I just recently built my Printrbot Junior v2 3D printer and have been printing test pieces in order to calibrate the printer. Now that all that is done, and after printing a filament guide to keep my feed line under control I decided it was time to design and build something.
I am attempting to build an Ironman MkIV suit for my son, and the arc reactor in the chest is one of the toy ones which light up and make a noise when you press the front. That was ok, but the lights were pathetic, so I decided to add an array of LEDs to make it brighter. This would involve extending the arc reactor by about 11mm to allow for the installation of a LED torch head (torch shown but can't source them anymore), and a transparent plate made from a CD packing disk. This would allow the original lights to illuminate the reactor when the power to the main LEDs was removed.
So I designed a ring which fitted inside the top and covered the bottom with extension posts for the screws. In the top I added pins to locate in the existing screw holes in the top, and put screw holes in the bottom of the posts for the existing screws. The design was done in Lightwave modeller v8.5 and exported as an STL file. Repetier host flagged some issues with the designed file, so I ran it through the online STL checker at http://www.netfabb.com which fixed the problems. I then printed the file in PLA. I wanted to use ABS plastic which is stronger and not so likely to degrade in sunlight, but I have been having so much trouble getting it to print well that I decided to use the PLA and paint it.
As you can see, one of the locating pin holes was missed in the 3D print. For some reason when Slic3r sliced the object it filled in the top of the post, but not the bottom where the hole printed fine. But that's ok, I can drill it out.
The extension fitted perfectly in the top, and with just a bit of sanding on the inside of the bottom of the extension to remove some artefacts and ridges from the printing process, it fitted over the base and the posts seated perfectly with holes lined up with the screw holes.
So there it is, comments, questions and criticism welcome.