Help stop heat creep
Hi guys - I have been successfully printing the same model on my MK3s for many many years (I think almost 4) . Same Overture PLA filament (bed 60-65 nozzle 215-220) and model which also prints perfectly on my other (3) MK3s printers. Now I think I’m suffering from heat creep on one of them. I’ve disassembled, inspected and cleaned my hotend and extruder assembly multiple times and insured proper thermal paste on the heat break and the ptfe tube is clear - the extruder motor seems to work and the heatsink fan RPM is in the optimal range. I checked the tension spring and gears and set screw on the motor shaft and nozzle. However my prints are still failing with under extrusion, filament bits on the bed and eventually the filament stops extruding and I walk in only to see the printer printing in the air - I try to unload the filament and you can hear the stepper motor but there isn’t any gear movement - the filament is stuck. Through testing - as it started to print with no issue I eventually hear some clicking, adjusted the idler tension and it stopped and continued as normal. Then 30 min later it stops extruding. Everything hardware wise - gears, housing heating elements and thermistors seem fine and no errors are reported. I have successfully printed multiple 3x3 calibration mesh squares through my testing after reassembly- only to find each time my longer 5hr prints are failing. (More retractions - but it usually fails on the first layer) - yesterday after 1 more attempt my 5hr print showed signs of the problem - but made it much longer than before. I ordered a bunch of replacement parts including new hotend element thermistor and stepper motor as a backup - as I’m not sure what else it could be. I love this printer just not sure what I may missing.
thabks
thanks
UPDATE - it was my extruder motor
After 7000 hrs of printing - and all the testing I did - I replaced the extruder stepper motor and so far I am getting perfect prints once again. All the symptoms and forum posts and google searches all pointed at heat creep. A great way to trouble shoot this - remove the motor and twist it by hand - it should spin freely. Mine felt very tight like it was seizing. The red herring for me was that when I attempted to fix the extruder hotend assembly - it always printed fine during the 3x3 calibration mesh model - which had little to no retractions - it was when the retractions started with larger prints that eventually the motor would fail and then obviously clog the nozzle and heat-break. Hope this information helps.