Method and system for machining a sculptured surface

A method for machining a sculptured surface, the method comprising the steps of:

• inputting surface data produced in accordance with a design and defining a desired sculptured surface to be produced by machining;
• confirming no interference between a sectional shape of said sculptured surface to be produced and a shape of a selected tool on an interactive screen, said sectional shape of said sculptured surface to be produced and said shape of the selected tool being displayed on said interactive screen, and employing the selected tool;
• generating a first offset surface by an inverse offset method in which an imaginary tool inverse to a sculptured surface having the required shape is moved, in terms of setting a point machining as a minimum machining unit of shape machining, setting an inverse tool shape as an offset surface for the point machining, and defining an enveloping surface of the offset surface for the point machining as an offset surface for a surface machining;
• generating a second offset surface by a correcting operation in which a Z-coordinate value of a center point of the selected tool is obtained by calculating coordinate values from a machine point on said sculptured surface having the required shape to the center point of the selected tool, said Z coordinate axis being defined along a center axis of the selected tool, the obtained Z coordinate value of the center point of the selected tool is compared with a Z coordinate value of the first offset surface, and the larger Z coordinate value is employed as the Z coordinate value for correcting said first offset surface so that the second offset surface is generated;
• generating a tool path in accordance with said second offset surface and at least one of inputted machining conditions including a cutting speed, an initial position of the selected tool and machining mode;
• and
• converting data of said tool path into numerical control information by a post processor.