Here is a custom stamp I did for Beecher’s Magazine at the University of Kansas.
This was created from a jpeg file.
I used Inkscape to do the tracing of the image. I saved this file as a dxf autocad file. After I had an outine, I extruded with Openscad to 1 centimeter. After I did that I exported the 3d image (stl file) into Sketchup. I have added plugins into Sketchup. I am using STL Importer by Jim Foltz and Export to DXF or STL plugins in Sketchup. Then I reversed the 3d model and added a base. Then I exported the file as an STL file.
After I have an STL file is is very easy to get a gcode for the printer. I use skeinforge to do the slicing of the model. I printed this one using 20% fill. This was printed with a Solidoodle 2 printer using 1.75mm yellow fluorescent ABS.
The results turned out well. I did a little trim where the B doesn’t connect with the gun with a Dremel 3000 with a thin cut off wheel. I plan on coating the bottom with either rubber tool coating or liquid electrical tape to give it a more stamplike feel.