I’m certain someone else has solved this. Notice a pattern or trend in my prints?
PLA, 190, 200, and 205 degrees, varying brands of PLA, Varying speeds and feeds. I’m thinking it’s something to do with either the tension on the hobbed bolt, or a restriction that’s causing the filament to strip on the hobbed bolt, causing it to grind a notch.
Incidently, prior to the print failing, I have the sucker FLYING, 153% of 20 mm/s, and it’s extruding and filling and cruising just fine.
It may or not may be it, but your steps per mm on extruding may be low. I had an issue were I didn’t microstep for more torque. But as I printed faster I was getting weird texture and poor bonding. I turned up microstepping to were I have about 300steps per mm which fixed my problem.
I have the Rumba set to 32 microsteps per step, and the firmware set to 800 e-steps per unit…which seemed a lot higher than the default for the Marlin firmware, 270 at 8 steps per…but a little math says it oughta be 1080…which is wierd, because it’s otherwise extruding adequate amounts (sometimes waaay too much)
Yeah. I flashed 1080 and it’s producing 15 mm of travel for 10mm of requested filament.
Perhaps your are too far in the other direction and not getting good torque and missing steps.between 250 and 350 is probably best. I always fine tune at the by extruding exactly 20 mm and measuring the filament and re-adjusting as well as using the exact filament diameter in slic3r measured with calipers.
Yeah, I dunno, it seems like a long steady-state problem…each of the prints fail about 45 minutes in (I should pay attention next time)
I’ve had plenty of <30 minute prints that are turning out fine.
@Mike_Miller did you check your filament driver after or around your 45 min mark ? On my old reprap, the parts (pla) would get soft after around that time and the extrudet gears would slip and cause similar issues. Might be worth checking out…
30mm/s is flying?
@Tim_Elmore compared to zero? 
@Mark_Moissette_ckaos I’ll throw a fan on the Bowden and retest
@Mike_Miller , two things cause this issue with PLA prints that fail repeatedly after a set time. The first is your hotend barrel not getting enough active cooling, like a 40mm fan blowing across the peek section. This is the dreaded PLA plug! Cooling fan on the barrel is a must for most if not every hotend. The 2nd issue that can cause this fail pattern is, if your extruder motor gets hot enough and transfers the heat to the Hobbes drive roller, it can soften the PLA and cause it to strip out easier, leading to loss of extrusion. I bet one of those two fixes you up real good
The Skull is almost complete. I’ve got a fan blowing on the motor, and I’m ‘helping’ the filament (feeling movement and applying pressure.) to get this first print complete.
If that works out, I’ll Keep the fan on, turn down the driver a little, and see if it’ll print the Zombie Hunter without my help.
It make sence, it always seemed to print better the morning…when everything’s cold.
So, Skull worked while I babysitted it, Zombie hunter didn’t, being left entirely to it’s won devices.
Im beginning to think under extrusion is causing the PLA to heat up and clog as a couple of the failures have the bowden mooshing the filament up just after the pinch wheel.
It’s an e3d head, the fan is on, the temps are about 205, the extruder motor is actively cooled, and just before it fails, you can see the extrusion rate fall off.
That’s total sign of the Pla plug in the hotend. Is the fan on the barrel on full blast, and as low as possible on the fins?
Pretty sure, but I’ll look closer (and, sigh, wire it to constant on.
