Saturday, June 10, 2006


Video of Da Witch in action

There have been a few requests for some video, so here's a 2.7MB straight MPEG, about 24s showing the deposition process in action on the Da Witch prototype. This is a still taken from the video and the object being deposited:

The hexagon is being deposited with a 0.8mm nozzle running at 140C driven by the latest GUI. The mess on the left of the new glass deposition surface is where the nozzle moves to dribble when it reheats. The glass is held snugly on the stage by cunningly-shaped self-adhesive foam strips.

Here's a shot in close-up of the plastic still hot and transparent, exuding from the nozzle in the second layer of a cross-hatch pattern:

So far the most complete layers we've deposited is 4, but this has been done a few times now and is no longer an unusual or particularly tricky event. Now it is repeatable, experimentation to find the best nozzle can begin changing one factor at a time. That's science :)

Vik :v)

Actually, if you're planning to change lots of factors eventually, you might not want to change just one factor at a time. You could make a big multi-dimensional table of procedures, and try out the corners first, rather than starting at one corner and moving away from it gradually. You just have to be careful with the statistics you use to control for one factor versus the other.
Even if I just change one thing - say the height of a layer - the width changes too, and the density changes, the heat capacity of the completed work changes, and that's before we consider the quality of the last batch of feedstock...

The big problem is trying to minimise them all. I'm a practical and methodical old luddite, I'm afraid, and try to avoid as much change as possible until I determine what the game is. The bonus here is that I'm delighted merely when things happen the same way twice :)

Vik :v)
That's just brilliant, Vik. You have my blessing to pester me repeatedly to finish the STL-slicing code...
It's so wonderful to watch things come together like this!

Watching your video clip I feel a little better about the racket on the Godzilla's video clips. :-p
This is looking fantastically promising! I'm also pretty amazed how fast this project is progressing.

I've been wondering about the future of disruptive technology such as this. If anything approaching a worldwide revolution occurs once the RepRap becomes viable, and people are ultimately able to make a huge variety of products on a whim, one possible outcome would be something resembling a symbiosis of current capitalist industry for those highly advanced products (eg microchips) that the first several generations of RepRaps would never be able to produce, and something rather like an anarchy (in the true sense of the word) of individuals linked and united only by social ties, and not necessarily by employment in large organisations. Gordon Rattray Taylor envisioned something like this which he referred to as paraprimitivism, although in his prediction people were freed to form smaller social units by a partial abandonment of the pursuit of technology, as opposed to an empowerment of individuals to develop technology entirely individually. I wonder, however, whether such a "degradation", for want of a better word, into smaller technologically inclined organisations might not impose a limit on the size of potential technological projects considerably smaller than is currently achievable. Could such a society pursue a space program, for example? Even modern capitalist societies could be said to struggle when it comes to space projects, despite offering a comparatively large heirarchical organisation to support such projects - one might suggest that even that system was only able to pursue such a colossal project (in terms of human cooperation) as the moon shot with the additional galvanising political force of the cold war space race. Could such a level of cohesion ever be achieved once the majority of people with such technological skills are able, more than ever before, to follow their own inclinations as opposed to the collective decisions of, say, a large heirarchy such as NASA, ESA or Energia? I am somewhat optimistic - the open source system has already proven itself the equal of groups like Microsoft in the production of operating systems, but physical projects present more problems. For example, even if a sufficiently large group of RepRap developers (I think we may need some new terminology soon! Some simple word analogous to "coder", "hacker" or "programmer", applied to the creation of hardware using RepRaps?) could form and coalesce sufficiently to design such a massive device as a multistage rocket, and divide labour sufficiently to produce all the component parts using their fabricators, there are issues such as transportation to a single assembly area, and carrying out the assembly itself.

