Automatic machining using constructive solid geometry with Boolean combinations of primitives including tool offsets to form a machining pattern

The method of machining 3-dimensional solid parts with a rotating cutting tool comprising the steps of:

• providing a constructive solid geometric description of a desired part expressed as a Boolean combination of primitives and the result of applying a series of set operations;
• determining offset primitives by offsetting every primitive by the radius of said cutting tool;
• creating a description of an offset part by applying to said offset primitives the same series of set operations;
• taking planar section slices of said offset part and obtaining section curves which are the intersections of slicing planes with said offset part and describe the paths followed by the center of said cutting tool;
• and
• generating position commands to direct a machine tool to follow said curves to automatically cut the desired part.

The method of machining 3-dimensional solid parts with a rotating cutting tool comprising the steps of:

• providing a constructive solid geometric description of a desired part expressed as a Boolean combination of primitives and the result of applying a series of set operations;
• determining offset primitives by offsetting every primitive by the radius of said cutting tool;
• creating a description of an offset part by applying to said offset primitives the same series of set operations;
• taking planar section slices of said offset part and obtaining section curves which are the intersections of slicing planes with said offset part and describe the paths followed by the center of said cutting tool to make finish cuts;
• offsetting every such section curve in its respective slicing plane to obtain paths followed by said cutting tool to make rough cuts;
• and
• generating position commands to direct a machine tool to follow said curves to automatically make rough and finish cuts and machine the desired part.

The method of machining 3-dimensional solid parts with a ball end cutter comprising the steps of:

• providing a constructive solid geometric description of a desired part expressed as a Boolean combination of primitives which is the result of applying an ordered series of Boolean set operations, including union, intersection and subtraction, to said primitives;
• determining offset primitives by offsetting primitives which are united or intersected by a positive radius equal to that of said ball end cutter and those which are subtracted by a negative radius;
• creating a description of an offset part by applying the aforementioned series of Boolean set operations to said offset primitives;
• taking planar section slices of said offset part and obtaining section curves which are the intersections of slicing planes with said offset part and describe the paths followed by the center of said ball end cutter to make a finish cut;
• and
• generating numerical control machine code to direct said ball end cutter to follow said paths, and machining the desired part.