Range for extrusion multiplier and stuff

First let me say I'm just getting started at this so please be kind if I ask some dumb questions.

In regards to the "Extrusion multiplier" I have been using a 3mm extruder with good results having calibrated the extruder by modifying the config file of the Marlin firmware until the length of input filament extruded is what is specified by the user variable in proterface. I extrude 100mm of filament and exactly 100mm goes in. Then I measured the filament diameter and entered that into Slic3r, slice up my parts and the thing worked pretty well.

I'm doing some finer work so decided to switch to 1.75 mm filement and a new extruder. I did the same calibration as I did with the 3mm filament, and entered the measured value of 1.74mm into slic3r, but when I started printing parts way too much plastic was being extruded. I had to set the Extrusion multiplier down to 0.5 before the parts started working and looking good. What am I doing wrong?

Also, is there a reference that describes what each of the parameters in Slic3r do? Most of them are obvious, but others I'm not sure about, specifically "First layer height ratio" and the effect of the "Nozzle diameter". Also "Extrusion width" in Advanced.

Thanks,
Ken

Ken,

>Also, is there a reference that describes what each of the parameters in Slic3r do? Most of them are obvious, but others I'm >not sure about, specifically "First layer height ratio" and the effect of the "Nozzle diameter". Also "Extrusion width" in >Advanced.


I found Slic3r is nicer link a great starting point.

Mike

Wow, great link, thanks!
But it makes me even more confused as to why my Extrusion multiplier must be set so small, it should be 1, but that puts out like WAY too much plastic...
Ken

Are you sure your extruder steps per are correct?
Slic3r expects it to me in mm of input filament.

kburgess Wrote:
-------------------------------------------------------
>... Marlin firmware ...

> I'm doing some finer work so decided to switch to
> 1.75 mm filement and a new extruder. I did the
> same calibration as I did with the 3mm filament,
> and entered the measured value of 1.74mm into
> slic3r, but when I started printing parts way too
> much plastic was being extruded. I had to set the
> Extrusion multiplier down to 0.5 before the parts
> started working and looking good. What am I doing
> wrong?

Do you have EEPROM_SETTINGS enabled? If you do, Marlin will only use the settings saved in the eeprom. You need to send a M502 to use the new firmware settings. Then send a M500 to save the new firmware settings.

Embarrased to say that my original calibration was incorrect, it was actually extruding 200mm instead of 100mm, not sure what happend but when I re-measured I discovered the error. No wonder 0.5 worked, but I'm sure I'll get better parts with the correct calibration. Thanks to everyone that spent any cycles on my question
Ken

Something very odd is happening with my extruder.

When I set Pronterface to extrude 100mm at 100mm/min the extruder runs for one minute and extrudes 100mm of input. But if i set Pronterface to extrude 100mm at 50mm/min my machine (Marlin based firmware) only extrudes 50mm? What's up with that? Is there some kind of timeout for a single extrusion command in Marlin? I don't see any configuration parameters that I think might have to do with this?

When I try to make parts my extruder is putting out too much plastic, but the "failure" above always seems to fail with too little plastic extruded. I think my extruder is calibrated, it puts out 100mm at 100mm/min when Pronterface is set to extrude 100mm, and 50mm at 100mm/min when set to 50, but only 50 when set to 100 at 50mm/min, and 25 when set to 100 at 25mm/min so I'm still not to sure about it...

Ken

I did find this in the configuration file

#define EXTRUDE_MAXLENGTH (X_MAX_LENGTH+Y_MAX_LENGTH) //prevent extrusion of very large distances.

But my X_MAX_LENGTH and Y_MAX_LENGTH are both greater that 100
however these constants are are defined later in the file that the line above, is that OK?

I also see the line
#define DEFAULT_MAX_FEEDRATE {500, 500, 5, 45} // (mm/sec)

but I'm not close to 45 mm/sec the feedrate that "works" is 100mm/min (0.6mm/sec) or even 200mm/min whereas it appears that 50mm/min and 25mm/min fails to extrude 100mm ...

Ken

Yes it is OK that the lengths are defined afterwards as long as they are defined when EXTRUDE_MAXLENGTH is used.

I can't see why it would compare the extruder input length with the travel distances since it typically comes out much longer than it goes in.

What happens if you type the G code directly? E.g.

M83 ; use relative distances for extrusion
G1E100F50

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[www.hydraraptor.blogspot.com]

Hi! here is a guide to calibrate en "extrusion multiplier"

Hope this works