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What's with the 95% flow rate?  

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nuggetz
(@nuggetz)
Eminent Member
What's with the 95% flow rate?

Can someone explain why the flow rate is set to 95% in the LCD menu? If I slice something with a flow rate of 100% and print it via SD card, should the flow rate on the LCD tuning menu match or will it always stay at 95%? If it stays at 95%, does that mean that its 95% of whatever flow rate I set in the Gcode? Can someone that knows clear this up please?

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Posted : 11/02/2020 8:36 pm
Rat_Patrol
(@rat_patrol)
Trusted Member
RE: What's with the 95% flow rate?

The Mini's fw matches the flow rate in your slicer settings.

Its not a % of a %, its the same as what was in your slicer. This is handy in that should you find you need to tweak it for a particular filament, you can adjust the setting in PrusaSlicer so you don't have to tweak it manually (setting up a specific filament, of course)

Posted : 11/02/2020 8:50 pm
nuggetz
(@nuggetz)
Eminent Member
Topic starter answered:
RE: What's with the 95% flow rate?

@rat_patrol

Ok, that makes sense.  I just noticed that the start gcode in Prusa Slicer has a line that sets the flow rate to 95%. Why would that be in there? Probably why I always see 95% in the LCD menu when printing anything I sliced using the Mini profiles in the latest slicer. So, with M221 S95 ; set flow sitting at the bottom of the start gcode, will that override anything I set in the slicer? Not sure what its doing in there anyway. 

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Posted : 11/02/2020 9:16 pm
Rat_Patrol
(@rat_patrol)
Trusted Member
RE: What's with the 95% flow rate?

Flow rate is adjusted by the type of filament you are printing, as different filaments have different characteristics. For PLA, its usually 95%. For PETG for me is 98%, I run about 96% with ABS. 

If your extruder is calibrated (which it is on the Mini), you use the flow control to fine-tune your extrusion. You need to print some calibration pieces at different flow rates to dial it in perfectly. 

 

Posted : 11/02/2020 9:53 pm
JBinFL
(@jbinfl)
Reputable Member
RE: What's with the 95% flow rate?

perhaps this link will help.  I had similar questions a while ago and Josef himself posted on it long ago and far away.

https://forum.prusaprinters.org/forum/original-prusa-i3-mk3s-mk3-hardware-firmware-and-software-help/why-is-flow-set-to-95-as-standard/#post-122743

Strange women, laying in ponds, distributing swords, is hardly a basis for a system of governance!...
Posted : 12/02/2020 2:22 am
bobstro
(@bobstro)
Illustrious Member
RE: What's with the 95% flow rate?
Posted by: @joseph-b3

[...]  I just noticed that the start gcode in Prusa Slicer has a line that sets the flow rate to 95%. Why would that be in there? Probably why I always see 95% in the LCD menu when printing anything I sliced using the Mini profiles in the latest slicer. So, with M221 S95 ; set flow sitting at the bottom of the start gcode, will that override anything I set in the slicer? Not sure what its doing in there anyway. 

As @jbinfl notes, that specific line is in the startup gcode owing to a tendency of Slic3r (which PrusaSlicer is based on) to over-extrude. It's a bit of hack and causes a lot of confusion.

You can just create a printer profile and remove that line. One thing that may not be obvious is that if you make speed or flow adjustments, either using the front printer menu or gcodes, those values are retained between prints (as are others such as Linear Advance). I now make a point of resetting all of these values to 100% in my startup gcode at the start of each print to make sure everything is as expected at print time.

 

My notes and disclaimers on 3D printing and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan...
Posted : 12/02/2020 4:32 am
JBinFL liked
JBinFL
(@jbinfl)
Reputable Member
RE: What's with the 95% flow rate?

Bobstro:

Excellent info on the retained values and Prusa Slicer adjustment.  Thank you again!

Strange women, laying in ponds, distributing swords, is hardly a basis for a system of governance!...
Posted : 14/02/2020 12:16 am
Nigel Johnson
(@nigel-johnson)
Eminent Member
RE: What's with the 95% flow rate?

So whats the extrusion multiplier for?

If, (and a big 'if' I guess) you calibrate each filament, you set the e-steps, and then you work out the extrusion multiplier to get the exact width you are expecting. As long as this setting never changes then all good, but extrusion multiplier is for adjusting each filament, so why is there a printer level one as well?

Posted : 17/05/2020 9:17 am
AcE Krystal
(@ace-krystal)
Eminent Member
Does Extrusion Multiplier in Slicer actually do something?

What I don't understand yet though, is if the settings in slicer actually do something to the print?
If I change the extrusion multiplier in slicer from 100% to 90%, does this actually lower my extrusion amount even though the prusa "Flow" still shows 95? Is it now 90% of 95%?

I'm trying to solve sensitive to over extruding PETG.

Creative Engineer and 3D printing @ AcEcraft.eu...
Posted : 25/09/2021 10:40 pm
bobstro
(@bobstro)
Illustrious Member
They are independent but both are applied
Posted by: @ace-krystal

What I don't understand yet though, is if the settings in slicer actually do something to the print?

Yes. The gcode commands generated by the slicer vary the amount of filament extruded during a print move based on this setting.

If I change the extrusion multiplier in slicer from 100% to 90%, does this actually lower my extrusion amount even though the prusa "Flow" still shows 95? Is it now 90% of 95%?

Yes. They are both independent of each other, and neither has any awareness of the other. Think of a multiplier applied to a multiplier applied to a base value. The extrusion multiplier is applied at slice time, the M221 adjustment at print time.

I'm trying to solve sensitive to over extruding PETG.

I personally removed the Prusa M221 command for exactly this reason. It "hides" that adjustment outside of my slicer settings. I make a point of resetting M221 to 100% on every print in my start gcode and use my Extrusion multiplier setting in Filament Settings to tune for stringing and flow specific to one type of filament.

My notes and disclaimers on 3D printing and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan...
Posted : 25/09/2021 11:13 pm
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