Nozzle Clog -- Help!

General LulzBot Mini
1

So, I’ve had my mini for a little over a year now, and it has been a constant source of joy in our household. A couple weeks ago, though, the nozzle clogged up in the middle of a print, and I am out of ideas on how to fix it.

I read the official page about unclogging hot ends, but it seems to assume that I can get filament down into the melted part and use that to pull some out. So far, I haven’t been able to. It broke off flush with the top when the nozzle clogged and while I’ve been able to get some of the filament out between tweezers and a drill, I can’t get the filament down low enough to where it would merge with what’s melted.

I tried melting the filament on the side of the hot end and sticking it down the hole, hoping it would grab onto something – no dice. It gets stuck, but not well enough to pull anything up.

I tried sticking a safety pin up the nozzle, both hot and cold. It can’t get very far, and doesn’t seem to let anything through.

I’d cheerfully clean out the nozzle with a screwdriver or something if I could get it off, but the instructions for getting it off and back on are a little intimidating, and I’m sure it’s even worse if the thing is full of hot plastic.

I thought – well – I’ll just replace the whole tool head. Those instructions don’t look too bad . . . and it turns out the store’s out of the one I would need!

I’m not sure how it got stuck. I’ve only ever used filament from the Lulzbot store with this – occasionally HIPS, occasionally PLA. I had just finished a print with some blue PLA and switched over to the red HIPS. It got about an hour into the print before clogging up. For a while, I could get to extrude the tiniest little pig tails by pushing really, really hard on the top. Now I can’t get it to do even that anymore.

Does anyone have any last ditch methods for unclogging a nozzle? I really miss my printer. :frowning:

2

We decided to take the tool head apart to get better access to the nozzle to remove the plastic. That worked pretty well, but we broke a fragile wire in the process and the whole thing is beyond our ability to repair now. Ah well.

3

Well the other way to clear a clog would be to soak the nozzle in a solvent which can dissolve the filament.
ABS - Acetone
PLA - SCIGRIP 4
HIPS - Limonene

Try 30-32AWG solid wire is .25 and .20mm, should be able to get into the nozzle opening completely… nichrome or magnet wire is usually my best bet to finding a solid wire in this small a gauge. A safety pin is probably the next best thing, but could enlarge the nozzle.

The small wire which was broken is probably the thermister… you can buy spares from http://itworks3d.com/product/thermistor-3d-printer/

Hope that helps.

4

If you haven’t already looked, I-T-Works (https://itworks3d.com/) may have spare new or refurbished tool heads. I bought one for the school where I’m helping out. They carbonized some PLA in the hot end on one of their first prints. A couple of the 5 & 6 grade kids did the tool head replacement following the instructions on the Lulzbot web site with just minimal oversight from me.

We do also have a few spare parts for the tool head we keep around just in case. I figured having the whole spare head on hand wouldn’t hurt to maximize their up-time (of course, as soon as I bought it, we’ve had no more troubles).

5

Also bead wire works, or at least it does for me.

6

On the nose! It’s like you’ve done this before. Thank you so much for the link – I hadn’t realized there was somewhere else I could go for spare parts, and was really, really missing my printer.

7

Email Jamie at info@itworks3d.com. He runs the place. If there’s a part you need or can’t identify, he’s always been extremely helpful finding it!

8

Up and running again. Thanks so much!