December 2010
Pather
I've just finished a set of improvements to the pather.
Our default pather (source "shared/pather/simplecrosshatchpather.cpp") first traces the outer and inner contours twice, so that the object looks smooth on the outside. Then it fills in the shape with straight lines, and connects the ends of these lines together as well as it can:
one level of an 11-sided psuedo-sphere
On each successive level, it switches between vertical and horizontal lines, to make the structure stronger:
the next level of the same psuedo-sphere
We also have an experimental pather (source "shared/pather/concentricloopspather.cpp") that traces concentric loops from the edge of the object inwards. I've gotten this to work quite well on convex polygons...
the same psuedo-sphere, concentric loops pather
...but it still has trouble on shapes with part of the interior excluded:
failed attempt at the crenelated top of a rook (chess piece)
My main focus has been improving our default pather. It worked pretty well on a lot of shapes, but it had problems with path width, shape deformation, etc.:
Here's the same shape after my improvements.
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Ben
Eight and Four Valve Tool
The Fab@Home now has the hardware capability to print eight or four materials in a single print without changing syringes. Thanks to the use of servos instead of snap motors, I was able to make an eight valve tool that measures only about 13.5 cm by 10 cm. Compared to the old four valve tool, the new eight valve tool has much more build space.
For those who only want four materials, I made a similar four valve tool.
We are starting to make designs for servo based electronics for the Fab@Home which will allow the use of these tools.
Attempted 4 Valve Tool
Well, I found some servos that will work for the valve tool, and I made a 4 valve tool using them. Unfortunately, it is too wide.
It can go forward and backward about as much as the single displacement tool, but it has an effective build space of about two or three centimeters across. The reason for this is that it takes up double it's width in horizontal build space (except for the width of the mounting bracket, which is already accounted for). The build space is effectively the overlap between where the leftmost syringe can go and where the rightmost syringe can go. In future tools, this fact should be remembered.
I do not plan to post this tool to the wiki, since it is so wide and I plan to make a better 4 valve tool. If anyone wants me to build this tool, however, I will happily post it and instructions on how to build it on the wiki.
I am currently working on another 4 valve tool that will not be as wide. The motors will stick out sideways instead of forward, and they will be staggered so that the motors that point in opposite directions can interlock. It should be done by the end of the year.
Future Valve Tool
Since I finished the old valve tool, I have been exploring different motor options which should make the valve tool cheaper and smaller. I found some servos which are considerably smaller than the snap motors, and I am working on a four valve tool that uses them.
Glasses Nose Pad
The nose piece on my glasses broke the other day, and then I lost the pieces. I tried just wearing my glasses without it, but that made my glasses sit crooked. Then I came up with an excellent solution: I printed myself a new nose piece.
It was originally meant to be a temporary solution, since I did not have time to try to get a new nose piece right then. I have been wearing it for several weeks now, and I still haven't gotten around to getting a new nose piece. I am not sure if I will, because the printed one is more comfortable than the original nose pad. The silicone is actually soft, as opposed to the fairly rigid original nose pad. Plus, it is so convenient to print another one when I get tired of this one I can just print another one, perhaps a clear one.