The screenshot shows the speed changes if I leave the speed at the default 200mm/s for external walls. If I reduce the speed to 60mm/s I get less speed changes but still some occur which I can’t explain.
I’m printing in AzureFilm PETG
Bambu P1S 0.4mm nozzle
Speed changes are to help get more uniform and controlled results without prints taking extremely long times. Going slow helps overhangs form better without pulling filament away from the model. It gives time for filaments to melt together or minimize the time spent in non-critical things like infill.
The speeds for different kinds of printing are optimized to be as slow as they need to be and as fast as they can be. The slicer recognizes the different kinds of printing across the model and sets speed accordingly.
Without changing speed you’d be stuck at the slowest speed necessary for the whole print and printing would be much slower.
Hi MZip. Yes I understand areas such as overhangs and bridges will have speed changes, but in this model the speeds are changing at different parts of the corner posts. These posts have a consistent profile throughout, so I wouldn’t expect a speed change to happen. The speed change also seems to be quite dramatic in some areas such as near the base of the posts
Sorry - missed that. No answer on those changes. The Studio software has quite a few bugs in it though so maybe you’ve found another one…
No worries. Thanks for the response anyway
Is that just an indication of speed ?
and which parts are effected by the changes , you appear to be changing filament at some of the changes ?
The slicer assumes you always want the print to complete as quickly as possible, so it works to achieve the highest speed it can on each extrusion path. And since “speed” requires acceleration (and deceleration), how fast it ultimately goes depends on how long the current extrusion path is (the extruder has to slow down for corners, and obviously it has to stop extruding for moves). So speeds will be variable depending on the “topography” of the model.
If you want more uniform speeds, you can’t make slower stuff go faster relative to the stuff that’s already fast, you have to reduce the maximum extrusion speed to a low value to limit the faster portions to a lower speed. Reducing acceleration instead would have a similar effect, limiting the maximum speeds more than the slower speeds.
You can disable that in your Filament Settings, though. I was experiencing issues with bulges and suspected that speed changes were the cause, as they occurred at high-speed change gradients. Anyway, the Path to that box: Filament Editing Symbol > Cooling > (Under Part cooling Fan) Uncheck “Slow printing down for better layer cooling”
was that your point?
Do you have “Independent Support Layer Height” enabled? Then you could occasionally be hitting the “Minimum Layer Time” Filament Speed limit, drastically slowing down individual layers in a seeimingly inconsistent manner.
Check the minimum time for each layer in the filament settings.
A short layer will include a pause to allow cooling before the next one goes on top of it, and the slicer is only showing the average time including the pause. (EDIT It’s the “layer time” in the cooling settings).
Yes it’s indicating speed changes. No there are no filament changes. This is all printed in PETG
