Finished product first:
I've recently started mining Gridcoin and while reading about Gridcoin came across steemit. One of the pages I read was jeffpatat's 3D printed Gridcoin (https://steemit.com/utopian-io/@jefpatat/the-3d-printed-gridcoin-chip-is-finished-and-it-looks-great). I liked Jeff's idea and decided to try to design and print my own. I think jeffpatat's looks great, but I wanted to make a version that matched the Gridcoin logo.
First I created the 3D model using Autodesk Fusion 360. I designed it to match a standard poker chip, so it is 39 mm wide and 3.4 mm thick. It was also designed so the Gridcoin logo will display correctly on both sides of the chip. You can see a render of the current version below. 
When the design was finished I exported it to 3 different STL objects:
- The White
- The Purple
- The Clear
The clear STL's are 0.2 mm thick full coverage hexagons used to give the top and bottom of the final printed coin a uniform smooth surface.
Once the 3 STL files were exported I used Simplify3D to assign the STL's to different extruders and slice the object to create a gcode file. My 3D printer uses a diamond hot end (http://reprap.org/wiki/Diamond_Hotend) so it can print up to 3 different filaments. After slicing with Simplify 3D I ran the output GCode file through a custom program I'm working on to make the file work better with the Diamond hot end.
After I had my final GCode, I sent it to my printer and this was the result!
Front:
Back:
If you have any suggestions, let me know! I've only printed one so far, but plan to print more. I may even try switching the purple color to a different color to be used for different denominations of poker chips.
I've uploaded the STL files to print your own here: https://www.thingiverse.com/thing:2655722