Toolpath generation and verification for optimal machining of sculptured surface

Abstract

This thesis suggests a new methods for the generation of the toolpath and the verification of the NC code. To generate toolpath for rough cutting, the offset surface is generated from the Z-map. To generate the offset surface from Z-map, the triangular faces are used. After obtaining the offset surface, comparing the offset surface and the height of rough machining area determines the rough machining area. This thesis uses three inclination angles (x-axis parallel, y-axis parallel, major- axis parallel ) and three machining methods (one-way milling, zigzag milling, hybrid milling) to evaluate the toolpath for rough cutting. The objective function is proposed to select the optimal toolpath. Since the tool life in down-milling and up-milling is considerably different from each other, tool life is considered separately in the objective function. When 9 candidate toolpath patterns are given, the most effective toolpath for rough cutting is selected by using the objective function. In this research, the bi-arc interpolation is used to improve surface roughness and productivity. Using the by-arc interpolation, the workpiece can be produced by circular interpolation only. The surface roughness of bi-arc interpolation is better than that of linear interpolation. This paper describes the geometric verification as well as manual & automatic editing. The new method is proposed to quickly find out and easily edit the errors. The verification system developed in this research displays the texts of the NC code and the graphics of toolpath at the same time. Furthermore, in the case that it is impossible to verify the toolpath by the manual editing, the verification system presents the automatic editing. In the automatic editing, the NC codes causing the overact are updated first, and then NC codes for undercut are regenerated. This study represents the non-dimensional cutting force model. With non-dimensional cutting force model it is possible to estimate efficiently the...