Estep Calibration issue (+-2mm extrude): Makerfarm i3v 12" w/3mm Hexagon .4 mm nozzle

[Freet128]

Hi Guys,

I have a Makerfarm i3v 12" with a Rambo controller board and hexagon hot end and when I run the 100mm extrusion test that was listed in the calibration video I get these massive changes in esteps that I can't figure out (more detail below). Also I noticed if I run the exact same extrusion test without changing the esteps in the LCD controller that I can get different amounts of filament consumed. The only thing I have changed from the stock kit was to use the Marlin 1.0.4 firmware, but I did modify it by comparing the Configuration.h and Configuration_adv.h files line by line. I couldn't just paste the old makerfarm files since they changed the endstop #defines.

My question is what could be leading to the different amounts of filament extrusion for the exact same estep settings? I have tried reducing the speed to 50mm/min in pronterface in case the steppers were missing steps but that didn't seem to change things.


Raw Data:
I only started suspecting the extrusion wasn't consistent after a few runs so I have a start from 917.5 esteps/mm:

917.5 esteps = 1.7mm short (at 100 mm/ min)
900 esteps = 1.94 mm short (at 50 mm/min)
917.8 esteps = 3.79mm long (at 50 mm/min)

I did a few more tests but I can't find the data, it was at 100 mm/min and one run was about 2mm short, and the exact same run was about 5mm short.

Any ideas?

[Carrot_or_Stick]

Try running a G92 E0 command to reset the extruder before you try to extrude the 100mm for the calibration test. The G92 E0 command resets the extruder.

[printbus]

It could be that 100mm/min is approaching the limit for how fast the hexagon hot end can soften 3mm filament. I reached that conclusion in the Estimating a Feed Rate Limit on Extruder E-steps Calibration post in the Marlin Motion Related Configuration.h settings for MakerFarm i3v thread. See if you get more consistent results running all the tests at 50mm/min.

Note that you can also run the test with a cold hot end. Remove the hot end nozzle so that the 3mm filament can pass through the hot end and start your test with an M302 command to enable cold extrusion.

[Freet128]

I cleaned out the hexagon nozzle, tightened the extruder tension screws, ran the G command between calibration runs and reduced the speed to 50 mm/min and that seemed to do it. Thanks!

It could be that 100mm/min is approaching the limit for how fast the hexagon hot end can soften 3mm filament. I reached that conclusion in the Estimating a Feed Rate Limit on Extruder E-steps Calibration post in the Marlin Motion Related Configuration.h settings for MakerFarm i3v thread. See if you get more consistent results running all the tests at 50mm/min.

Note that you can also run the test with a cold hot end. Remove the hot end nozzle so that the 3mm filament can pass through the hot end and start your test with an M302 command to enable cold extrusion.