Automatically optimized NC tool path generation for machining

A method of generating optimized tool paths for milling molds and dies with a cutting tool comprising:

• providing a three-dimensional solid model of a part cavity and of-any containment and avoidance regions to which milling is respectively restricted and is prohibited, and forming a milling region by intersecting said cavity and any containment region and subtracting therefrom any avoidance region;
• taking a planar section through said milling region and obtaining a closed curve which describes boundaries of said milling region and has a plurality of loops oriented such that material to be cut is on the left;
• deriving a first inset curve at a given distance from said closed curve each loop of which is a finishing tool path across which said tool cannot move without gouging and each starting a nest of tool paths, and numbering every finishing tool path in sequence;
• repeatedly generating other inset curves at a constant distance from a previous inset curve each loop of which is a roughing tool path and is a member of one nest or starts a new nest, numbering said roughing tool paths in sequence such that the innermost path has the highest number, and stopping when a last inset curve has no arcs;
• ordering said roughing tool paths in an optimized sequence to mill said cavity so as to follow a prechosen set of ordering guidelines while minimizing the number of retractions of said tool to mill a next tool path, outputting a list of said tool paths in the order to be milled separated by a retraction indication, and generating straight line tool motion paths to move to the next tool path;
• and
• augmenting said finishing tool paths with tangential approach and finish arcs.