CNC machining is a subtractive process were material is cut away from existing stock to create objetcs.  Fused deposition modeling  (FDM), 3-d printing and stereolithography are additive processes where material is built up in layers to create objects. After the parts were “printed”  they  were then assembled.  No extra material was used. This was an experiment where we converted a CNC machine into a 3-d printer. First, a yoke was made to sleeve the router and hold plastic containers filled with an A-B  Polyurethane Foam mixture.  As the  cnc program ran, a valve was released which enabled the a-b compound to flow along the lines of the toolpath.  Once mixed the foam expanded to create the part.