Rapid Planning for CNC Milling Approach for Rapid Prototyping

This paper presents a description of how CNC milling can be used to rapidly machine a variety of parts with minimal human intervention for process planning. The methodology presented uses a layer-based approach (like traditional rapid prototyping) for the rapid, semi-automatic machining of common manufactured part geometries in a variety of materials. Parts are machined using a plurality of 21⁄2-D toolpaths from orientations about a rotary axis. Process parameters such as the number of orientations, tool containment boundaries, and tool geometry are derived from CAD slice data. In addition, automated fixturing is accomplished through the use of sacrificial support structures added to the CAD geometry.The paper begins by describing the machining methodology and then presents a number of critical issues needed to make the process automatic and efficient. Example parts machined using this methodology are then presented and discussed.