My Dremel 3D45 Keeps Clogging!

On your 3D printer, some parts are “consumables”, meaning they may need to be replaced during the useful life of your printer. But what are they? Have you ever considered that the all-metal heat break would be a consumable? My time spent repairing Dremel 3D45’s in K-12 schools has shown me that there’s a good chance it is!

What’s the symptom?

My Dremel 3D printer will be printing and then all of a sudden the filament stops coming out of the extruder, but it acts like it’s still printing. I will stop it and then unload and reload the filament, and it’ll work for a bit, but then it just did it again.

Many teachers complain that the extruder will jam, or stop extruding filament during a print. A nozzle obstruction is ruled out by the following:

1. The affected printer will extrude normally again after the printer cools down and then is told to extrude again.
2. Replacing the nozzle (link here) does not fix the issue.

So.. What’s going on?

I suppose we don’t know for sure, but my theory is as follows:

When your printer is shiny and new, the all-metal heat break has an opening of a certain, set diameter. Tight enough to guide the filament, but not so tight that it’ll constrict movement when the filament expands as it melts. Let’s call that diameter 2.00mm.

Any time you melt or burn something, carbon is a natural byproduct of the process (think about soot buildup in a chimney after a log fire is made). After miles of filament have been printed, these carbon deposits from the filament begin to cake onto the interior wall of the heat break. Meaning that 2.00mm opening is no longer 2.00mm wide, but perhaps now only 1.85 or 1.9mm wide.

As the filament heats up during the normal printing process, it expands. These warm, thicker areas of the filament now touch the sides of the heat break (whereas before, they didn’t) and create a clog. Also, we submit the carbon-lined walls are now “stickier” than the polished aluminum was.

Why doesn’t this happen with my {insert printer here}?

For the era in which it was manufactured, the Dremel is a bit unique in that it has a full-metal heatbreak. E3D and Microswiss were selling all-metal hotends by this time, but they are more costly to machine than their PTFE-lined counterparts. The PTFE is a slippery material and, as I suspect, isn’t a victim to this sort of carbonized buildup over time.

All-metal heatbreaks allow you to print at higher temperatures, meaning you can use more exotic filaments. PTFE-lined hotends should not print consistently above 235* C, limiting your use to PLA, ABS, and some TPU filaments.

Can I do anything about it?

I’ve tried taking a 2.0mm drill bit and reaming out the heatsink and heatbreak. However.. The marring left on the soft aluminum seems to grab the filament even more and guarantee a clog during your next print. Perhaps there are other ways to ways to remove this carbonized buildup inside of the heatbreak. This Youtuber shows a method where he used polishing compound and a cotton string to improve the quality of a cheap heat break, but we haven’t tested this ourselves.

The Dremel is also unique in the way that the heat break and heat sink are one combined piece. Since this heat break/sink cannot be purchased by itself, the entire hotend assembly needs to be replaced. You can buy one from 3PI Tech Solutions, in their web store.

All in all, the Dremel remains a capable and robust printer choice for any hobbyist, teacher, district admin, librarian, or makerspace! I write this article to give hope to those that might be seeing this issue and have given up on their printer. After all, knowledge is power!

Tell Me About Temporary Clogs, from Shredded Filament!

Reference the graphic below. If your printer cannot feed filament for whatever reason, there is a chance that the drive gear (the motors are quite powerful) just kept going, and shredded a large chunk out of the filament!

Since the filament is now thinner in this area, the drive gear cannot grab it to advance the filament.