I had a really bad two days with my Creality Ender 3 where the print would start OK but would after a while (say 10-30 minutes) the nozzle kept clogging so the filament would stop feeding. The drive wheel would be doing its best and trying (but failing) to feed the filament. The nozzle was blocked. So nothing would be coming out.
Here’s a typical fouled up print:
Worse still, when I tried to figure out why, and reheated the filament to get it out of the nozzle I managed to pull out nightmare contortions like these. These were all variously stuck in the hot end and I only managed to get them out by reheating the hot end on each occasion, removing the PTFE tube and pulling (hard!).
Nozzle Cleaning Did Not Help.
I variously tried cleaning the nozzle, then changing the nozzle. All to no effect. Incorrectly I began to suspect that there was something amiss with the filament I was using. In desperation changed both the bed temperature and the nozzle. At the higher nozzle temperature the thing at least got to the end of the print, though the output was ugly and obviously too hot.
I was at my wits end. Then I Googled it and came up first with this video from Creality, which largely answered my query. But the second video is even better.
Here’s the Creality video on Nozzle Clogging first:
If you remove the nozzle you should be able to push the PTFE tube right through the hot end. I began to get suspicious, so I wondered, when the nozzle is actually thee, how far into the hot end should the PTFE tube go?
The Definitive Video on Nozzle Clogging in a Creality Ender 3
Then I came across this magnificent video (below) by a guy called Nerys who made a large print head model to show what the problem was. (Both videos are worth a watch but this guy’s video is awesome).
The end of my PTFE tube was worn and so it mated poorly with the back face on the print head (I have a suspicion it was even worse than this! I simply had not pushed the PTFE tube in far enough!).
One thing in particular that Nerys flags up is that the top entry grommet for the PTFE into the print head should NOT be fully tightened down until the PTFE tube has been installed. The last turn/half turn will tighten the PTFE tube snugly down onto the face of the nozzle.
After all that grief and suffering, I carefully cut a centimeter off the end of the PTFE tube (make sure it is a right-angle!). Then I fFitted it back as described by the Guy in the video. I tried again with saner temperature settings. I sighed with relief when it printed perfectly.