Jonathan Ward from the MIT Center for Bits and Atoms has designed a snap-together, desktop-sized CNC milling machine. The MTM Snap (part of the Machines that Make project) is made from 1/2-inch high-density polyethylene (HDPE) – itself milled on a ShopBot – and can be assembled for about $700. This three-axis CNC machine can mill circuit boards, wax molds, and harder materials in a 5x3x1.75″ working area.
The MTM Snap is controlled by an Arduino board running grbl, a full-featured and robust g-code interpreter. A custom shield (designed by Nadya Peek) with three Allegro A3982 chips drives the machine’s stepper motors, and the whole thing is controlled from a simple GUI written in Processing. The advantage of this setup is that you can use the machine from pretty much any computer: desktop or laptop, Mac, Windows, or Linux. We use the CBA’s Kokompe tools for generating g-code files, but grbl should handle most files from other sources (like PCB-GCode).