continuing to heat up the hot end before the bed is heated up.

There are other commands in the G-code standard that to not wait for something to reach its temperature:

• M140 S55 means: heat up the bed to 55 °C and continue with the next command

• M104 S200 means: heat up the hot end to 200 °C and continue with the next command

So, the best thing would be to change the start-up code and modify the heat up parameters for both the bed as well as the hot end.

However, since the entry code comes before the start-up code, how can we influence that?  Is it not that the entry code will anyhow wait until the two temperature have been reached?

Well, it seems that, if you modify the start-up code and add the following commands, the Cura slicer will detect this and as a result will not generate the temperature settings in its enty code!

Code to be added in the start-up code:

; Added by GVC

M140 S{material_bed_temperature_layer_0} ;Start heating bed

M104 S{material_print_temperature_layer_0} ;Start heating extruder

M190 S{material_bed_temperature_layer_0} ;Wait for bed to reach temp before proceeding

M109 S{material_print_temperature_layer_0} ;Wait for extruder to reach temp before proceeding

; End added by GVC

As you can see, the first two commands are the ones that set both bed and hot end temperatures, without waiting for each other!  Obviously, once the temperatures are set, we do have to wait until both have reached their setpoint.  That's obvious.  But since the first wait is for the bed to reach its temperature, the hot end will have reached its setpoint already by the time the check is executed, since the hot end is heating up much faster.