PrinterJournal / Bowden Tube Flush with Nozzle
My 3D printer was in a state where it seemed to need the nozzle unclogged after each print. The issue was that the PTFE tube was not flush with the nozzle, due to the hot end coupler being “worn in” and feeling like it was fully extended.
Today I am detailing a clog in the Bowden tube, specifically the space at the end. The resolution was to check that the PTFE plastic of the Bowden tube was extending past the heat brake and touching the nozzle once assembled.
When I was reassembling the hot end (after cleaning) I checked and found that the Bowden tube could not be pushed any further. I had assumed that this meant the PTFE material was flush with the nozzle. Following this my printer would go through a print alright, but, then clog badly enough that the filament would have a groove sanded in it. The extruder would skip for a while before this, but, then stop because there was a big enough groover worn in the PLA that it couldn’t push it anymore.
It seems that the hot end coupler had worn a ring into the PTFE tube and was gripping that, making it too hard to push the PTFE tube flush with the nozzle Without being flush, there was space for the filament to expand and cool between the nozzle and the PTFE tube. Once this happened, the Bowden tube was blocked and while the motor could still push it would eventually grind away the PLA and stop skipping.
Once I understood the problem, the resolution was simple; I pushed the hot end side coupler up the PTFE tube and checked that the other end was extending past the heat brake. This check is something to do when. You should check to be sure that the tube would extend past the heat brake, and possibly shave down the POTFE material a bit. The nozzle doesn’t go 100% into the heating block, that’s fine as the rest now is snug. with this done, I’ve been able to resume printing - I had unrelated adhesion problems so had to restart, however, it means that I know it’s not going to jam after one print
