Hi all.
So I've been gone a while. But I'm back now. I've spent the last couple months dreaming about hot-ends, what I like, what I don't like. What's worked, what hasn't. And so I took my last design (
http://reprap.org/wiki/Odd_End), and started to update it. The Odd-End currently lives in Madison, where it's been running almost non-stop since July, and I wanted to keep that reliability. But I also wanted to try printing in polycarbonate, which would just melt the PEEK/PTFE thermal barrier. And so I got to thinking about using a stainless thermal barrier, when the thought hit me. Titanium.
Earlier this year, I was dismantling and repairing a stratasys dimension 1200st (which I broke) when I noticed something odd about the extruder design. The heater blocks were made of stainless steel. The cartridge heaters were about an inch from the filament tube, and the filament was being melted at 300ºF, according to the thermocouples. The area only an inch away where the cartridge heater lived was bluing from the heat. Stainless starts to blue at around 500ºF. Clearly, there was some serious thermal gradient going on there, but this machine was designed by people who know what they're doing, so it must be like that for a reason. Best I can figure, here's why. The stainless steel acts like a resistor in an oscillator circuit; it's a damper. It helps smooth out thermal oscillations by slowing down and limiting heat transfer between the cartridge heater and the filament tube. So why not apply that to my new hot-end? Except with titanum instead of stainless, because titanium is awesome.
The nozzle has remained mostly the same. I's short and steep, with a very short extrusion length to reduce the possibility of jams. Oh, and it's also made of titanium.
Because of the high cost of prototyping this, I've decided to try crowdfunding it. I'd really appreciate it if you'd take a look, and I'd love to hear your thoughts.
http://www.gofundme.com/25v5ngThanks!
EDIT: I can English, I promise.
SON OF EDIT: Pictures!
- Thermal barrier. The top section has since been updated to fully threaded.
- Nozzle.
- All assembled!