I have an all-metal V6 hotend clone that has worked in the past, but recently will clog very easily.
I've tried the following to address it:
- Clean/replace the nozzle (0.4 or 0.5 mm, nozzle is hot-tightened)
- Ensure nozzle is tightened against the heat-break tube, not the heater block
- Adjust nozzle temperature higher/lower (190 °C to 230°C)
- Recalibrate extruder steps/mm
- Improve cold-end cooling with a 40mm fan (also, a 40 mm blower directly aimed at the fins did not help)
- Try different filaments, from different brands (all 1.75 mm PLA)
- Adjust slicer settings (speed, line width, layer thickness is usually ~0.2 mm) and even tried different slicers
- Reduce/eliminate retractions
- Replaced stock Ender 5 Bowden extruder with dual-gear setup for higher grip
- Replaced the thermistor (wire was getting worn from disassembling/reassembling)
Some things I've noticed:
- Prints tend to work fine for a while (~30 min to 1 hour or so), then the extruder is suddenly unable to push filament through the Bowden tube and begins to grind/click. There is very little to no period of reduced flow. It simply stops flowing completely.
- I am unable to push the filament through by hand to clear the clog, but pulling the filament out and trimming the end works
- The very end of the filament is the only place with any signs of being molten, well within the nozzle length itself
- Pushing and pulling the filament in the hot-end by hand works for very small retractions, but can instantly result in a clog if pulled too far back (a few mm)
- So far I have not seen particles / black buildup / other gunk that would explain the clogs
- Letting the filament sit in the hot-end for a few seconds is enough to make it much harder to extrude by hand until enough filament is pushed through to clear what's melted (sitting too long will make it clog), but there are still no signs of heat-creep beyond the nozzle length.
- I can always easily pull the filament out by hand after it jams (while still hot)
Examples of what the filament end looked like when a clog formed:
Since the melted material is so short I don't think it's heat-creep. Maybe it's the (very cheap) nozzles themselves having inconsistent dimensions? Not being able to retract a few mm and re-extrude by hand seems pretty odd. I have ordered official E3D nozzles to try in case they are the culprit.
Any thoughts on what else it could be?
Edit: I had commented with the new nozzle being a solution, but unfortunately I spoke too soon. Using the E3D nozzle helped for prints that maintain a high enough flow-rate, but when printing small parts and/or multiple parts it seems that the flow rate becomes low enough to overheat the filament and clog (even with reduced print temp to 190 °C).
Update: While using the new nozzle and improving cold-end cooling with a blower aimed directly at the cold-end fins did help delay the clogging a little, it did not prevent it. It seems unrealistic to say that this is traditional heat-creep since the fins were cold to the touch and the length of deformed, clogged filament is even shorter than before (<5 mm).