Needless to say, such a scenario is decades or even centuries away, and a space program is of course the most extreme example imaginable (which is of course why I chose it), but I wondered if anyone else collaborating on this project has any similar inclination to long-term musings. Anyone care for a discussion? :-)
***Now it is repeatable, experimentation to find the best nozzle can begin changing one factor at a time. That's science :)***

Naah, that's just engineering! :-p
Your space program example is wonderful precisely because it too is going the same way as RepRap and open-source. The Ansari X Prize for the first private spaceflight has just been won by - essentially - a bunch of hackers working out of a garage. Give those people a hundred RepRaps and they'll be back to the moon before you can say "NASA overheads".

Other people are working on home fusion reactors - Google "Farnsworth fusor" to see. (And when I say "working" that's exactly what I mean - check out the neutron counts from some of these people's basement experiments.)

I think we are at a tipping point in history more profound even than that which will occur because of climate change. Engineering is coming home...
***Other people are working on home fusion reactors - Google "Farnsworth fusor" to see. (And when I say "working" that's exactly what I mean - check out the neutron counts from some of these people's basement experiments.)***

The Farnsworth Fusor is one of Brett's favourite hobbies. Have you got a link or two on that?
I've already come across several farnsworth fusion reactor sites, and of course virtually come as close to falling in love as you can do with a hunk of metal! They're understandably reluctant to post any equations or detailed construction plans, of course, to make sure that nobody who doesn't have a very thorough grounding in the subject can build one and unknowingly irradiate their neighbourhood ;-) Pity nobody's achieved breakeven yet, but I've had a couple of novel ideas I may experiment with once Ive got my foundry & machine shop sorted out. I guess after working with polymorph it would be dead easy to reprap using very low melting point wax, to make complex lost-wax metal moulds!

That reminds me, I recently salvaged a decent oil diffusion pump from Uni , a necessary component for many high tech "hobbies" such as building fusors or gas lasers. I was planning to reverse engineer it at some point and try to produce plans so anyone could reprap one, since they're so horribly expensive and also so very useful for people like us!
Nice. Would it be OK if I posted the video on YouTube?
Yup. Bob Bussard thinks he has a way to get fusors to break-even. The problem, of course, is the interception of a small fraction of the ions by the inner grid. Bussard recons he can deflect them round the grid using magnetic fields, in much the same way the Earth's field deflects the solar wind.

***we may need some new terminology soon! Some simple word analogous to "coder", "hacker" or "programmer", applied to the creation of hardware using RepRaps***

I believe the term Neal Stephenson used in The Diamond Age was "artifex". Does that suit?
I've actually used the term Artifex in the household, being something of a Diamond Age fan.

Steve, feel free to YouTube it. Let me know th URL :)

Vik :v)
The space industry is one of the few industries that will be interested in our kind of fabricating device, because one fabricator can replace a whole truckload of spare parts in orbit - and reaching orbit is damned expensive.

Most other industries would not back RepRap, because once RepRap exists, their good become comodity items.

Vik :v)
The only people to really get hurt are the emerging manufacturing economies like China, Malayasia and Mexico. Stateside companies mainly do designs any more and put them out to bid for manufacture in places like China.

What IS going to suck for US companies is when open source technology products start competing with corporate designed goods. It's going to be Linux and the Cathedral vs the Bazaar all over again.

The people who are going to clean up are the folks making the feedstock polymers and filaments for repraps and the bits that are just too fiddly to do with a reprap, like IC's, for instance.
Here's the video.
if I recall, the term "hacker" originally was a reference to a person particularly adept at creative solutions building model trains in a particular circle at MIT, and is still used for hardware hackers as well as software.

That's not to say that an additional term is not desirable, merely that "hacker" coveres the people in both worlds that have the appropropriate skill and nature.

There are those who claim Leonardo da Vinci as a hacker, you know. :)
jonored, you bumped a neuron! Yes, MIT claims the term hacker... It was the guys in the after hours model train club who admired someone who could hack hardware intended for one perpose into something quite different, for their own on campus automated model train system.

Psychologists now suspect our brain's memory capacity is far greater than our present lifespan. It's just the retrieval rate that slows...

I will stop typing now. ;)
Congrats Vik! Looks fantastic...
As usual Wikipedia has an entry for "hardware hacker"...

I think we're guilty. :-s
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