Why is slic3r choosing to print slowly?
I've set all of my speeds to 0, hoping to let the volumetric limit reign everywhere. Yet it doesn't seem to be, and I can't figure out what actually is setting the speed. Check it out:
Looks like a volumetric speed limit (e.g., everything is the same). See the attachment.
Yet the speed doesn't look like it matches. I don't understand how you can go 16 mm/s in the infill and 62 mm/s in the perimeters and have 2.73 mm^3/s flow rate in both places. Yes there's infill overlap and all of that, but it's not 4x - that's crazytalk.
Further, 2.73 mm^3/s isn't the flow rate limit. This is the default PLA profile and the volumetric limit is 15 mm^3/s.
So what's going on? I can only imagine that there's a gross math error in slic3r, but maybe I'm missing something.
Re: Why is slic3r choosing to print slowly?
Can you do an export config and post the file? Without seeing your settings, it's awful hard to suggest anything. Did you check both filament and print settings max volumetric speeds?
I personally leave the Prusa default speeds but cap them using the various max volumetric speed settings. That way, speeds become "up to" limits but volumetric calcs throttle as needed.
Re: Why is slic3r choosing to print slowly?
I'm not sure if this is the right config export. If not, please let me know what would be better.
Re: Why is slic3r choosing to print slowly?
I loaded up your settings and got the same results when slicing test models. Speeds and volumetric levels remained at the low end. I tried adjusting Print Settings->Speed->Autospeed (advanced)->Max volumetric speed from your setting of blank to the max E3D V6 limit of 11.5mm^3/s, but this yielded no change.
Next I populated the speeds with those I use for detail prints, and max volumetric speed set to 11.5:
This allowed printing at speeds up to those I'd set:
While keeping overall volumetric throughput at or below 11.5:
I adjusted max volumetric speed to 6:
And again higher speeds could be hit:
So long as the max volumetric limit was maintained:
So it seems you can use max volumetric speed, either in print or filament settings, as an overall limiter up to the set speeds but there need to be set speeds for best results. This is how I have been using it.
I noticed that not all of the speed settings offered a 0 setting, so I set values for those that didn't:
This resulted in some weird speed allowances, but only at lowest layers:
And correspondingly weird volumetric limits, also at lowest layers:
This isn't what I expected, nor can I explain why these results occur, so I'm chalking it up to "unknown behavior" if using 0 for speeds. I realized partway through that my STL isn't level on the bottom, but I was too far along to switch.
I'm using the max volumetric speeds with set speed maximums with good results in any case. I usually set Autospeed->Max print speed to 200, but that can also be used to cap the other speeds. Between max volumetric speed and max print speed, I have pretty granular control without having to adjust individual speeds for each feature. I set a max overall speed of 60:
Notice speed are capped (though not at 60 - not sure...):
While we can still extrude up to maximum rates:
Those 2 settings seem to give a "throttle and clutch" 2 pedal mechanism, while the 0 speed settings seem best suited for use as absolute maximums for specific features.