Friday, September 28, 2007


The extruder lives - again

And the Darwin produces a minimug; well, nearly. It's not watertight and has a lot of stringy bits in it. Not far off though. The Z axis is starting to smooth out a bit and the extruder is behaving very well now, if a little slower than I'd hoped.

The blown nichrome was right on the surface where the wire entered the plaster jacket. I suspect metal fatigue. Still, I dug out a few mm of nichrome (the 'pelican' insulation had disintegrated near the break) from the jacket and fired it up again. Heh, not forgetting to do the PTFE clamp back up...

[Breaking News: Watertight minimug now exists. Pictures of traditional toasting tomorrow.]

Must also pay some attention to family this weekend.

Vik :v)

Where did the parts for your Darwin come from? I'm guessing from the colors that they were made from some other FDM process.
Is the filament on the other side of the extruder screw bearing against plastic? I'm wondering if the extruder screw might work a lot better if it was bearing against a gear instead?

Or maybe ... maybe since the filament has a fixed size, you could use two worm gears, one of which was driven and the other running freely. The motor would drive the worm, which would give you one more level of down-gearing.

Then you wouldn't have the problem of the PLA getting ground up by the screw.
Adrian has a two-screw version in mind, but for the moment it bears against plastic and this works quite well - keeps the parts count down too!

Vik :v)
> Where did the parts for your Darwin come from?

We have distributed parts to the core developers so they can build their own Darwins. But we are also working on moulding sets of parts in epoxy to get people going in the time before there are enough machines out there to supply the demand themselves. Keep watching the RepRap online store ( for news/availability.
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