Today I had my first success CNC machining based on an STL file. I used Meshcam to generate the tool path and Mach3 to control my home-made 3 axis milling machine. The first 3D mesh that I printed was the same version of my face that I previously 3D printed. As usual, none of my family members lets me scan them, so I am usually working with my own face. Here is the final result from today. This took about 3.5 hours to machine. There was one tool change from a 0.125″ bit (for roughing) to a 0.100″ bit (for finishing).
Here is a Blender rendering of the STL file that I used to perform the CNC machining.
I added a large counterweight to the Z axis to balance out the lever arm of the heavy spindle. This really worked better than I expected. Since the mill uses Nema 23 motors, it has no problem lifting the spindle plus counter weight, which I think together weighs about 16 pounds. The machine moved without any problem at all. I also adjusted the acceleration in Mach3 so that no abrupt movements caused the heavy spindle and counterweight to jiggle around at all. Here is a picture of the mill. You can see the large, brass counterweight in the background.
Here are some videos of the machine in action. Most are narrated.