A summary of recent events

[Tim Schmidt]

There's been a lot of activity recently, but not much of it has shown
up on the list... so I decided to write up a quick summary.

Nick (mcc...@gmail.com) has been working on a new unified electronics
board. He's nearly done, and his documentation is here:
http://objects.reprap.org/wiki/Gen2Backplane It looks promising, at
an estimated cost of $100 for a fully populated control board. It's
also quite small, making it ideal for use with the mini-mendel!

I got frustrated with existing 'hot end' (the nozzle, heater barrel,
thermal barrier, etc.) performance and reliability. In response, I
designed a new hot end based on the most recent BitsFromBytes hot end.
I managed to find some inexpensive liquid spraying nozzles from
McMaster Carr in 0.254mm, 0.508mm, and 0.762mm sizes which work well.
Other bits of the hot end include a PEEK thermal barrier, and an
internal PTFE liner that runs from the entrance of the hot end to the
tip of the nozzle. I've got 50+ hours of printing on my prototype hot
end, and have given copies to Nick, Devon, and Dean. Nick and Devon
have reported very positive results, and Devon's due to install his
soon. It looks like a big improvement in reliability.

One of our newest group members, Dean (dean....@gmail.com) who has
been building our group's first child machine - a mendel who's parts
were printed mostly by Nick, with a few contributions from me - has
got his machine printing. He's still working on improving print
quality, but along the way has figured out how to drive steppers from
the extruder controller board using the latest Makerbot firmware,
without any dirty hacks.

Also, Dean and Devon have started investigating laser sintering as a
new method of printing. Devon has purchased a small ball mill, and I
sure will soon post some news of how well it powders various plastics.

In other news, I'm attempting to build a machine capable of printing a
mendel in a single print - a 14 x 22 inch build area. Purchasing
parts today, and I hope to have the structure together by the end of
next week.

Things are happening quickly... if anyone is interested in any of
these events, ask for more information on the list, and the relevant
folks should come out of the woodwork to offer some insight.

--tim

[Dean Piper]

-My laser hasn't arrived yet but should soon. .
-Mendel prints are getting better really fast using all the newest
makerbot firmwares with no hacks. If anyone needs help let me know.
-Changed my Mendel bed from MDF to Acrylic and it's working much
better to stick the PLA down
-The new nozzle from Tim has about 15 hours of printing in and has yet
to fail since I got it put together properly with cooling and
insulation, both are key!
-I'm finding that the electronics get a lot hotter than one would
want. Mostly due to the high power values of my NEMA 17's, they can
draw up to 2A, I've had to put a lot of heatsinks on and am using
cooling fans and not it works fast and smooth
-The heatsinking is also key to using a stepper on the 2.2 extruder
controller and using a lower PWM, I'm at 160PWM and 20RPM while
extruding, at this point anyway, I plan on going to a lower PWM still
yet to get rid of a little of the noise it creates when compared to a
stepper drivers

Does anyone have any suggestions on a decent piece of sotware to
manipulate my STL files? I don't like AOI and the Siemens suite is a
huge install and not very legal, lol. It also has problems opening the
files created with academic licenses.

-Dean

On Mar 12, 3:50 pm, Tim Schmidt <timschm...@gmail.com> wrote:
> There's been a lot of activity recently, but not much of it has shown
> up on the list...  so I decided to write up a quick summary.
>
> Nick (mcc...@gmail.com) has been working on a new unified electronics
> board.  He's nearly done, and his documentation is here:http://objects.reprap.org/wiki/Gen2Backplane It looks promising, at
> an estimated cost of $100 for a fully populated control board.  It's
> also quite small, making it ideal for use with the mini-mendel!
>
> I got frustrated with existing 'hot end' (the nozzle, heater barrel,
> thermal barrier, etc.) performance and reliability.  In response, I
> designed a new hot end based on the most recent BitsFromBytes hot end.
>  I managed to find some inexpensive liquid spraying nozzles from
> McMaster Carr in 0.254mm, 0.508mm, and 0.762mm sizes which work well.
> Other bits of the hot end include a PEEK thermal barrier, and an
> internal PTFE liner that runs from the entrance of the hot end to the
> tip of the nozzle.  I've got 50+ hours of printing on my prototype hot
> end, and have given copies to Nick, Devon, and Dean.  Nick and Devon
> have reported very positive results, and Devon's due to install his
> soon.  It looks like a big improvement in reliability.
>

> One of our newest group members, Dean (dean.pi...@gmail.com) who has

[Tim Schmidt]

On Fri, Mar 12, 2010 at 4:22 PM, Dean Piper <dean....@gmail.com> wrote:
> Does anyone have any suggestions on a decent piece of sotware to
> manipulate my STL files? I don't like AOI and the Siemens suite is a
> huge install and not very legal, lol. It also has problems opening the
> files created with academic licenses.

I continue to have great success with HeeksCAD. It's FOSS, based on
the OpenCascade libraries, and works great with STLs. Figuring out
how to export to STL was interesting... you just use File -> Save
(which unlike other applications, always opens the file picker
dialogue), then name the file with a .STL extension. Heeks does the
rest. Skeinforge appears to have no problems consuming the STLs heeks
generates.

--tim

[stmaus]

Dean Piper wrote:
> Does anyone have any suggestions on a decent piece of sotware to
> manipulate my STL files? I don't like AOI and the Siemens suite is a
> huge install and not very legal, lol. It also has problems opening the
> files created with academic licenses.
>
> -Dean
>

I'm using ViaCAD by Punch! on my Mac and it is great! Only $99 and works
on Windows/Mac. It handles fully parameterized solid models and talks
well with STL.

I'm using it with the Mendel STEP files to begin my SLS based Mendel.

It will keep me going till FreeCAD becomes truly viable.

-=[Devin]=-

[Tim Schmidt]

I just finished re-wiring nearly my entire machine... I moved the
extruder controller board off the print head, and attached it to the
body of the machine like the rest of my electronics, ditched the 4th
stepper driver board I had been using with my hacked firmware, updated
my extruder controller to Makerbot's v1.8 firmware, built a dedicated
machine to control the thing, installed the entire toolchain, and in
the process managed to replace the extruder nozzle I'd managed to
break by driving it into the build surface on a previous print. I've
done some test extrusion, and everything seems to work.

I have to run the extruder controller's PWM value at a minimum of 200
in order to drive PLA in my current extruder w/ my NEMA-23 motor. At
that duty cycle, the chips get quite hot. I'll definitely have to
build and attach a small heatsink and fan to them somehow before
printing.

Thanks for the pointers Dean!

--tim