TOOL PATH GENERATION FOR FREEFORM SURFACES

Abstract

Freeform surfaces now-a-days have many applications in industries like aeronautics, automobiles and their manufacturing is a challenging task for manufacturing industries. In manufacturing of these sculptured parts from prismatic stock rough machining usually constitutes most of the machining time owing to the significant difference between the stock and the part shape. In the metal cutting industry, a large amount of time is often spent on data exchange, numerical control (NC) tool path generation and NC program preparation for sculptured parts. Generally manufacturing for these sculptured parts is done on 5-axis machine due to their complexity. In the present work an approach called slicing technique is used to convert the 3D geometry (machined on 5-axis) of sculptured part to 2D geometric (machined on 2 '/2 or 3-axis) level and then a simple zig-zag path strategy is applied for each slice according to its level of details (LOD). Basically the system includes four components: - a data extraction module, a volume slicing module, a tool path module and Cutter Location (CL) file generation module. A CAD design model is usually documented in a particular data format. The geometric and topological messages may not be easily "visualized" or understood by the tool path generator (a system or a human programmer). Therefore the information needed for tool path generation has to be extracted from CAD files and converted in to usable format for generating tool paths. This is done by the data extraction module. The volume slicing module slices the freeform surface horizontally layer-by-layer to improve the machining efficiency. The reason is that planar path is more advantageous and moreover it reduces a 3D problem to series of 2D problems. The tool path module will generate the zig-zag tool path for each layer based on its level of details. This module is applied for both roughing and finishing operations. The cutter location (CL) file generation module generates a CL file which contains the co-ordinate movements of tool that is the TOOL PATH to get the final desired shape.