Here’s a video I recorded this morning showing our worm drive extruder in operation:
We’ve found this design to be extremely reliable, powerful, and smooth running. And it uses the same NEMA 17 stepper motor that we use for all other machine axes.
The only improvement I’d like to see is the addition of a spring loaded pressure wheel, rather than the fixed position setup we use.
I’m currently assembling a new version that has a similar design, but is more compact. More pics to come.
UPDATE: I should mention that this was inspired by NopHead’s worm drive extruder
really fantastic work. i’m consistently impressed when i check in. keep it up!
i presume the more compact version puts the motor on top and runs it in reverse to what is doing now? still, fantastically simple, once at gear is fabbed.
also, have you considered putting two gears onto that axle? allows for an alternative ratio if necessary and removes the grease fouling the feedstock issue.
Andres- yes, I have thought about adding a second drive gear. The result would probably be ideal, and very similar to NopHead’s worm drive extruder. It would remove the oil fouling issue and allow for other drive ratios. The only issue I’d have with it is that these gears are pricey little buggers, ~ $15 each. The current setup lets me get away with just two of these off-the-shelf components.
Maybe the oil isn’t an issue. I’ve seen people run the filament through sponges soaked in oil to lubricate the system. Maybe contaminating your filament with oil actually helps.
When running it at such a high throughput, do you have any issues with the filament not having time to properly melt, and then jamming in the hot-zone? Did you have to modify the heating system to “keep the heat up”, or run at a hotter temp, or similar?
Do you have a source and part numbers for the gears? I usually buy from Stock Drive, but I am having trouble figuring out what is best.
How do you make it do those retractions? Is there a a Skeinforge setting for it? Your extruder is very impressive.