Variable FLOW depending on speed VFR (question/feature request)
I have 4 different printers and all of them share the same drawback (actually I think all existing FDM printers struggle from this)
Problem is when you are reaching reasonably high Volumetric Flow Rate, your flow starts to drop down. I think all of us met with this. Is there a way to add some increase of FLOW depending on current VFR? Or is this a good idea to implement?
P.S. It is a bit better to implement this in printer firmware, and there was such a feature request in Klipper groups 5 years ago, but no one did this. And by my opinion this is VERY much needed 🙂
RE: Variable FLOW depending on speed VFR (question/feature request)
That's a good point! You often run into this problem with FDM printing. It is a good idea to change the FLOW variable based on the VFR to make up for flow restrictions. Putting this into practice, especially in software, could make print quality and speed a lot better. Given the demand, it's strange that this isn't used by more people.
RE: Variable FLOW depending on speed VFR (question/feature request)
Thats what the Max volumetric flow settings in the slicer are for. You have to determine from testing what your particular hotend/filament combinations maximum it can provide is. Once you know that value, which is determined by your hardware limitations and the type of filament (and the print temperature) used so its not something you can 'go over' then the value gets plugged into the slicer, either in the filament profile or the print profile (lowest value is the one the slicer uses).
At that point even if your speeds are set stupidly high the slicer wont issue commands to try and print ore than the printer can realistically do. Most people dont test to see what their printer is capable of and just relay on the general ones in the filament profiles, at least for Prusa Printers.
Plenty of youtube videos on how to determine your printers max volumetric rate.
RE: Variable FLOW depending on speed VFR (question/feature request)
While I use VFR limitation and it solves some problems, it is very far from what I need/mean 🙂
The problem is that one print can have a VERY different VFRs, and therefore for example at 3-4 mm3 (small perimeters) you will have a well calibrated print, and on 10-15 (infill / perimeters) your FLOW will degrade a LOT and you will have underextrusion.
With manually changing the FLOW ratio you can fine-tune some prints, but it is not accurate for complex scenarios. (I mean not super complex - just a scenario when speed/vfr is very different in just one print)
Thats what the Max volumetric flow settings in the slicer are for. You have to determine from testing what your particular hotend/filament combinations maximum it can provide is. Once you know that value, which is determined by your hardware limitations and the type of filament (and the print temperature) used so its not something you can 'go over' then the value gets plugged into the slicer, either in the filament profile or the print profile (lowest value is the one the slicer uses).
At that point even if your speeds are set stupidly high the slicer wont issue commands to try and print ore than the printer can realistically do. Most people dont test to see what their printer is capable of and just relay on the general ones in the filament profiles, at least for Prusa Printers.
Plenty of youtube videos on how to determine your printers max volumetric rate.