Abstract: An apparatus for cutting any one of blocks and panels of cellular plastics into various shapes. The cellular plastic is held on a stationary platform around which a movable frame is affixed to two slides. The movable frame moves on two horizontal rails to effect cutting in the x-direction. Cutting is done with a hot wire affixed to two slides which move together vertically on vertical rails along the moveable frame to effect cutting in the y-direction. Stepping motors are driven by a computer to provide for displacement of the hot wire. Each motor includes a pinion which is mounted on a shaft directly engaging gear-racks parallel to the rails, to effect cutting of various shapes defined by the equation y=f(x).