Calibrating Extruder

Hey guys,

So I have a question on how to calibrate my extruder correctly. I drew a line on my filament 4" from the top of my filament inlet. In MC I told the extruder to extrude 100mm of filament. When it finished, I had 6.75mm of filament short of the 4" mark. 4" is 101.6mm, so that means I actually extruded ~94.85mm of filament.

I then decided I should try to get a more accurate measurement so I grabbed my caliper and actually marked 100mm on the filament feed. I was left with ~4mm, so I actually extruded ~96mm.

Is this even worth worrying about? I assume the easy way of 'calibrating' would be to adjust the filament diameter in MC until I extrude exactly 100mm? Is there a way to calibrate in the firmware somewhere?

Bonus question - What is the max effective speed of the R1? Looking for the fastest 'advertised' price of the printer without losing print quality. Looked all over the R3D website and couldn't find any info on it.

 

I pretty much used your same procedure and came up with an average 4% short over a number of trials. This is probably due to the groove in my hobbed bolt reducing its effective diameter. It's easy to change this in the Marlin firmware. In configuration.h just scale the 4th entry in DEFAULT_AXIS_STEPS_PER_UNIT. This is the change I made:

//#define DEFAULT_AXIS_STEPS_PER_UNIT {80,80,2267.72,723.38} // default steps per unit for RoBo 3D R1
// SLC - New Extruder value from calibration of 80mm filament extruder
#define DEFAULT_AXIS_STEPS_PER_UNIT {80,80,2267.72,753} // default steps per unit for RoBo 3D R1

753 is my new value. Now I have no idea if this small a change makes a difference. I suspect it is dwarfed by other issues like variation in filament diameter and filament composition. For example I found that Colorfab PLA/PHA tends to over extrude for me and I needed to modify the extruder multiplier.

 

I'm a bit confused, where does the original code end and your updated code start? Thanks for the help!

 

OK, sorry - the stuff after the "//" are commented out statements and are ignored. So you would edit this statement and replace the ***** with your new scaled extruder value.

#define DEFAULT_AXIS_STEPS_PER_UNIT {80,80,2267.72,*****} // default steps per unit for RoBo 3D R1​