I have been reasonably impressed with my Lulzbot Taz 5's reliability and performance with the single extruder tool head, that is until it failed the other day fairly early on in a 10 hour print. I ran the print overnight and made sure it started out ok. I came back in the morning to find the printer just moving around in air. Turns out the extruder jammed.

I experienced this failure mode with the dual extruder. Somehow the filament melts and gets stuck above the heat sink. If you try to just heat it up and extract the stuck filament nothing happens. The only solution is to take the tool head out of the machine and drill it out. So I bought a second single extruder and decided to use my jammed one for R&D.

Inspired by PC liquid cooling systems, I decided to see if I could design a liquid cooled tool head for my printer. My initial thought was to use a system that didn’t have a pump and relied upon convection to keep things cool, but eventually I decided to give the pump a try since flowing fluid would carry heat away much more efficiently and cheap pump/reservoir combos are available on amazon.

I was going to design and machine a new heat sink for the extruders but after collecting some temperature data I found the heat sink to hover around 50 to 60 degrees C which is well within the safe operating temperature of some 3D printed materials. My idea is to have a "jacket" that slips over the heat sink and is essentially glued in place with RTV for water tightness and to allow some flex as the materials expand and cool and then have water flow into and out of the jacket keeping everything nice and cool. It will pass through a radiator with a fan and then back into the pump.

As far as I know I don’t think anyone has tried this (maybe for good reason).