[SOLVED] Underextrusion at 0.1mm but not at 0.2mm layer height
-
@deckingman said in Underextrusion at 0.1mm but not at 0.2mm layer height:
@phaedrux said in Underextrusion at 0.1mm but not at 0.2mm layer height:
..............................
You can combat this a little bit by setting the extruder to a higher microstepping. I find anything over 64 causes hiccups. .........................Just a "for info". The extruder moves much faster when doing retract/unretract than it does during normal print moves and that's what causes the hiccups. So if you are able to retract at slower speed, then you can push the micro stepping up a bit further. The step pulse frequency limit is about 200,000 so if you take the steps per mm, multiply that by the micro-stepping then divide the result into 200,000 it'll give you maximum extruder speed that you can use.
HTHSo with 850 steps/mm at 16x that would mean 14,7mm/s?
-
@obeliks said in Underextrusion at 0.1mm but not at 0.2mm layer height:
@deckingman said in Underextrusion at 0.1mm but not at 0.2mm layer height:
@phaedrux said in Underextrusion at 0.1mm but not at 0.2mm layer height:
..............................
You can combat this a little bit by setting the extruder to a higher microstepping. I find anything over 64 causes hiccups. .........................Just a "for info". The extruder moves much faster when doing retract/unretract than it does during normal print moves and that's what causes the hiccups. So if you are able to retract at slower speed, then you can push the micro stepping up a bit further. The step pulse frequency limit is about 200,000 so if you take the steps per mm, multiply that by the micro-stepping then divide the result into 200,000 it'll give you maximum extruder speed that you can use.
HTHSo with 850 steps/mm at 16x that would mean 14,7mm/s?
No, sorry I didn't make that clear. I should have said, if you have the steps per mm at 16x, then first divide by 16 to get whole steps then multiple by the new steps per mm. If you have already got the steps per mm at the desired micro-stepping, you simply divide that into 200,000. So with 830 steps per mm, you can go up to 241 mm/sec. You'd need to go to 256x micro-stepping to get as low as 15. Sorry.
-
OK, that makes more sense.
-
Or use my Extruder Microstep Calculator. Just enter steps/mm (@ x16) and look at the
Max Retraction Speed (mm/min)column of the result table that will give you these values for all available microsteppings.
For this case you can simply ignore all other input fields and result columns.
Manuel
Duet 3 6HC (v0.6) with RPi 4B on a custom Cartesian
with probably always latest firmware/DWC (incl. betas or self-compiled)
My Tool Collection -
@wilriker I'd forgotten that you'd done that.
-
Back to the original topic. I finally found some time to play with the printer again and tried your suggestions.
I have forced the steps per mm to 64 and did a test print. It did not fix the problem but the extruder motor was louder.
I have printed 2 hollow test-cubes next to each other. There were no signs of under extrusion but the retraction cylinders looked bad.
Finally I have decided to just use the extra prime amount for the time being. It gives me the good results inspite of my reluctance to use it.
Thank you for your input. I learned a lot about the finer details of extruders.
