Extruder calibration
Im at the midst of calibrating my extruder but the simple math behind correcting the e-steps isnt really working for me.
Either that, or my extruder likes extruding different lenghts randomly.
Lets take this baseline. At the moment my extrusion steps are 273,5.
With this, I extrude around 96 - 97 mm from the desired 100mm.
Now when I do the math (273,5 x 100)/97 = 281,96
And for a fact I know that this value cant be right, since I already overextrude with a stepper value of 280.
Heck I even overextrude with a value above 275.
And now Im running in circles.
Extruding, new math, new stepper value, either over or underextrusion.
But I cant get the 100mm right, not even close to 2%.
Am I doing the math wrong or something?
The values are just fluctuating way too harsh for me being able to hit the 100mm.
Re: Extruder calibration
How long are you taking to do that 100mm extrusion? Speed does need to be on the slow side.
Re: Extruder calibration
Have you tried to measure filament diameter?
The Bondtech extruders are pretty accurate with steps; cause of over-extrusion could well be filament diameter - even a very small increase in diameter will generate over-extrusion.
I tend to set all 1.75mm filaments as 1.8mm in the slicer; under-extrusion is less noticeable.
Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…
Re: Extruder calibration
About speed, Im using the standard speed in pronterface, something around 1,6 mm/s I think?
Takes around a minute to extrude 100mm.
I looked after the filament diameter, and of course its pretty perfect.
At highest its a difference of +- 0.01 mm.
What really stumps me is, that even after increasing the steps in 0.5 steps up to 175, the extrusion did not change at all.
How is that possible?
No matter if its E273 or E275, the first extrusion is overextrusion around 105mm and the following 3 are always 96 - 97mm.
I dont get it.
I definetly saved with M500 and checked with M503 if the values are saved in the eeprom.
Maybe its the bugged beta firmware. I think I´ll revert back to a stable one and try this out again.
This is extremly fishy, how can the extrusion vary on the first one so much and then not change at all if I change the steps....
Re: Extruder calibration
The other thing to look at is the tensioning springs. Back those off as far as possible while still being able to extrude at higher rates.
If the drive pulleys are biting in to the filament too much, it will affect your calibration.
Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…