Monday, April 18, 2011

Trammel of Archimedes



I haven't been feeling very creative this week, so I downloaded the Trammel of Archimedes model just to build something interesting.

As I've done on many occasions I wanted to build a two-color model, but I tried a new approach: I remotely monitored the log by putting the SDM_Printers folder on my network. That enabled me to pause the printer just before the model reached a height of 24.3mm (which shows as 24300 microns in the log).


While peeling away the support material I found a weak spot in a thin wall, probably caused by a bad weld. I applied a drop of Weld-On 2007, which repaired the weak spot by causing the PVC to bond to itself without adding any glue or filler, so it wouldn't affect the dimensions.


The cleaned parts take full advantage of the contrasting colors.


Here's a quick video showing how the Trammel of Archimedes traces an ellipse.

video

Sunday, April 10, 2011

Traffic cones with light pipe


I've been watching for an opportunity use the SD300's ability to embed light-pipe-like transparency in a model, so I decided to adapt a Traffic Cone model I stumbled upon at Thingiverse.

I built the models upside-down, with a few layers of red followed by several millimeters of transparent layers to form a window between the interior cavity and the outside walls.


As usual with hollow models I chose to clean the leftover material out of the cavities before I removed the exterior supports. That makes it simple to hold onto the models because they're still embedded in the model block.


When the exterior support material was partly cleared I tested the light-pipe effect by shining a flashlight up through the bottom of one of the models. Light shone brightly through the transparent layers!


Here's a quick clip showing how it looks on an animated light table, illuminated from below. There's probably enough volume to fit an LED and button cell battery entirely within each model.
video

Sunday, April 3, 2011

Some ball-shaped toy variations



A puzzle-making colleague requested a variation of my 2x2x1 design cut down to its bare core so it could be used as a foundation for other puzzles. I'm not sure what he wants to use it for, but I built a sample.


I'd designed it with flat spots on the top and bottom, but otherwise it formed a smooth ball when assembled. It's hard to grab onto and it would probably be difficult to attach anything to it due to the smooth surface.


Coincidentally another friend suggested another variation with thin projections. I didn't build it exactly as he'd described, but it gave me the idea of adding a rim around the equator for grip.


The rimmed version is easy to operate. It's not a real puzzle, but it would be an acceptable desktop toy.
video