Keywords arithmetic in Cura

[0scar 4]

I'm aware of the availability of keywords that can be used in G-code that are parsed by Ultimaker Cura on compiling the G-code file.

 

I'm missing a good reference how you can do some basic arithmetic to parse a formula to a value rather than an in-place substitution. E.g. in Slic3r you can use some complex arithmetic and conditional statements to define custom values.

 

In defining a certain speed (in mm/min) based on a travel speed (in mm/sec) in end or start G-code one might to use something like:

 

G1 X0 F{speed_travel}*60*0.75

 

How would you implement this in e.g. an Ultimaker Cura "end G-code" to expand to G1 X0 F5400 (for 120 mm/sec travel speed that is)

 

[ahoeben 1,948]

19 minutes ago, 0scar said:

I'm missing a good reference how you can do some basic arithmetic

 

Here's the best reference I can do:

 

"It is not possible to do arithmetic in gcode snippets in Cura"

[0scar 4]

That is definitely an answer! And a great reference for those who seek the same.

 

I guess this should all be done in a post processing script of your own.

[GregValiant 1,251]

@ahoeben I was wondering...

My StartUp G-Code has purge lines and they work well with PLA and PETG but they are too fast for TPU on my printer.  I had a thought to add a Keyword to alter the print speed of the purge lines to match the print speed setting in Cura.  It appears that there is none for "speed_print_layer_0" in mm/minute.

The alternative would seem to be adding a copy of my printer definition and altering the StartUp G-Code with the purge line speeds adjusted for TPU.

What I have hard coded is:

G1 F1500...

What I was looking for would be something like:

G1 F{speed_print_layer_0_mm_min} or some conversion from Print Speed in mm/sec to Print Speed in mm/min.

Just out of curiosity - is there a way (besides adding a second printer definition)?

[ahoeben 1,948]

Out of the box, I don't think there is a way to do this.

You could do this by manually editing a profile cfg file. Or you could create a postprocessing script that does the multiplication.

[GregValiant 1,251]

Thanks @ahoeben.  That's what I was thinking.  All-in-all it's easier (for me) to have a second printer installed in Cura just for TPU.