Friday, July 30, 2010

Gem Holders

Last year I learned to engrave little pictures onto various gemstones using a CO2 laser. I got the best results from lab-grown rubies and sapphires (both corundum) which etched to a frosty image that contrasted nicely with the saturated color of the stones.

I wanted to share the engraved gemstones with other puzzle enthusiasts but the loose stones are easily lost, so I designed and built gem holders on the SD300 using black material.

The flexible tabs allow the gem to be snapped securely into place. Each gem can be removed by pushing it out of the holder through a cavity in the back.

I also built a gem holder using transparent material, which slips into an opaque white holder.

Wednesday, July 21, 2010

Reditt model

I stumbled upon a model of a cute little robot called Reditt. I was intrigued by the thin, angular antenna atop his head. It's only about 1mm thick, but I was sure the SD300 should could build it because the antenna lies entirely within a single plane and the thick ball would prevent any loose ends.

I built the model lying down, so the antenna would be completely horizontal. Here's the completed model block with the robot's face smiling from within the support material.

I had arranged the peeling cuts so the material could be peeled away from one side of the antenna at a time.

I peeled one section at-a-time from the end of the antenna to the robot's head until the whole antenna was free.

I built a pair of robots, using amber-transparent and opaque cream plastic. The antenna looks delicate, but it's surprisingly robust. One survived unblemished after being dropped on a concrete floor.

The transparent model looks spectacular standing on a Oscillating LED Light Stand I bought from American Science and Surplus for $2.95.

Thursday, July 15, 2010

Mizzing Piece "Test Part" puzzle

The SD300 has a built-in capability to build an functional Test Part using a minimum of consumables (less than $3 of total materials) which can be folded and snapped together into a neat little pyramid. Most users probably accumulate plenty of these parts from testing the printer after cleaning, servicing, and routine operations.

I've watched friends and guests toying with these little pyramids. Often, they try to stack them to form a larger pyramid, but it just doesn't work.

It occurred to me to design a simple part that can be combined with the test parts to build a larger pyramid, like the one pictured below. It's sort of like a "missing piece" for the larger pyramid.

In fact, my extra piece looks just like the standard test first glance. It's foldable sheet of four triangles, like the test part, but the edges are chamfered at different angles and there are other differences.

This shape forms very-narrow channels during printing, which has the disadvantage of leaving hair-thin strands of support material that must be peeled away. I've successfully cleared the waste material from every part I built so far, but it takes a bit more effort than usual!

I added a triangular hole to the new part to help distinguish it from the ordinary test parts. As shown here, it doesn't quite fold like the regular test part.

I soon found the hole was a convenient feature to help disassemble the parts, so I designed a version of the standard SD300 Test Part with a round hole to reach inside and pop it apart. A complete puzzle set consists of one Mizzing Piece part (triangular hole, at right) and five standard test parts or my equivalent (round holes, at left).

I posted the Mizzing Piece STL at Thingiverse