Finding Feasible Tool-Approach Directions for Sculptured Surface Manufacture

Abstract

Determining tool-approach directions is an important issue when an effort is made to transfer CAD data into manufacturing automatically. An algorithm is developed to determine whether a given part can be machined on a three-axis milling machine. In the algorithm, a sculptured surface is first approximated with smaller subpatches by an adaptive subdivision method. For the unit normal vector to each subpatch, a hemisphere is then defined. Any point on the hemisphere defines a feasible tool-approach direction for the corresponding subpatch. The intersection of the hemispheres for the sculptured surface is a polyhedron. A set of points on the polyhedron is the set of feasible tool-approach directions for the sculptured surface. If a set of feasible tool-approach directions exists for a sculptured surface, the NC tool paths and G-codes for machining the surface on a three-axis milling machine can be generated automatically by an NC tool-path generation algorithm. The algorithm can be used for orientation and fixturing of the workpiece for interference free machining. The algorithm for finding feasible tool-approach directions is implemented in C running on a Sun engineering workstation as a module in an integrated sculptured surface design and manufacturing (ISSDM) system.

Additional information

Notes on contributors

Kwangsoo Kim

Kwangsoo Kim is an Associate Professor in the Department of Industrial Engineering at Pohang University of Science and Technology. His research interest is in the area of CAD/CAM. His current research activities include feature-based surface modeling, feature-based solid modeling, knowledge-based geometric constraint solving, feature-based NC machining, assembly modeling, and intelligent CAD.

Jaehun Jeong

Jaehun Jeong received his MS in Industrial Engineering at the Pohang University of Science and Technology, South Korea, in 1994, where he is currently a Ph.D. candidate. His research interests include curve-offsetting, feature-based surface modeling and feature-based surface machining.