Did I just break my hot end?

[TimMcBrayer]

I've been printing PLA with my Rostock Max V2+. (The 2+ is because it came with an EZRStruder. Otherwise, it's as documented in the assembly instructions.) The printer has been operational for around a month. This morning, it stopped extruding. This evening I diagnosed it down to the hot end being jammed. I couldn't pull the filament in or out, with the hot end at 200C. So with the printer cold, I cut the filament at the EZRStruder, removed the tip, and pulled the tip + filament out.

The filament was well and truly embedded in the tip. I pulled on the free filament enough that it snapped and the mini-bowden tube attached to the hot end came off. The filament was wedged tightly into the tube and could *not* go backwards. I was able to push it forwards and out of the tube. Now, the hot end tip looks like this.

My hot end nozzle.

I've now only got a couple mm of PLA to grab on to. But it wouldn't matter because (at least cold) the filament will not budge. The exposed filament is mushroomed enough that the tube will not fit back into the brass tip.

Where do I go from here? Invert it in my oven, bake the tip to 250C, and hope the PLA will run out? Give up and buy a new tip, since it's only a $9 part? Something else?

[mhackney]

A soldering iron or small butane torch to gently heat the nozzle starting at the tip. Hold the nozzle tightly in vice grips. Grab the nub with needlenose pliers and start to pull. As the PLA warms it will start flowing and your pulling will start to extract it. If that fails or of not all comes out get a wire or needle that will fit through the nozzle. Heat the needle and and push it through the nozzle. Keep picking away through the nozzle and at the back end while heating the nozzle. It is 100% fixable.

[Eaglezsoar]

I invested in the tiny metric drill bit set that includes 0.4mm and .5mm bits, link is here:
https://www.amazon.com/Awakingdemi-150- ... +drill+bit

[geneb]

My trick is to stick it on the sidewalk outside and hit the little sucker with a propane torch. Plastic comes boiling out both ends after a bit and it's clean as a whistle.

Make sure filament can still pass through the PTFE liner without problems - when the liner gets over heated, it can shrink a little bit and cause problems.

g.

[TimMcBrayer]

Thanks for all the advice, helping a newbie out with basic information like this. I'll try a 30W soldering iron, a 110W soldering gun if that can't do it, and last effort the propane torch (a.k.a. 'nuclear option').

The PTFE tube got pulled out because the filament had mushroomed inside it. That end of the filament is visibly bigger than it should be. So, I think once I get the nozzle cleared I should be good to go.

[mhackney]

The little butane torches work great for this too. Gene likes to go large on things, I take the more moderate path.

However you do it, you do want to avoid charing the PLA as much as possible. That's a $%^& to get out. The little bits Eagle linked to are perfect and everyone that 3D prints should have a set.

Another trick is to take a 6" piece of PLA and heat up the end and then smoosh that into the sort piece on the back to make a handle. Let it cool completely before tugging on it though.

[TimMcBrayer]

With my 30W iron, the filament stretched and snapped, as gentle as I tried to be with it. So, I went big with the propane torch, because that's what I have. I'm sure I overdid it (it was night and the tip got to glow red slightly...), but the end result is that the nozzle is clean and running ABS quite nicely right now.

I'm sure you all realize this, but if you don't recalibrate after removing/replacing the tip, your next print won't come out very well. I learned this directly. The print wouldn't stick due to Z=0 being too high. I re-set the Z height, went through the full recalibration because why not, and the post-calibration print is coming out beautifully.

[Eaglezsoar]

Congratulations on getting it up and running again!

[mhackney]

Great. One thing to be careful of - getting brass to red hot anneals it and it becomes much softer. Unlike steel, it can not be hardened by heat treating (you work harden brass). So be careful not to jam the nozzle into the build plate, etc. I don't expect you to have any problems but just wanted to point that out. Try to minimize how long it is red hot and avoid it if possible.

[TimMcBrayer]

The printer is working well, and I have ordered spare nozzles as well to have both a backup and also the finer 0.35mm size. I realized I held the torch on too long when I saw the slight glow, and stopped immediately. I do appreciate the warning, and will be on the lookout for any issues with softening of the nozzle.

Once again thanks for all the advice and guidance!

[mhackney]

Also meant to add about a soft nozzle - abrasive filaments like carbon fiber filled will destroy it quickly!