From one problem to another, huh? 150mm/sec is a pretty fast print speed. There's probably a few who can do that on highly tuned machines, but I think most of with i3v's don't go above 100mm/sec. I do most of my printing in the 75mm/sec range as a compromise in speed, noise, and print quality.Quote:
Originally Posted by UltraSaucy
What happens with the extruder gears when the extrusion stops? If the gears stop moving, focus on the motor. If the motor is getting hot it could be overheating and skipping steps. If the heatsink on the extruder's stepper motor driver is getting hot, the driver chip could be overheating; some add a small fan above the RAMPS board to keep the motor drivers cool. If the set screw on the small gear loosens or falls out, the small gear can start to slip - especially as the printer warms up. Do the gears rotate manually ok, without any catching caused by damaged or clogged gear teeth? If none of these possibilities pan out, maybe try swapping a couple of the motor driver boards around as a last resort.
If the gears keep moving when the extrusion stops, you're likely finding the hobbed bolt is chewing a notch into the filament. Nearly everyone seems to battle this at some point, and several things can cause it. Adjustment of the guidler bolts might help, but I don't recall ANYONE ever finding that was all they needed to do. Califdan just concluded his problem was the stock spool mount creating issues as the filament spool emptied. A few have found bits of metal clogging the hot end. Some have found the extruder nozzle needed to be cleaned/reamed with something like a guitar string. Too low of a print temperature can sometimes lead to stopping at random. Filament can have diameter variances that can catch on the top of the hot end. A few have used vegetable or grape seed oil as a lubricant in the hot end. Aggressive retraction settings combined with retractions that occur too frequently will cause the hobbed bolt to rotate back and forth in the same area of the filament, cutting away at it. The channels in the hobbed bolt can get plugged with filament, causing the hobbed bolt to become ineffective.
In my case, all I would have to do to recover is pull the filament out of the extruder, cut off the damaged part, and re-feed it. I'd then print fine again for minutes, or for hours. My issues seem to have been overzealous retraction settings and a spool of filament with bumps in it just large enough to not pass into the hex hot end.
You can look at printer moves in a gcode viewer to see how often retractions are occurring. Sometimes the tail end of prints can be a problem since the print area often gets smaller and smaller, and retractions are occurring with less and less extrusion in between them. For my 1.75mm filament, I usually configure Cura for 1.2mm retraction distance and a minimum extrusion between retractions of 0.5mm; both settings are significantly different than the Cura defaults that are optimized for the Ultimaker printer. On long prints that don't have a complex perimeter structure, I disable retraction as a final precaution.
