Original Date: 11/03/1996
Revision Date: 01/18/2007

Traditional machining methods to machine complex blend surfaces and free-form surfaces have typically employed the use of a ball end mill to achieve the final geometric surface configuration. However, ball end mills have limited performance characteristics such as allowable depth of cut, feed rates, and step-over distances. The Oak Ridge Y-12 Plant was challenged to improve cutting times and final machined surface finishes for a series of jobs with complex surfaces.

Y-12 incorporated the use of non-spherical (toroidal) cutters to greatly enhance the cutting speeds and depths of cut, achieving improved surface finishes and extending tool life. Due to the geometric composition of the torus cutter, the tool cannot be presented perpendicular (normal) to the surface of the part but must be presented with a positive lead angle referred to as the non-spherical lead angle. Through the use of CAM software, Y-12 NC programmers have been able to develop variable lead angles by creating and adjusting vector meshes to the desired lead angle to optimize the metal removal rates. Y-12's experience with this innovative machining technique has indicated a starting lead angle of 45° and reduced down to 5-10° for optimum performance. Through the innovative use of these cutters and NC program modification and optimization for complex surfaces, Y-12 estimated savings of over $450,000 for one job.

For more information see the Point of Contact for this survey.