The paper presents a model of tool with controlled geometry of the active surface. This tool is very suitable for use with an industrial robot, for example, to form polystyrene foam. The tool was built in the form of two discs mounted on axes stepper motors positioned in the frame. This discs combined using two wires with feature a length of a wire compensation system. It was made using the spiral spring. Tool geometry was set by rotating one of the discs at a specific angle (0-180o). After starting the both engines, concurrently at the same direction, surface of tool action is obtained in the form of hyperboloid. To run the tool uses stepper motors connected to a computer equipped with an interface card and specially developed control software. Tool joined to the IRb60 robot wrist can obtain curved surface as a superposition of the kinematics of tool and robot wrist.