Contacting Fab@Home people to help making Darwin parts

Hi Reprappers,

I was wondering if some of you know some people at fab@home project - [www.fabathome.org] - to help us making the first parts of Darwin machine until we all get enough parts to replicate ourselves?

That could be a good collaboration, open-source projects helping each-others

Do you know any limitation in this idea?

Cheers,

Alex

Maybe I've not paid close enough attention to the fab@home site in recent weeks, but the last time I looked I didn't get the impression that the fab@home machines, the few that are working in the field, that is, were capable of making parts of the sorts of plastics that we use in Darwin.

Has something changed?

Hum... that's the kind of limitation I was looking for, too bad :-/

I dont know, reading their site it says they can print in gypsum. If I can get a gypsum part I can certainly try and impregnate it with support resins. We use plaster in our 3d printer and then flood fill the pourous parts with either polyurathane (one parts are available at hardware stores) or epoxy (expensive but it makes a part as hard as concrete). I need to go to the hardware and get some joint compound anyway to fix a drywall hole, I'll get a little extra and see what I can do.

Hmmm, $3K for a fab at home unit. I may want to talk to my wife this evening.

Mike

Well, the first results are in. I made a standard test piece out of joint compound and then impregnated it with polyurathene. The results were a tensile strength of about 120psi and from that I can assume a compression strength in the 1000psi range.

Not concrete but more then strong enought to do what we need done. And one part poly is available for about $30 a gallon at any hardware store in the the states (I dont know anything about worldwide availability). Midwax high gloss clear coat is my personal favorite. It you use one part rather then the accelerated two part stuff that I am using I would suggest a slow low bake or let the thing sit for a couple of days. You MUST use oil based clear or the water in the clear will dissolve the joint compound. Based on my results, one gallon would be more than enough to impregnate an entire Darwin.

An interesting side note, after baking and impregnating with polyurathane you could use this material as a mold and pour aluminum if you wanted to. It would smoke like crazy but it would hold.

Mike

The thoughts and ideas expressed in this post do not reflect those of my employer and are intended only as communications between individuals. Any attempts at implement are at your own risk

Edited 1 time(s). Last edit at 09/12/2007 09:27PM by ohiomike.

i think this would be a great idea. personally, i think their project is great and would love to see some bridge building happen. getting parts made would be a very excellent way to make it happen.

is anyone interested in contacting them? i'm so busy with various things that i dont really have the time, but if someone else out there has the time, it would be much appreciated. the parts we'd need printed are on sourceforge. it would probably be best/easiest to start with the extruder and then work up to the more advanced parts. if it works, then perhaps we could get them to be a supplier for the RRRF store! that would be very cool indeed.

I posted an inquire to their forum but I am going to try and find a email for someone that is more familar with who has working systems. If you have any suggestions for who I could talk to drop me a line.

Mike

The thoughts and ideas expressed in this post do not reflect those of my employer and are intended only as communications between individuals. Any attempts at implement are at your own risk

Edited 1 time(s). Last edit at 09/12/2007 09:27PM by ohiomike.

unfortunately i dont know very much about their project, nor do i know any people involved with it. i think posting on their forum is definitely a good first start.

SUCCESS!! Well at least in part.

I got in contact with the head of the project at Cornell, and he said that while he cannot engauge in commercial activities as part of a univerisity project, that he will assist us in the creation of a proof of concept run. He requests that we wait and see if any of the other fabbers would be interested prior to him starting testing.

Basically if he assists us it will be only to the point of creating a verified blueprint by which other fabbers can create the parts. After that we will need to deal with the fabbers individually since they do not have a conflict of interest.

Mike

The thoughts and ideas expressed in this post do not reflect those of my employer and are intended only as communications between individuals. Any attempts at implement are at your own risk

Edited 1 time(s). Last edit at 09/12/2007 09:24PM by ohiomike.

great news! please keep us posted on further developments in this arena. hopefully we can get some parts printed off and working from Fab@home. That would be something special.

