Tuesday, August 11, 2009
Simple Pinch-Wheel Extruder Plans
Following up from my recent post [here] about our success with a simple pinch-wheel extruder (made from things around the workshop), some folks suggested it would be a good idea to post plans since the design seems both functional, and doesn't necessarily require any printed parts or precision metal working.
The measurements will depend on the toothed gear and idler pully's that you use -- we don't have any part numbers for ours, since they came from the "random bits we've saved" box. The extruder's DC gearmotor is the same used in the Makerbot Plastruder, which they list as a Kysan 1156006 [Makerbot Partslist] [Makerbot store link].
Here are some illustrations:
And a few pictures that focus on the extruder:
Hope that helps! :)
i also managed to measure the extrusion rate: at full speed, the extruder used 20mm of the 3mm diameter ABS filament in about 18seconds. that makes the extrusion volume at about 7.85mm^3/sec. (i'm not sure how that compares to other extruders, i haven't been able to easily google the extrusion rates of other popular extruder designs).
hope that helps! :)
My partner Adam did some quick tests:
Extruding at ~210 degrees C:
100mm/84.9sec = 1.18mm/sec
Without a nozzle, same extruder, same settings:
100mm/79.1sec = 1.26mm/sec
These are the feedrates of the 3mm diameter filament, not any extruded plastic.
1 - replace your flat plastic backplane with short length of aluminium angle - ie it's shaped like an L.
2- the vertical section of the L holds the motor just like your backplane, and the horizontal section has a hole/s to bolt the 'hot section' to.
3 - my "transition zone" (ie the PTFE zone) is squeezed between the horizontal arm of the L and the washer-with-three-bolts trick seen in http://farm4.static.flickr.com/3400/3204174499_6af75c3f0f.jpg?v=0
hope my description makes sense. :-)
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