Monday, September 03, 2007
Fruit of My Labor (Day Weekend)
The majority of my work was focused on this awesome instructable that has caught the eye of the forum members. It is a nice, simple design, and immediately caught my eye because it was obviously something that is simple enough for someone with basic woodworking skills could construct. It also lends itself very well to lasercutting, which makes it even more accessible to people who dont possess such skills. Finally, it appears to be a successful design, as he used it to actually mill plastic, foam, and PCB's. I emailed the creator, Tom McGuire, and he seemed very interested in collaborating with RepRap, or at least letting us use his design.
Upon hearing that good news, I sat down to draw out the machine in QCad. My CAD skills were a bit rusty. Other than Kicad, the last time I used any CAD programs was the 3 years I took in high school. I really enjoyed it then, and all the stuff I learned started coming back to me. I didn't have any measurements to go on, so I was going off what I could gather from the pictures, and my previous knowledge from trying various other approaches to building a cartesian machine. It was tough, and there were a few false starts, but I think it turned out all right.
All of the files are in the RepRap Subversion, and I've even gone as far to create a page on the RepRap wiki that has a TODO, basic information, and the skeleton of a HOWTO page. As I progress, I plan on documenting that area more and more.
Please check out the designs, view the video, and give me any feedback you come up with. Once I do some final tweaks to the design, I'm going to do a test-run with sticker templates and cardboard. If that looks fine, then I'm going to go ahead and do a one-off lasercut order. If that turns out well, and I end up with a working machine, then I'll definitely be looking into doing a bulk order. Thats probably a month or two off, but with your help, I think we can get this design to the point where it can serve as a good solution to the chicken/egg problem that we've been dealing with for a while.
Read more on the main wiki page for the design.
Just a precision: If i get it right from the drawings, the cylindrical positioning stage will be on top of the x-y plane?
Doesn't this mean that this device will not be able to translate the rotation axis anywhere on that plane with the extruder just above it, producing only concentric features around the extruder position? Well it could probably also do other cicular features away from this point, combining cartesian and cylindrical movements but there could not be a number of cylindrical features (like drill holes) in any point of the surface, made by simply rotating the xy plane.
A way to achieve this would be if the x plane would be mounted on top of the disk, thus allowing the plane to move over the disk rotation axis. The y axis should be on the extruder arm, to allow to create different radii... err.. well maybe i'm complicating that very elegant design to much now :)
i deviated from that design slightly, by replacing the bottom pipes with a flat, board.
its completely cartesian X/Y/Z axes. the x sits on the base, and the y sits on the x. it uses gas pipe to elevate and rotate the Z stage 90 degress.
the flat parts of the design are intended to be made from 1/4" acrylic. by woodworking skills, i simply meant the ability to drill and cut soft materials.
if you add in the printable templates that are possible with this design, you only have to worry about positioning your drill properly, and not measuring properly as well... the printer takes care of that.
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