How can I make startup GCode that depends on the nozzle diameter?

[NameOfTheDragon 0]

Hi everyone. I've tried looking in the online guides for this but I can't seem to find anything. I'm using Klipper firmware and I want to set the pressure advance based on the nozzle diameter. Is that something I can do in Cura? Basically what I need is a case statement, or if-then-else. The gcode I need to add is:

 

SET_PRESSURE_ADVANCE ADVANCE=n.nnn

For a 0.4mm nozzle the value should be 0.153, for a 0.2mm nozzle it's 0.250, etc. The values are determined by printing a calibration tower and they are different for every nozzle size and in some cases per filament. In Prusa Slicer I've done it like this:

{if nozzle_diameter[0] == 0.2} SET_PRESSURE_ADVANCE ADVANCE=0.250
{elsif nozzle_diameter[0] == 0.4} SET_PRESSURE_ADVANCE ADVANCE=0.153
{endif}

I imagine there must be some similar technique in Cura, Can anyone point me to the right documentation or an example, please?

Edited August 29, 2020 by NameOfTheDragon

[ahoeben 1,948]

Use the Linear Advance Setting plugin (from the Marketplace) to set your linear advance factor in profiles. Then - since you seem to be using Klipper), add this gcode macro to your printer.cfg:

[gcode_macro m900]
default_parameter_K: 0
gcode:
  SET_PRESSURE_ADVANCE ADVANCE={K}

 

[benspawn 1]

Not sure if have this figured out yet but I do something similar except for different extrusion widths when I was running Marlin. Just changed over to Klipper now and figuring out how I can do the same so still looking into an elegant solution but for the moment I use post-processing in Cura to set my K values

Basically in my start gcode in Cura I have:
M140 S{material_bed_temperature_layer_0}    ; Start heating the bed to initial layer temp
G4 S30                    ; wait 30 secs
M104 S{material_print_temperature_layer_0}    ; start heating the hot end to initial layer temp
M190 S{material_bed_temperature_layer_0}    ; wait for bed
M109 S{material_print_temperature_layer_0}    ; wait for hotend

In Search and Replace with the checkbox for expressions ticked I do the following
Search: M190 S85.1\t; wait for bed\nM109 S225\t; wait for hotend
Replace: ;POST-PROCESSED DETAIL PETG 0.2_0.42\nM190 S85.1\t; wait for bed\nM109 S225\t; wait for hotend\nM92 E414.63\t; set new extruder setting for PETG\nM301 P14.19 I0.81 D62.17\t; set PID hotend 230C/50% fan\nM304 P114.31 I19.93 D437.00\t; set PID bed 85C\nM900 T0 K1.635 L1.72\t; Linear advance for DETAIL PETG 0.2_0.42

And then in my specific Cura profiles, I just make sure to set the initial bed temperature to 85.1 (or whatever else triggers you use) so that it will trigger the search and replace code that I want. I also use this to set my extruder E steps, as well as PID settings. Because I have my PID values, and E-steps tuned for whatever setting that I'm using (PLA or PETG etc).

 

So in the end I have about 15 different Search and Replace code to handle the various settings that I have. All hinging on this initial bed temp value.

I even use this Search and Replace method to set different K (and L) values when I'm doing a different initial layer height for example. Bear in mind this was all for Marlin, so you'll have to modify the code to your needs.

 

[mardocheo 0]

On 8/30/2020 at 12:58 AM, NameOfTheDragon said:

Hi everyone. I've tried looking in the online guides for this but I can't seem to find anything. I'm using Klipper firmware and I want to set the pressure advance based on the nozzle diameter. Is that something I can do in Cura? Basically what I need is a case statement, or if-then-else. The gcode I need to add is:

 

SET_PRESSURE_ADVANCE ADVANCE=n.nnn

For a 0.4mm nozzle the value should be 0.153, for a 0.2mm nozzle it's 0.250, etc. The values are determined by printing a calibration tower and they are different for every nozzle size and in some cases per filament. In Prusa Slicer I've done it like this:

{if nozzle_diameter[0] == 0.2} SET_PRESSURE_ADVANCE ADVANCE=0.250
{elsif nozzle_diameter[0] == 0.4} SET_PRESSURE_ADVANCE ADVANCE=0.153
{endif}

I imagine there must be some similar technique in Cura, Can anyone point me to the right documentation or an example, please?

SIMPLE IS THE BEST:

 

[gcode_macro m900]
gcode:
  SET_PRESSURE_ADVANCE ADVANCE={params.K}

[mardocheo 0]

[gcode_macro m900]
gcode:
  SET_PRESSURE_ADVANCE ADVANCE={params.K}

[boztech25 0]

WRONG Haha. Try this instead

 

[gcode_macro m900]
gcode:
  SET_PRESSURE_ADVANCE ADVANCE{params.K}