Calculated settings like 'Travel speed'

[hapklaar 1]

I'm trying to understand how certain print settings are calculated. For example the Travel speed.

 

Travel speed is calculated to be 120mm/s regardless of the printing speed I configured, which is currently 250mm/s, even though the tooltip for travel speed says it is affected by printing speed. I can change the printing speed to whatever I want, but travel speed is not changed accordingly.

 

How can I determine why the travel speed is calculated to be 120mm/s? In addition, where can I find how all the other settings are calculated?

[GregValiant 983]

That isn't how my install of 4.13.1 works.  250 gives me a travel speed of 250 which seems to be a max.  Other than that, I'm seeing 2.5 times print speed up to a print speed of 100 at which point 250 is reached and it doesn't automatically go any higher.

 

What Cura version is that?

[nallath 1,104]

On 2/11/2022 at 2:25 PM, GregValiant said:

That isn't how my install of 4.13.1 works.  250 gives me a travel speed of 250 which seems to be a max.  Other than that, I'm seeing 2.5 times print speed up to a print speed of 100 at which point 250 is reached and it doesn't automatically go any higher.

 

What Cura version is that?

The settings are calculated based on whatever the printer you selected has setup. So every printer can have a different way to calculate the ratios of these settings.

[hapklaar 1]

 

On 2/11/2022 at 2:25 PM, GregValiant said:

That isn't how my install of 4.13.1 works.  250 gives me a travel speed of 250 which seems to be a max.  Other than that, I'm seeing 2.5 times print speed up to a print speed of 100 at which point 250 is reached and it doesn't automatically go any higher.

 

What Cura version is that?

I'm using Cura 4.13.1 as well. Travel speed seems to be totally unconnected to print speed. I have no idea how this is possible.

 

On 2/14/2022 at 10:43 AM, nallath said:

The settings are calculated based on whatever the printer you selected has setup. So every printer can have a different way to calculate the ratios of these settings.

 

The printer settings in Cura don't have an entry for maximum speed, only dimensions and extruder setup. Or should I look for these settings in the raw config files?
 

PS as my printer brand isn't listed I always add it as Custom FFF printer. COuld it be that this type has travel speed unconnected to print speed?

Edited February 20, 2022 by hapklaar

[ahoeben 1,766]

On 2/11/2022 at 1:55 PM, hapklaar said:

How can I determine why the travel speed is calculated to be 120mm/s?

There's an extremely subtle queue in the screenshot. Do you see how the label for "Travel speed" is italicized? That means the value or formula originally set in the printer, quality or material profile is being overridden by a user-defined profile (ie: a profile you created).

 

On a general note, you can get a hint of which settings affect other settings or are affected by other settings by looking at the tooltip of the setting. If there is a setting listed as "is affected by" then the value of the current setting is a formula that references those settings. However this mechanism is not very smart. In this (somewhat theoretical) example, speed_print affects speed_travel, but not in a way that is immediately clear:

 

speed_travel = 120 if speed_print > 20 else 100

 

You would only see the travel speed change around a specific change in print speed.

 

But I guess the tooltip mechanism also does not take into account that you have overridden the travel speed formula in a profile.

Edited February 20, 2022 by ahoeben

[hapklaar 1]

@ahoeben

Interesting. When I go into the profile settings and view extruder settings, I see this tooltip for Travel speed:

 

This suggests it is calculated to be always 120, except when magic_spiralize (I assume spiralize outer contour) is active. This means travel speed is only related to print speed in vase mode. This seems odd 🙂 Is this calculation hardcoded into Cura?

[ahoeben 1,766]

It is not "hardcoded" in the code (as few things as possible are in Cura), but it is the default value as specified in fdmprinter.def.json:

https://github.com/Ultimaker/Cura/blob/master/resources/definitions/fdmprinter.def.json#L3174

Edited February 21, 2022 by ahoeben