Monday, January 30, 2006


RepRap at LCA2006

I had the pleasure of attending LinuxConf Australasia 2006 last week, thanks to the University of Otago, New Zealand and the sponsorship of IBM and HP. I was there as a presenter of a submission on RepRap, which is now on our documentation page. I am pleased to announce that everything was a resounding success, to the point where the presentation was voted "Best Of" and I had to do it again!

Everything worked very well indeed after a bit of run-around trying to
sort out clamp stands, hotplates, close-up cameras and so forth.

I have assembled the linear stage, and with the exception of the linkage
(redesign in progress) it works well. I have reduced the component count
to 42 components (every nut, bolt and washer) of which 5 are FDM'd and
no component modification is required other than cutting to length. I
need to taper a recess, add limit switch mountings, reduce the volume of
plastic needed and then I'll try a Mk 2. The axes will stack to
make an X-Y table. If Simon can get code to drive 2 steppers off one
PIC, it'll make for a very tight little unit.

Fortunately Suz came to the conference shortly after me, armed with a box of goodies from the Stratasys. I Assembled the Mk 1 stage from the parts that night, with no modification needed that one couldn't do without a penknife. Here is the beast:

The star-shaped holes allow standard bolts to be used as accurate
self-tappers (saving on nuts), and grip smooth shafts well. They should
allow us to eliminate some of the clamps and their attendant nuts &
bolts - also some of the more ungainly support material.

The presentation itself went flawlessly, with the TIP-based extruder
extruding nicely in front of the close-up camera. For a Polymorph demo,
I turned a hard Polymorph pancake into an amorphous mass, then into an
apple-piercing dagger. Wood's metal was demonstrated by casting shapes
in nothing stronger than filter paper.

After the presentation I was swamped by a rush of geeks, wielding
cameras and wanting to know if it was OK to photograph the mechanism :)
I actually ended up on national TV, but sadly the RepRap was not
mentioned. Linux was a hard enough concept for the news team to get
their heads around.

I spoke to MIT's Jim Gettys of the One Laptop Per Child project, who is
sympathetic to our cause but has other problems to deal with right now.
The good news for us is that he plans to release a "Hacker" version of
the OLPC which comes without case and with access to built-in ports that
the OLPC is not otherwise interested in.

I also spoke to Dr Wayne Piekarski from the the University of South
Australia who is well-known for his work on virtual and augmented
reality systems. Some of his students are developing a CAD/CAM system
and would like to get hold of one of our extrusion heads for it. Wayne
got a "Best Of" slot last year.

In all an extremely satisfying and totally knackering week.

Vik :v)

"Some of his students are developing a CAD/CAM system and would like to get hold of one of our extrusion heads for it."

Congrats on the presentation. However, with regard to the above comment, it sounds odd that they of all people, with access to so many resources, would be asking to get hold of your extrusion head. I hope what you mean is that they intend to fabricate one of their own devices from the information provided. That is what you meant, right? Seems like such an excellent opportunity to get feedback that I hope I'm misreading this.
I've had a few chats with Wayne. I think he feels that he generally deals with making virtual objects and real worlds interact, but that creating a real object virtually would be a natural extension of his project.

I'm not sure if his establishment has access to FDM machining or not, so I couldn't really comment further.

Vik :v)
"Some of his students are developing a CAD/CAM system and would like to get hold of one of our extrusion heads for it."

Mark 2 represents, as best as I've been able to find, a major advance in the state of the art. It doesn't surprise me at all that they want to get their hands on one. :-)
Somebody should tell Wayne this has already happened and is actually where my efforts have been concentrated.

I'm working on the business aspects of it as we speak.
Perhaps you'd like to share your work with the assembled folks? There might be some aspects of your design that can be used to improve RepRap.

Vik :v)
My original effort was last May and I blogged about it here:

The goal there was to show how even a videostream can be ripped and turned into something manufacturable.

Since then I've been working on and off getting data from the virtual space Second Life directly into Pro/E (not ripped and converted). If I devoted more time to it I'd probably be done by now, but I've been getting an education in a few other areas in the meantime.

Quite recently the folks at Eyebeam R&D released a new videostream 3D ripper called OGLE. They've also taken the captured models, modified them, and fabricated them. You can see that here:

I've documented my efforts to use their tool on my blog. In particular, because Second Life has modeling tools within the virtual world (primitive, but satisfactory for now), the options are available for people to make simple objects, capture the 3D data, and use it. More interesting to me at this stage is what kinds of businesses can grow around virtual spaces with built-in tools. I'm finding that to be a tough nut to crack at this stage.

Also, keep an eye on Project Croquet. I believe it also has built-in 3D tools and is open source.
Your positioning stage concept finally came together for me there, Vik. That's very elegant! :-)
I've reduced the amount of plastic needed in the latest design, added microswitch mounts as well as slots for the NMEA 17 motors, and made the bearing mount more user-friendly. I've requested a test model, and if all goes well Simon should have his X-Y testbed in a couple of weeks or so.

I have a small mod to make to the vertical axis that will allow the Mk2 nozzle to dangle underneath it for those who prefer to move the head either up and down or around.

Vik :v)
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