Wade's Geared Extruder
Release status: Stable
Characteristics/advantages of this extruder:
- extrude/print at high speed;
- good for use with a low torque Nema 17 motor;
- no need to glue the PTFE barrel;
- no need to use expensive metal gears;
- no need to use expensive and complex tools - just one hand drill, a file and a M3 tap;
- no need to make splines on motor shaft;
- no need to do two precision flats on motor shaft;
Photos from Thingiverse , of other people's copies of this extruder.
Here is a link to a previous version of this page that describes an earlier version of this extruder that uses an M4 shaft, and includes more details about pull testing the two versions: "Geard Nema 17 Exteruder Version 0.5"
Mechanical Construction
Material
- 3 X 608 bearings (Skateboard bearings);
- 1 X M8X50 bolt;
- 1 X M8 nut (Nylock works better, but a pair of nuts will also work);
- 4 X M8 washers;
- 1 X M8X20 piece of smooth bar, threaded bar or a bolt;
- 4 X M4X45 bolts;
- 4 X M4 nuts;
- 4 X M4 washers;
- 4 X M3X15 bolts;
- 2 X M3X35 bolts;
- 8 X M3 washers;
- 4 X Springs - 1 mm diameter wire, wound to an OD of 10 mm, with 4 active coils. For a given filament drive force, you'll need about twice the spring force - ie, if you want 100 N of filament drive, your springs need to push with about 50 N each.
Printed Parts
- 1 X M8_Extruder_Block_3.stl
- 1 X M8_Extruder_Idler_Block_2.stl
- 1 X 11t17p.stl
- 1 X 39t17p.stl
Motor
- 1 X Nema17 high torque (5 kg*cm is nice) Kysan 2BYGH4803 works well
How to build it
I used a hand drill and a file to cut the slot, then hobbed it with an M3 tap mounted in the drill, using bearings mounted in a vise to let the bolt spin - see the next videos from Casainho:
So far so good!
Here's the test jig:
This extruder hit 16 kg - here's the results: M8 shoulder bolt - 7.0kg, adjusted tension, new springs - 11.0 kg,
Tightened springs, 3 trials:
15.5 kg, 16.5 kg, 15.25 kg
The final failure mode was the stepper running in reverse, as opposed to the filament slipping. That's quite promising.
3D CAD Files
Here's the design files for the latest version:
- extruder body and idler block: File:M8 Extruder 3.zip
- 11 tooth drive gear and 39 tooth M8 hub driven gear: File:M8 Gears.zip
- alternative 11 tooth gear that should be better: File:Nophead gear with setscrew for wade extruder.zip
- (if you do not want to use a vise to support the M8 bolt) use this support for bearings, needed when using M3 tap: File:Pinchwheelwormdrilljig.zip
- You can also get the files from thingiverse although they may not be the most recent.
Finally, here's a spreadsheet to help calculate the proper feedrates: media:feedrates.ods | media:feedrates.xls
