Page 1 of 1

Total Filament Used

Posted: Thu Mar 03, 2016 5:25 pm
by Johncoffee
I just observed that the total filament usage appears rather high on my Rostock Max V2: Every 1+1/4=5/4 rotations of the white tooth wheel, the usage increases 0.1m
As the diameter of the inner filament drive shaft is approx. 12-14mm (just guessing now), I would calculate the feed to just about half: 0.05m

(Or the other way around: 0.1m * 4/5 / Pi = 25.4mm Diameter of the filament drive shaft which can't be correct)

There seems to be any error in this calculation.

Anybody observed the same?

~

Posted: Fri Mar 04, 2016 3:26 am
by TheIrishScion
I haven't invested as much time in the question, but I was quite surprised at my indicated filament usage (~70m in ~11 hours of printing, alas my RAMBO just got shipped back to SeeMeCNC for diagnosis or I'd look up exact figures.

It's plausible alright, but it felt a little high. I should go measure my hobbed wheel and check when I get my board back.

If you wan to definitively check the theory, pop your bowden tube off and free the filament. Then advance filament from the computer until you crest a .1m boundary, cut the filament off and advance till you crest another 1m boundary and measure. See how far out the system is.

Re: Total Filament Used

Posted: Fri Mar 04, 2016 6:00 am
by Johncoffee
Thanks for your reply TheIrishScion. I will measure it before the filament enters the hobbed wheel - but I'm almost sure that the value indicated will be too high...

Re: Total Filament Used

Posted: Fri Mar 04, 2016 12:50 pm
by Polygonhell
There was another thread on this, and it does seem high.
I did actually look at the source code and the logic seems reasonable.
It's just recording the steps sent to the extruder and multiplying through, the only odd piece of logic is when that data is committed to EEPROM, it's possible if the printer is reset mid print, no filament usage is recorded.

Re: Total Filament Used

Posted: Fri Mar 04, 2016 6:10 pm
by TheIrishScion
Polygonhell wrote:There was another thread on this, and it does seem high.
I did actually look at the source code and the logic seems reasonable.
It's just recording the steps sent to the extruder and multiplying through, the only odd piece of logic is when that data is committed to EEPROM, it's possible if the printer is reset mid print, no filament usage is recorded.
Right, I can see an unexpected shutdown could lead to under-recording, I don't know how often the system bothers committing to EEPROM, but the logic for filament counting should be _super_ simple.

I'm await your results with interest John.

Re: Total Filament Used

Posted: Fri Mar 04, 2016 6:18 pm
by TheIrishScion
I imagine this is the thread you were talking about?
http://forum.seemecnc.com/viewtopic.php ... 17&p=52340