Cura and its estimated print time

CapFive

Hello all!

I'm using Cura 4.7.1 as my slicer of choice for my A5S.

I have noticed with the prints I've been making, the print time Cura estimates is WAYY off from the actual print time as indicated by the printer itself.

I understand Cura's time is an "estimate", but I've had prints run two-three hours longer. In fact, the one print I am running right now has a Cura estimate of 7 hours 21 minutes. As I'm typing this, my printer has been going 10 hours 43 minutes with 26% of the print remaining.

I'm going to print a different model after this to see if the difference in the time is proportionally consistent. That should help me get a more accurate run time for each print.

Has anyone else noticed this? If so, have you figured out why?

I've Googled this and found some posts in the Ultimaker forum saying improvements will be made in future versions of Cura to have more spot-on estimates. The future version they were speaking of was version 2.3.

I guess they're still working on it...

CapFive

I decided to generate Gcode through Slic3r.

Through Slic3r, I created a profile for my A5S. That also gave me a 7 hour estimated time. (7 hours 17 minutes, to be exact.) And the material costs were almost identical.

So that tells me there's some process or mechanical aspect on the printer itself that the slicing software is not accounting for in its estimates.

The experiments continue...

Samuel Pinches

Hi @CapFive , the main inaccuracy is the acceleration settings of the printer, which are different to what the slicer assumes. You can enter the actual acceleration settings into cura, and then you should get a more accurate estimation.

CapFive

Hi @Samuel Pinches... thanks for the follow up.

I'm a bit confused. Wouldn't the printer operate at the settings specified within the slicer regardless if it's a default value or an override?

Samuel Pinches

Yes, exactly. However, acceleration settings are not normally specified in G code from most slicers.

The acceleration settings are normally printer specific, so the slicer assume is it supposed to leave them as the printer defaults are. 

If you want to print at acceleration settings that are too high, you can damage the printer, or cause a poor quality print. 

CapFive

Ah... I guess I'll have to look up the acceleration specs for this printer.

And I have tried printing at high acceleration settings. Not pretty... haha!