Over the last six weeks (363 hours of printing) I came upon a problem where the filament would not extrude thru the nozzle. The extruder would pulse and then pop up with a CM2784 error.
On inspection it would appear that the top of the unicorn nozzle was not receiving enough heat to soften the filament within the nozzle. Therefore the extruder was pushing against a firm and solid filament that would not go anywhere.
Further inspection shows that the lower nozzle assembly would flex when changing a nozzle.
This was caused by the 2 screws (see picture) coming loose thereby not allowing the transference of heat from the nozzle upwards to soften the filament.
I tightened up the screws and all is well.
However given that the nozzle can be wiped about 5/6 times before each print it is well worth watching out for and checking weekly for these loose screws.
Just counted the number of passes of the nozzle over the spring wiper:-
Just @ temp 180 degrees 3 times
Just @ temp 170 degrees 3 times
Just @ temp 140 degrees 3 times
Just before actual print temp reached 230 degrees 3 times
12 times in total. Definitely something to think about.
I just needed to reach out and thank you for this post. I was having a nightmare trying to figure out why my K2 Plus stopped printing only after a couple of prints. I wasted about 6-8 hours of failed prints. I came across your post and gave it a try. To my amazement, my printer has worked flawlessly for the past 8 hours straight with such a simple correction. It was hard a bit tricky to get the allen wrench on the screw due to the rubber shield around the nozzle. I just can’t thank you enough for posting this fix and the clear instructions to show the screws that needed tightening. I don’t normally post in forums but had to in this case. Thank you so much!
I would urge others to check their nozzles. Especially those having Z height issues. You never know, so its worth a check just to eliminate the possibility.
