The slicer flow rate settings are often ignored

CBX_Micha

... yeah yeah yeah... me again... :(

If I specify flow rates other than 100% in CURA or ORCA (often 97% for the first layer, then 95%; depending on the material), this flow rate is not adopted by the server in what feels like 70% of print starts. It stays at 100% and I then have to intervene manually.
Strangely enough, sometimes it works, but despite intensive searching, I just can't figure out under what circumstances it works and when it doesn't.

Is that just me?

Repetier

You mean slicer adds M221 Sxxx to change flowrate?

Despite the fact that on connection start we set it to 100% we do not block it. Except if at some point firmware says M221 is not supported after that we would filter M221. You can send M221 any time and we even show the correct flow rate.

CBX_Micha

OK, you're right. If I set it up manually in the terminal, it works too.
I've now sliced something simple in CURA. In CURA it is set that the first layer should be printed with 95% and all other layers with 90% flow rate. I saved that as a gCode and searched for M221... Nothing... nada...
So this seems to be a BUG or a setting issue in CURA. Because as I said: sometimes it works

Repetier

How did you say this? Slicern normally do not use M221. Instead they compute the E values by multiuplying 100% value with extrusion rate set in filament settings. Simply because M221 is not meant for slicers - it is to adjust later in print in case slicer settings were too low for your current fileament e.g. because it has a slightly different diameter.

CBX_Micha

Ok, if that's the case, then I can't tell during a print which flow rate is currently active... That's uncool... And why does it sometimes work (it feels like every 10th print) that on the RS display are 95% or 90% is displayed? Where does that come from then?
Now I'm more confused as before ...

Repetier

I only know a case in PrusaSlicer where they add a M221 for a special condition if layer height is 0.1mm or lower. Mut that is visible in the start g-code in slicer for that config. So maybe you have it as well somewhere for some conditions?

Also note that we do not reset it once it was changed it stays until someone sends a different value.

CBX_Micha

Ok, ty for you help. I'll research this further. With your explanations I can at least rule out certain things...