[Noisebridge-discuss] MakerBot Repaired

[Jonathan Lassoff]

Excerpts from Martin Bogomolni's message of Mon Aug 24 05:02:39 -0700 2009:
> I repaired the NiChrome heating element, and rewrapped the extrusion
> head of the Maker Bot.  The ceramic tape insulation was pretty badly
> damaged, so I only wrapped a minimal amount around the printing head,
> enough to give it some temperature stability.   It's been securely
> wrapped in Kapton tape, and tested by printing out a shot glass and a
> lego brick.

Woo hoo! Thank you muchly for working on this. At the very least, it's
appreciated by me, and I would guess others that like to print from here
as welll.
 
> The Mark 3 extruder seems to have some issues with maintaining a
> steady bead size.  I expect this is due to not having sufficient
> thermal mass to hold a steady melting temperature at the nozzle tip.
> Extra insulation will help this.  Also, the feeder seems to have some
> issues as well so some more experimentation with feed rates, head
> temperature, and adjusting the feed mechanism might be needed.

I wondered something similar. Last I used it, I also found that the extrudate plastic
kind of drips out a little after the pinchwheel is shut off. I suspect
this may be due to a combo of a hot element and a very tight/snug bolt
holding the free-spinning pinchwheel gear against the plastic.

Maybe it's holding the plastic at a slight plenum/pressure inside the heating
element?

--j