A novel iso-scallop tool-path generation for efficient five-axis machining of free-form surfaces

Abstract

Tool-path generation is the most important factor in effective machining. A novel iso-scallop tool-path generation strategy was developed for the efficient five-axis machining of free-form surfaces. In the developed iso-scallop method, the cutter paths were scheduled so that the scallop height formed between two adjacent machining paths was constant. The tool orientations along the tool-paths are optimized to maximize material removal and to avoid local gouging. For this aim, the effective cutter radius was adjusted to the surface curvature and then side step was calculated for a constant scallop height. An effective binary searching algorithm was proposed for side step and step length determination. A surface curvature analysis procedure was applied to the entire surface for determination of the minimum radius of curvatures along the feed and side-step directions. Additionally, a feasible flat-ball-end tool selection method is presented by using the concave radius of curvatures which are calculated by surface curvature analysis procedure. Local and rear gouging was analyzed for all cutter contact points. Based on the results, the iso-scallop method reduced the total path length by about 22-50%. Three-dimensional (3D) free-form surfaces were delineated with the STEP-AP214 format, and the "B-spline-surface-with-knots" entity was used to define the B-spline surface geometry. Windows®-based software written in Borland® Delphi has been developed according to the algorithm presented. © 2010 Springer-Verlag London Limited.