Support the block so it cannot shift, tip, or pinch the wire mid-cut — any movement shows up as a wave in the surface. A flat table or fence that the foam registers against, plus light clamps or pins that do not crush the foam, is enough; the cutting force is almost nothing, so you are fighting drift, not thrust.
Keep the wire path clear so the gantry's home/return moves do not rake through the part. For very tall or long blocks, make sure your wire span and travel actually cover the stock, and consider cutting in stages. In https://cncfoam.com the material-block settings let you model the stock and check fit before cutting.
Keep the wire path clear so the gantry's home/return moves do not rake through the part. For very tall or long blocks, make sure your wire span and travel actually cover the stock, and consider cutting in stages. In https://cncfoam.com the material-block settings let you model the stock and check fit before cutting.