How to tell when the PTFE coupler is bad

[the_schire 3]

So I've had my UMO for a few years now, and it's been having an increasingly difficult time pushing material. Last time I tried to print something, I couldn't really push any material through and have spent the last week trying to clean the nozzle and figure out what the problem is. I have never replaced the PTFE coupler, and I'm wondering if that is the problem, causing restrictions and also contributing to the under extrusion I was experiencing when I could still move material.

[droopas 0]

This sound much like the problem I had recently. After a completed print the filament would get stuck and I had to take out the PFA tube and cut off the end of the filament to a taper and reinsert the tube back.

After a while it got tiring, so I replaced the PTFE coupler. It fixed the problem. Cutting open the old PTFE coupler revealed that it had formed a cavity which allowed the filament to expand, and thus get stuck in the PFA tube.

[Dim3nsioneer 440]

Do you have a picture of that cavity by accident? That would be very interesting to see.

[the_schire 3]

Update, turns out it was the nozzle. Some how it got so clogged that I couldn't even blast out the gunked up material with a torch. Soo... I grabbed the smallest drill bit I have and made myself a 1mm nozzle. Prints faster than ever now