Litterally, there is nothing on this printer you couldn't do yourself - just as good - with nothing more than a 3D printer and a laser cutter.

They used printed gears on a $4k printer?

They absolutely did.

The mount and tension lever are made from ABS, but the gears are made from Nylon.

On a side note, the quality control on this stuff is really not that great for a $4,000 printer. It was not printed with 100% infill, so the screws sink in a good bit. The nylon gears warped while printing. The bottom and/or top layers of the ABS and Nylon parts are not completely manifold (flow rate issue). The part pictured is the right extruder, but the left extruder mount arrived cracked (and still is) where one of the nuts are. Design is good, but the print quality is just not really what you'd expect for so much money...

Anyway, here are the pictures:

grob wrote:

This is the idea, but it locks open instead of having to hold it open.

My Airwolf has a neat setup on the extruder motor... it has an arm that is spring loaded and locks with a pin. You pull the pin out and the arm releases. Here's a really good picture from google (I'm not in the office right now) - I would love to come up with something similar but their design is "proprietary" and they won't give out the STL's. I suppose I could take it apart and reverse engineer it, but that's a project for another day...

There are many similar designs on thingiverse.

This is the idea, but it locks open instead of having to hold it open.

My Airwolf has a neat setup on the extruder motor... it has an arm that is spring loaded and locks with a pin. You pull the pin out and the arm releases. Here's a really good picture from google (I'm not in the office right now) - I would love to come up with something similar but their design is "proprietary" and they won't give out the STL's. I suppose I could take it apart and reverse engineer it, but that's a project for another day...

This is why I like spring loaded tension arms. They supply enough tension to feed normally but you can push them down out of the way to feed filament by hand when needed.

This is the idea, but it locks open instead of having to hold it open.

I'm really interested in seeing what you come up with! Be sure to post it. I found lots of designs on thingiverse but I have somewhat of a problem finding anything compatible with 3mm... I might end up with designing my own. The one I am using now was designed for 1.75mm and I just drilled it out to work with 3; that's why it's too tight to push through by hand, even with the bearing released.

I've been trying to fix up an extruder with a release lever thing that pulls the bearing off the filament. Have one running at the moment, but it's a bit rough still and I have some way to go. I know something like the lawsy mk5 arm design allows you to just pop the spring out, but I find this quite fiddly to re-set.

Just seen a design with the filament path through the arm so a release would pull it away from the gear entirely, which would be even less fuss to feed by hand. Going to try a version of that idea next...

All humor aside, I learned a valuable lesson today. Not sure how to get around it but I won't be loading filament with my extruder anymore.

Let me explain - on my new printer, I have a bowden setup. The hobbed gear is too tight against filament to push it by hand so what I usually do is tell E1 to extrude 900mm and that's enough to feed through the entire PTFE tube and purge 100mm.

However, today as I was loading a new spool of PC filament (at 300C) it got stuck on the lip of the heatsink. I noticed it because the extruder started clicking; I knew what happened, so I went over and moved the PTFE tubing a bit to help it out. Apparently it had built up some pressure because the instant I did, I heard a loud POP and the nozzle squirted out molten PC at enormous force. It had enough force to hit me in the face, a full arm's length away and a foot or two above the nozzle, barely missing my eyeball by a fraction of an inch. Maybe it was a coincidence, maybe not, but you can bet I'm going to come up with a better loading solution!