I like direct drive extruders since they are small with less parts however I find them not to be as reliable as geared extruders; with direct drive extruders I had problems with cheap filament since the tolerances are all over the place sometimes the direct drive lacks the power to push the filament through, not a problem with the geared extruder hence when I use good reliable expensive filament I'll go with the direct drive but with cheap filament I always feed it to my geared extruder machine.
Since all geared extruders seem to be large and I wanted something small I made this extruder a 1.75mm geared extruder with herringbone gears that have been reduced to 2/3 it's standard size to make it compact.
Latest version uses a bracket for mounting that allows to remove the extruder easily without tools.
The extruder is working fine however I am still working on it to make it better it might need some changes to please more people like the mounting bracket that might need other configurations for different machines, let me know.
You can always find the latest version and some other goodies in my site here is the link to the downloads area http://infill3d.com/20-downloads
Please let me know what you think, I want to end up using this extruder in a delta bot eventually.
Is a very straight forward extruder, here are the parts you are going to need...
1x Pneumatic fitting 1/8 to 4mm
2x 688ZZ Bearings (Extruder)
1x 608ZZ Bearing (Idler)
2x M3 Washers (Springs)
2x M3X45 Socket screw (Extruder to idler)
4x M3X8 Socket screw (Motor)
2x M3X16 Socket screw (Idler)
4x M3 Nuts (Idler, spring screws)
2x 1/4" x 1/2" x .035" (6.350 x 12.7 x .889mm) Untility comp springs (Extruder to idler)
6x M8 Washers (Hobbed bolt)
1x M8 Nyloc Nut (Hobbed Bolt)
1x Hobbed bolt (distances between the center of the groove and the base of the head should be 18.5mm +/-)
Be careful when you are treading the pneumatic fitting is easy to strip that area, I wanted to beef it up but space is limited in that area. It works fine just be careful not to apply too much force that could strip the plastic.
When mounting the motor notice the notch on the big gear is there to give access to the screws of the motor align the notch with the screws holes.
I debated about using a standard hobbed bolt however that would have made the extruder larger and I wanted it to be small hence I went with the current hobbed bolt (check picture) with that said if enough people asks for a regular bolt design I'll make some changes.
This version is in 1.75mm, I want to make a 3mm version however I been busy with other obligations, is there more people out there using 1.75mm or 3mm? I'll get around to make the 3mm version hopefully soon, let me know what you folks think.
Please send me some feedback since I want this extruder to go into the delta bot that I am working on.
Thank you everyone for your help.