Notes on the 26-Jul-2008 gathering

I had a good time at the gathering at Olin College. I had to leave by 5:00 but fortunately the software glitches were worked out and the RepRap Darwin started printing around 4:30 so I got to see it in action.

The machine was a joy to behold. Most of the custom parts are currently made of wood which, from what I gather, was cut by hand with a scroll saw. The Z-axis limit switch flag was a gift from someone with a commercial 3D printer and one of the pieces clamping the lift platform was an ABS part printed by the RepRap itself. As tuning progresses and the machine produces better parts the plan is to replace the wood with self-printed ABS parts.

My thanks to everyone who organized the meeting, brought stuff/ideas to share, or just came by to look and learn.

Does anyone else want to say anything about the meeting?

Greater Boston RepRap Users Group, notes on our first meeting

Larry Pfeffer, ursine at gma1l d0t c0m


The "Greater Boston RepRap Users Group" [my moniker] met at noon on 7/26/2008 at Olin College, Needham, MA. Olin student Jim Switzer kindly arranged for the room. We had at least 15 people present
--15 put names on the contact list I circulated, but I think we had several others as well. We had people from Rhode Island to Maine. (Note: if you listed yourself, but have *not* received an email, please contact me, so I can fix your entry.)

The clear highlight of the meeting was Bruce Wattendorf and his son demonstrating the setup and operation of their RepRap Darwin machine (and lots of parts previously extruded.) Among the things I found notable:

Wood (oak and thin plywood) used to make most of the non-metal parts.
Adaptation to "English" dimensioned fasteners.
(e.g. 5/16" for his tie rods, #10-24 UNC for his extruder screw.)
Direct drive for his extruder, rather than angled/cable drive.
Extruding onto a piece of anti-static foam.
Using the original (PIC-based) motor controls.
Heater took a fair while to stabilize at target temp.

Professor Tom Easton talked a bit about the book he's writing on 3-D printing and its impact on society. He also gave out review copies (files, not paper) to some interested people. I gave him my comments and my partially annotated draft of an earlier version.

Various Arduino and work-alike boards were shown, including a Diecimila, a Nano and a Boarduino.

Jim Switzer had some components for his (in progress) Darwin, mainly of steel and Al. He also generously offered Nichrome wire to those interested in making extruders (he scrounged a roll of uninsulated wire.) He also showed his protoboarded stepper control setup, and took us on a tour of two Olin labs, one for robotics, another with a commercial rapid prototyping system (Stratasys?) Observant RepRappers looked at some of the accessories (fabrication bases) and determined that they were made of ABS.

Back down in our room, Bruce W. went into detail on his (direct drive, wooden-bodied extruder, including dissasembling it, so we could see how it worked/how it was made. Bruce molded bearings for his extruder screw, out of CAPA -- very RepRapish. He says these work better than the brass ones they replaced. He also let me measure the Al. coupling that connects his Solarbotics GM3 to the extruder screw. (This looks very similar to the one Nophead made and has documented on his blog.) I'll see if I can simplify the design so it can be made without a CNC mill (change the hexagonal pocket {that holds the bolt's hex head} to a rectangle -- or maybe tap thread for an extrusion stud, if that doesn't cause alignment problems/excess friction.) Bruce also generously gave a couple of us pieces of ABS and CAPA filament -- that'll be a big help (and spur) to build extruders.

Diane Serley arrived, bearing two one-laptop-per-child model XOs -- one with the released software, and another with a development build. These machines do have USB ports, and *might* be able to host the reprap software (didn't try that, memory might be an issue.)

The remaining folks (6 of us) helped Bruce load his Darwin and Linux box into his car, and then went out for dinner and further discussion. We hope to have occasional Boston area meetings (possibly build parties for chunks of RepRap machines) -- ballpark of every 6 months. We may also set up a Google group for Boston-area RepRappers, e.g. for big files, etc. TBD.

Please post additions/corrections to the RepRap forum(s)-- and if you have photos, please post them -- or a link if you put them online elsewhere.

-- Larry

One thing I forgot to mention was the appearance of a pre-release "Sanguino" (http://sanguino.cc/). It's an Arduino work-alike with an ATmega644P processor giving it more I/O pins and memory space. An Arduio Diecimila is almost maxed out by the I/O requirements of the Darwin and the size of the current Single Arduino firmware. The larger processor would provide room for further expansion.

I have not seen any mention of price yet. Since it does not have an on-board USB/serial adapter it requires a serial port or USB/Serial cable.

Hey Guys,

I just wanted to share some of the photos I took during the meeting. I had a great time and hope to do this again in the future.

[picasaweb.google.com]

Hi guys, I'm Paola from Peru. I'm a participant in the International Development Design Summit at MIT my team is prototyping a low cost incubator for infants, my organization is very interested in low cost fabbers and we see a lot of opportunities for prototyping small parts for medical devices, agriculture, etc.

I would like to visit your group at Olin and learn more about rep rap.

Regards
Paola

Christian St. Cyr Wrote:
-------------------------------------------------------
> Hey Guys,
>
> I just wanted to share some of the photos I took
> during the meeting. I had a great time and hope to
> do this again in the future.
>
> [picasaweb.google.com]
> ting07262008


I have visit your provided link and all the provided photo are really memorable.
We must save such type of the photo to make these moment memorable in our life.