Feed rate and Flow rate

My CR10s Pro has a control for increasing the print speed while printing. From searching the info here it seems that the Feed rate and Flow rate controls on the Control tab are used for this in Octoprint.
If I understand correctly, Feed rate controls the speed of movement of the head and flow rate controls the rate of flow of the filament.

So, firstly, have I got that right and secondly does increasing the Feed Rate automatically increase the flow rate to suit? e.g. if my head is moving 25% faster it needs to extrude the filament 25% faster to keep the same print density.
If not, I assume I need to adjust both in syncronisation to keep the print good?

Thanks in advance


What is the problem?
I'm trying to understand changing the speed of printing using the Feed rate and Flow rate controls on the

What did you already try to solve it?
Searched the FAQ and forum.

Logs (octoprint.log, serial.log or output on terminal tab at a minimum, browser error console if UI issue ... no logs, no support!)
None relevant

Additional information about your setup

OctoPrint 1.4.0 running on OctoPi 0.17.0
On a Pi 4B controling a CR10s Pro

The feedrate affects the speed of the print.
The flow rate affects how much material (in total) is extruded.

If you increase the speed at which the X & Y axes move, the speed at which the extruder motor moves also increases. But the same amount of material is extruded over the same distance.

If you increase the flow rate, the speed at which the X&Y axes move is not changed.

In theory, no, you should not adjust both in synchronisation. The firmware takes care of that. In practice, it might be beneficial to ever so slightly overextrude if you go much faster than normal. Or underextrude, depending on your printer and the material used. Test and tweak.

1 Like

Question: Does the Feedrate as seen in the Control tab affect all axes to include the extruder?

I may be doing it wrong but in the past when printing with flexible PLA I might set Feedrate to 95% and then set Flowrate to 105%. My assumption would be that the first would have also affected the extruder (bringing it down to 95% of the gcode file's value) and then I would add another 5% to that so that it would try to compensate for expected feed gear slippage.

  1. Feedrate = 95% + Flowrate = 100%
  2. Feedrate = 95% + Flowrate = 105%

Assuming that you wanted to slow things down and compensate 5% for slippage, which of the above would be the correct way to go?

I am far from the leading expert on flow rates; I am just applying logic.

You should use the setting that works best for the combination of printer, filament and model. Each of them affect the print quality. Flexible materials are a very different thing to print than normal, non-flexible materials.

I don't think there is a linear cohesion between extrusion speed and slippage, so there is no linear rule of thumb between feedrate and how much you would have to compensate for that. But in my opinion the flow rate is not the right tool to compensate for it in the first place. The flow rate only affects the speed of an extrusion. If the extruder is slipping, that might indicate you need more force. Just pushing more material will only get you more slipping. Worse still, often stepper motors have less force when they move faster. You may get more extrusion (so, overextrusion) in parts where the the extruder was not slipping.

You may get better prints with the 95%/105% mix. Or worse prints. But not as a rule.

If you get serious amounts of slippage after adjusting the feedrate, I would suggest you dial back that feedrate adjustment.

I find that the 95%/105% works for this particular filament. I guess I'm trying to decypher why it works. I'm guessing that it's doing both of what I'm suggesting (slower with the idea of overextrusion).