Hi, If I could pick your brains for a moment,

Hi, If I could pick your brains for a moment, I 'm having trouble printing on my latest printer… (ingentis / Eustathios / rigidbot). On the photo, i’ve done a torture test. On the left, my old trusty Prusa I2 /w direct drive filament. On the right, my clone using bowden and airtripper’s extruder. both have the same setting to print out. 80mm/s with 205C temp. they both have a J-head (the prusa has a brass ending while the clone has a aluminium one). both tests were made witht the same spool… Has you can see, the clonde is having trouble printing.

Its got a Nema17 step motor with a MK8 gear. its set to 149 in the firmware with a 1/16 step. I dont feel # hear the stepper skipping so I dont think thats the problem…

Anyone have a suggestion ? I’m all out of ideas on this one.

Thank !

Change the j head and print with the clone.

Yeah, the problem is that I can’t install the push to connect on the J-head thats on the prusa. I cant screw it on. I would have to tap the head… i’m not sure thats a good idea

Could be a temperature issue. The one on the right looks too cold to me. Maybe try cranking it up 20 degrees or so. Maybe your thermistors aren’t calibrated equally. I know on the e3d v6, you have to make sure the thermistor is secured all the way inside the heater block or it will read low, especially when the fan kicks on.

Back to basics question:
It appears you’re under-extruding; have you calibrated your extruder steps/mm?

@Jason_Smith I did one @ 215C and it looks a bit less messy but still has some problems on the layers. I have #1 as the thermistor in Marlin… maybe #5 would be more appropriate.

@Carlton_Dodd Yes I did… used a piece of filament, marked it at 50mm,100mm,150mm and 200mm and calibrated the firmware until I could move between those marks and been on the dot every time.

@Jean-Francois_Coutur Well, darn. That’s the extent of my thoughts.

It definitely looks like either it is under-extruding, or the temperature is too low (assuming the filament is not simply getting chewed up and skipping on the hobbed bolt/gear).

If under-extruding, it could be the stepper skipping or a calibration problem. Since you’ve nailed the extrusion length, skipping steppers might be the problem. Are they getting too hot? Or perhaps the driver chips are getting hot? Do you have heat sinks of the driver chips?

If the extruder stepper motor or the driver chip are both not too hot, then Occam’s razor likely applies and it is probably the temperature.

If extrusion temp is low (what it looks like), then maybe try going up 5 deg C increments and re-print; repeat a few times, but 20 degrees is probably too wide a range since it is already melting.

Or, could it be the filament has absorbed water?

Here’s a reference: http://reprap.org/wiki/Print_Troubleshooting_Pictorial_Guide

@SirGeekALot I tried 200C, 205C, 210C, 215C, and now 220C, all the same…

Driver overheat could be a cause, theres a heatsink on the DRV8825 (should not be but there is…) I can keep my finger on it but it is hot to the touch. I just dialed down the pot a bit while is was printing… it was getting less and less warm. I’ll have to restart tomorrow 'cause its bed time over here ! :slight_smile:

Dont think its a humidity problem. Like I said, both print were done one after the other… just changement the spool from one printer to the other.

Maybe I do have under feeding… but, that would trough all my calibrations out the door… sigh

Check the actual nozzle size. I am sure you are under-extruding, if your calibrations are correct, than it must be a setting. I am betting the actual nozzle size is larger than what it is marked. This would cause an otherwise properly calibrated printer to under-extrude.

Also check the filament diameter in several places and around in each place. This looks like maybe the filament size is smaller than programmed in the software.

Better to use geared extruder. Bowden adds load to stepper. So your diver/motor is hot.

@Jason_Barnett I was not aware of that ! thanks for sharing, i’ll check and see… maybe also ramp up the step/mm in the firmware.

@D_Rob Did that, I was pretty mush around ~ 1.75mm

@karabas3 So true. I have that on my prusa i2 and its working great… I did try Richrap’s version for the bowden tube… just not on the latest machine. maybe i’ll look into it. :slight_smile:

@Jean-Francois_Coutur were you using calipers? calipers are not an optional piece of equipment in this process. accurate measurements need to be taken on every roll of filament. try subtracting .03mm from filament diameter. also try a different slicer. cura if you are using slic3r or kiss, and one of the others if using cura

@Jean-Francois_Coutur In extrusion, “pretty mush (sic) around ~1.75mm” is not close enough.
Remember that 1.7mm diameter (2.270 mm^2 cross-section) is 5.7% less plastic than 1.75mm diameter (2.405 mm^2 cross-section). This is why inconsistent diameter filament sucks to work with.

@Jean-Francois_Coutur I did a quick comparison sheet: https://docs.google.com/spreadsheets/d/1tuS-unlm1qB_Qm2DWabqFXfo6vXe12kYtgU8JagA4tw/edit?usp=sharing