[Noisebridge-discuss] MakerBot Repaired

[Martin Bogomolni]

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.

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.

The maker bot is a great piece of equipment.  If you don't yet know
how to use it, get a tutorial from another NoiseBridger that has had
some experience on it.

Please don't disassemble the extrusion head.  It's a delicate piece of
work, with a very sensitive thermal-resistor and touchy
directly-soldered connection to the NiChrome wire.

There are a couple issues that need to be addressed in the Maker Bot's build:

The limit switch on the Y axis has the Ethernet side facing up.  It
needs to face down, so that the printing stage can glide over that
area.  At the moment, it restricts the movement of the stage.

The popsicle stick limit switch bars need to be adjusted in the Y
axis.  Right now they are too short, since I didn't take the size of
the stage into account when I cut them.   This will require two
popsicle sticks .. so if you have a hankering for a popsicle .. don't
throw away the stick when you're done.  Give it a rinse, and drop it
off by the MakerBot.

The correct settings need to be determined for the conversion of STL
files to the gcode files needed by the MakerBot.  The default settings
have the head move too fast for the extrusion speed, resulting in
skips and areas where the extrusion bunches up.   The F-speed is
getting set to 1570 and 3300.. however a speed of F800 seems to be
about right for the current setup.  More on this later.