NC tool path synthesis.

摘要

Milling and grinding are the manufacturing operations considered in this thesis for fabricating geometrically complex parts (e.g. molds and dies). Numerically controlled (NC) machine tools have provided the metal working industry with an efficient (quick and accurate) method to manufacture molds and dies. The efficiency, however, is realized only when the manufacturing data is accurate. Tool path generation, an important component of the manufacturing data generation, is the focus of this thesis.; Specifically, in this thesis, efficient and robust techniques are developed for maximizing the material removal rate and improving the surface finish in milling and grinding operations. The contributions of this thesis are: (a) a thorough study of the geometry of the cutting tool relative to the designed part, (b) a representation of the manufactured part based on scallop height functions, (c) a local method for approximating the tool path spacing based on differential geometry and (d) a technique for controlling the local and global geometry of the tool paths based on the scallop height functions. In addition to giving the user a direct control of the surface finish, the tool paths generated using the above are efficient with respect to practical metrics such as tool path length, curvature, number of tool retractions, etc. Our method has been implemented and tested on several parts resulting in approximately a 20-30% reduction in machining time.; Currently, most commercial and research systems for NC tool path adopt a "generate and verify" approach which is iterative and time consuming. Our tool path generation is a step towards realizing a "generate only" approach.