TOOL INTERFERENCE DETECTION AND AVOIDANCE BASED ON OFFSET NETS

A novel, fast algorithm is presented for the identification and remova l of inaccessible (i.e. interfering, and hence invalid) tool positions in three-axis surface machining using spherical ended ball nose cutte rs. For each cutter contact (cc-) point on the surface a corresponding cutter location (cl-) point is computed. Both sets of points form two meshes of points; one on the surface and the other as an offset net, respectively. Invalid tool positions introduce folds in the offset net , which can be removed efficiently involving only simple comparisons. The time complexity of this algorithm, which is independent of tool di ameter, is 0(m . n), where m and n are the number of rows and columns of the polyhedral mesh array. This method is applicable to a variety o f cutter geometries as well. Copyright (C) 1997 Published by Elsevier Science Ltd.