Please create a forum for the Greater Boston, Massachusetts area

I just got into an accident on the highway on tuesday going to a meeting at work, so I'm rather busy right now. I'll still try to make it to this though.

Folks,

It's been quiet here, which I've taken it to mean that a noon start is OK.
I've taken the liberty of putting an event posting up:

[boston.garysguide.org]

Please let me know if that needs any corrections.
I'm looking forward to meeting all of you,

Larry Pfeffer

PS *Please* post your ideas about what you'd like to get out of this meeting.
We have some topics, but more would probably be better.

Could we have you guys publish a summary of what you do so that those of us who live to far away to attend get to hear about the neat action at the meeting. ( I live in the Twin Cites, MN)

---

Bob Teeter
"What Box?"

Noon works fine for me.

I'll bring my Arduino Diecimila along in case anyone has not seen one yet.

Noon's fine for me too.

Again, if any of you need directions on the way here, my phone number is 781-540-9824. (maps and such are in a previous post)

See you on Saturday,

-Jim

It was good to meet you all!

Bruce--you mentioned a technique that builds from beneath. Do you have a link for that?

Tom
profeaston@roadrunner.com

Tom, Your book looks incredble and look foward to fully reading it this next week..

the link to the reprap forum on this technology was here

[forums.reprap.org]

Bruce

I just finished a few more aluminum bracket pieces today, and I got a chance to check on the possibility of laser cutting:

So, according to the Olin machine shop webpage, the Legend 32EX Laser Cutter Can:

Hold up to 37

James Switzer Wrote:
-------------------------------------------------------
> The full specs are here :
> [machineshop.olin.edu]

"NO PVC, VINYL or POLYCARBONATE"

Looks like BitsFromBytes drawing "cartesian-bot-5mm-laser-cut-acrylic.dxf" (the main sheet of acrylic Darwin parts) fits on an A2 (420 x 594 mm) sheet. This translates to 16.5" x 23.4", well within the 20"x32" capability of the Olin laser cutter.

The BitsFromBytes design calls for lots of 5mm and 8mm acrylic and a little 3mm acrylic and 5mm "acetal". Fortunately the 8MM is very close to 5/16" and is under 3/8" so it is cuttable on the Olin cutter. 5mm is only a little over 3/16" so perhaps a substitution would work.

I didn't make it to the meeting, but I do live a short bike ride away from a place that sells scrap plastic by the pound and a friend with a laser cutter in his apartment (although he still hasn't gotten it up and running).

does anyone know about what power/wavelength is generally used on a lasercutter? a month or so ago a friend of mine who's doing astro research was asking me if I had a use for a 15 Watt laser, and I'm starting to think of a good use for it...

by the way, I'm in the process of modeling a reprap extruder (v1.1) and creating drawings, since they aren't available anywhere. here's what I have so far: [img504.imageshack.us]

jonored Wrote:
-------------------------------------------------------
> I didn't make it to the meeting, but I do live a
> short bike ride away from a place that sells scrap
> plastic by the pound and a friend with a laser
> cutter in his apartment (although he still hasn't
> gotten it up and running).

Jonored,

Please post the name & contact info for the place that sells plastic by the pound.

Best of luck to your friend with his laser cutter. Please keep us posted on that.

-- Larry

hmm, looks like olin's lasercutter is 75 watts. I'll have to look into this more.

The place is Plastics Unlimited, Inc in Worcester, MA - [www.plasticsunlimitedinc.com] is their website. Right near WPI. They sell off the material from their scrap bin reasonably cheap. It's not a /reliable/ supply, but it's not far to go for me. Of course, it's also entirely possible that they might be able to just produce parts - I'm not sure what their pricing is like for that, though.

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 MIT and learn more about rep rap.

Regards
Paola

Paola Lira Wrote:
-------------------------------------------------------
> 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 MIT and learn
> more about rep rap.
>
> Regards
> Paola

Hello there, Paola,

We aren't at MIT, alas! -- just interested people in the general area. Strangely, we don't have any MIT people (that I'm aware of) posting to this group, yet. I have hope; there was one person at our 7/26 (at Olin College) gathering who gave an mit.edu address.

