Clearing a Jammed 3D-Printer Extruder

A scrapped Sovol hot end with blue filament still stuck to it.

There was a power outage while a print was running. The printer shut down, along with everything else. The Sovol then blinked back on, along with nearly everything else. I didn’t realize that the printer was still running, the extruder still hot, but the piece not moving at all, until it had been on for many minutes.

Cleaning filament from the extruder has been something of a nightmare, and it’s not done yet. Someone else had a go at it first. Despite some successes, measured by the fact that one of the cleaning tools could occasionally go in all the way, the print still wouldn’t work, and the extruder quickly got clogged again.

I decided to take a turn at it. I remembered a video I had seen where a couple of guys used heat to unclog the extruder, but I couldn’t remember any more about it. I retracted the filament, put some gloves on, and turned the heat up to 300 degrees, as hot as it would go. I then took up the tools — thin pieces of wire on thin handles — and started gently scraping away at the inside.

I occasionally worked a minuscule piece of plastic loose. This piece would inevitably be so small I couldn’t believe it was possible to clog anything, and slightly scorched, as if kept next to something too warm for too long. Eventually, the piece clogged up again and the wires couldn’t get through.

I have since learned that heating PLA to 300 degrees can possibly release toxic fumes. Yikes, good to know. Additionally the reason that the material was scorched might have been the extreme heat. So if you warm it to loosen anything up, don’t turn it up that high. Check your filament specs, and don’t go over the high end listed.

After patience, and literally hours, the wires could go in all the way, like they did earlier. I theorized that something up high melted in place during the power outage, and that the high heat worked it loose. Hooray, time to print now! But first a test.

I loaded the filament and… nothing came out. No print happened. Internet time.

The next step was a hard pull. I tried loading the filament, then unloading and yanking fast, to see if I could pull out whatever was stuck up top. Nope.

Meanwhile, a new extruder came in. It was installed, and the printer still didn’t work. The clog is way up in there. Joy.

The Bambu printer is working again (not my doing!), so that’s being used for now. It does feel more precise than the Sovol, although that’s a feeling, not a fact. The Sovol is bigger though, and I want that space! That means trying something else: taking apart the extruder and warming the piece that has filament stuck in it. I’m doing this one with help.

Well. Despite chipping away at it for hours, over the course of days, and taking turns at that, only partial success was had. A bunch of the area got cleared using the initial steps of warming and gentle dislodging, but the mess was too high up. That part of the printer was basically wrecked.

The next step would have been to disassemble the part of the printer that heats up and melts the filament. That part is called a ‘hot end’ and causes enough problems that fixing it has its own blog entry on the Sovol site. Boy that would have been a handy page to run across earlier: it would have saved me literally hours of research. Here is the page in case you have this same issue: How to Fix a 3D Printer Hotend Clog Step-by-Step.

We did not take it apart. This project had already eaten up around a week of free time, maybe a week and a half, and quite frankly nobody wanted to deal with it any more. We had succeeded in clearing the nozzle, and isolated the remaining problem to the hot end — good enough. We ordered another hot end and replaced the old one. It costs in the ballpark of $20 — ours was $21.79 and pretty nice in that it’s more versatile than the old one.