I met Hod Lipson of the Fab@Home project at Scifoo last weekend. We had quite a conversation and I think that I now understand the differences and similarities between our projects. His Fab@home goals lie in using a wide range of materials and using off-the-shelf parts. The RepRap Project - at least initially - wants to limit the range of materials for simplicity and use as many self-fabricated parts as possible.

There are at least two areas where there is significant scope for collaboration: The creation of multiple material file formats and the printing of functional circuits. I've talked to Hod about this, and discussions are ongoing.

Vik :v)

i think it would be amazing if once they have on our our extruder heads, they could use it to print out darwin parts to help us bootstrap. i would love to see such a collaboration.

A lot of the issue is that they dont have many more systems running than we do. I have been trying to get in contact with them again to set up a proof of concept printing of some parts but so far no responce. I am hoping that this is just because of the summer break but I will try again in a month or so and see what happens.

Mike

The thoughts and ideas expressed in this post do not reflect those of my employer and are intended only as communications between individuals. Any attempts at implement are at your own risk

Edited 1 time(s). Last edit at 09/12/2007 09:08PM by ohiomike.

Is it reasonably certain that the Darwin extruder, attached to a reliable cartesian robot, would be capable of printing the necessary parts?

I'd be willing to build a Fab@Home Model I, retrofit it with the RepRap extruder, and dedicate it full time to printing RepRap parts, if there's enough interest to offset most of the expense.

Assuming it's possible, ten people willing to commit to buying a set of plastic parts at $200 would be good enough for me. I can work on this project nearly full-time, so this could move along pretty quickly.

I have a Darwin extruder attached to a reliable cartesian robot. It will probably take me a couple of weeks to find out whether it works. If it does I will make parts for people at cost but I suspect that the current part designs cannot be made with the current software and HDPE.

Edited 1 time(s). Last edit at 08/17/2007 09:20AM by nophead.

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[www.hydraraptor.blogspot.com]

In that case, I'll just sign up for one of yours, if you're willing. :-)

Well the deal is on receiving a set of parts you use them to make a machine and use that to make two sets of parts to pass on to two other people. That way we conquer the world in a short time. That's if it works!

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[www.hydraraptor.blogspot.com]

Understood. What I mean is, I'm not going to spend $2.5K on retrofitting a Fab@Home unit, if it's going to be unnecessary. I'm happy to help make parts in any circumstance.

I'm trying to get my local university to help with the printing; if i printed one complete set of parts, how many cubic centimeters of product would be produced? I need a good idea of the total volume so the running cost can be estimated. thanks!

IIRC, the Darwin parts took something like 1.1 kg of ABS or, assuming ABS has the density of water, 1100 cm^3. That's about 70 cubic inches and the last time I heard, which was in February, Stratasys' ABS filament was selling for about $4.50/cubic inch. That would mean that you'd be looking at $315 to get a parts set made.

One thing to keep in mind is that Darwin parts at the time I got that 1.1 kg number did not include the parts for the support material extruder Adrian has developed in the past few months. That's a pretty important addition that I am sure you will also want, so maybe you'd better add 5-10% more to that 1.1 kg figure. I expect that there will be a different mounting plate in there, but I don't know if the support extruder and an updated mounting plate have been uploaded to the STL repository yet.

As well, I understand that Darwin will also include a docking system which one of Adrian's graduate students has recently got running properly. The word I had was that the idea was to allow for Darwin to be able to work in two polymers. As well as guessing at how many extra cubic inches that would take it would imply that you would need two parts sets for the Mk II instead of one.

Doing a thumb suck, I'd imagine that if you budgeted about $375-400, you'd have a full, up-to-date parts set for Darwin. That's a hell of a lot better than the $2,500+ price that a commercial prototyping company would be likely to charge you.

Mind, when we have Darwins running we can expect that $375-400 to drop to a tenth of less of what you'll be paying. It's a chicken and egg thing, though. You've got to have those first Darwins before you can enjoy those low, low printing prices.

Edited 2 time(s). Last edit at 08/19/2007 09:25PM by Forrest Higgs.

One of my immediate goals is answering this same question of volume precisely in the near future. I'll let everyone know when I do.

My hope is that the regular extruder will be able to print the support one, so I'll be able to skimp and not have the support extruder commercially made...