Low-cost incubators sounds like a very worthy project. One thing to keep in mind is that the quality of parts from repRap machines isn't as good as moulded or milled, so there may be issues of sterilize-ability for repraped parts, due to small inter-layer voids. I'm still at an early stage of learning, and haven't built anything but a small bit of electronics -- though I hope to change that real soon now. Bruce W. is the only local I know of who's got a machine running at present.

Good to hear from you,

-- Larry

Well I am back from Scout Camp..

and some stuff I have found over the last week.

1st. Bits from bytes has updated his site and now has some PDF files under assembly info. ( I spent most of last week trying to figure the .DXF files out.)

2nd. It looks like the main sheet of parts could be printed out on a 1/4 inch thick sheet of plastic.

3rd. Today I went to Lowes on my way into work and found that they carry acrilic and lexan but it is in .080 and .220 thick sheets ( I thought they came in inch not decimal? )

Bruce

singhalaya

I sent an email to Wendy from plastics unlimited and got an answer on prices
of plastic from them.

Clear Plex Clear Lexan



3/16

brucew Wrote:
-------------------------------------------------------
> I sent an email to Wendy from plastics unlimited
> and got an answer on prices of plastic from them.
>
> Clear Plex
>
> 3/16

See [www.telegram.com] .

I spotted it on Slashdot, which referenced Make Magazine. The guy wasn't doing anything illegal, but he has lost an entire basement lab because the authorities got alarmed at all the chemicals etc.

I wonder how they would react to a self-reproducing 3D printer?

a house littered with 1500+ jars/vials of chemicals on the floor, furniture, etc., versus a tabletop machine that fits in a cubic meter and heats a plastic filler rod? i don't think it would be an issue. plus, a machine tool doesn't alert the average person in the way 1500 jars of white chemicals does.

it does bring up an interesting point, though, regarding the "zoning" laws. what's the line between "hobbyist machine tool" and "professional machine shop"? I have a lathe and drill press in my basement along with woodworking tools, but I doubt that would get me in trouble - but if someone had a few mills and lathes, maybe a small CNC machine, could they get in trouble for "zoning" laws?

If people can panic at the sight of chemicals--which, reports so far say, were not hazardous--just because they're chemicals, a self-reproducing machine should scare their pants into the laundry. A RepRap isn't self-reproducing yet, but a von Neumann machine is the avowed goal, and the potential of such a thing is probably scarier than that of those chemicals. Not to mention that it doesn't look like anything these ignoramuses have ever seen before, which may be all they need.

reprap v1.0 is *far* from self reproducing. sure, the concept of a machine able to fully reproduce itself autonomously, from source material to final project, is more "scary" than a retired chemist around a few bottles of asorted supplies. but the average person looking at 1500 random bottles has a "poison! death! anthrax! chemical warfare!" light go off. the average person looking at a reprap in some guy's basement will think "cool! shiny toy!".

although, i do think confiscating thousands of dollars in chemicals from some old guy who knows what he's doing when he doesn't even have anything dangerous is crossing the line more than violating a "zoning" law is.

Comments on slashdot suggest that he was researching ways of pulling some of the nastier pollution poisons out of the environment - which suggests that he may have had some amount of them there. This hasn't, so far as I can tell, crossed out of the realm of "firemen came, found something that could be an old chemist doing harmless experiments, a meth lab, or a chemist working with nasty poisons, and took it for investigation." - they've no reason to simply trust that his lab is what he says it is, and they were invited in (becuase of the fire), so don't require a warrant. The relevant question is whether they return his stuff after it turns out to really be just a chemist properly doing some investigation in his home.

I would be even more surprised if they were to find issue with what is, at present, essentially a homebuilt hot glue gun on a cartesian robot. A reprap doesn't require a chemistry lab to verify it's nature; having been told that it's a hot glue gun on a positioning robot, it's pretty easy to see that it's... a hot glue gun on a positioning robot. No need to trust someone's word that the clear liquid in a little vial is one thing or the other for that. It's even explainable to a non-techie. Shouldn't be a problem.

It's part and parcel of broader problems. I've posted a mini-essay at [technoprobe.blogspot.com].

I thought I'd cross-post these from another thread - some drawings I made a while ago in my spare time of the extruder v1.1 (slightly modified, and some of the dimensions may be slightly off)

[www.mediafire.com]