Automatic Tool Path Generation for Parametric Surfaces in Terms of Bezier Patches

Abstract

The objective aim of this paper is to develop an algorithm that generate NC toolpath for parametric surfaces based on the accuracy of a desired surface. A designedsurface is represented by sufficient control points , using these control points , thesurface has been represented depending on Bezier technique to generate reliable andnear-optimal tool path as well as cutter location data file for post-processing; theproposed algorithm include two functions:· Forward step function that determine the maximum distance between cuttercontact points (CC) with the given surface tolerance.· Side step function which determine the maximum distance between twoadjacent tool paths with a given scallop height.The output of these two functions are engaged with the generated interior data of thedesired surface and feed automatically to a vertical CNC machine (Bridge Port) throughthe serial port (RS232), then one tool paths has been implemented for manufacturing oneparametric surface, with tolerance of 0.5mm, using vertical CNC milling machines(Bridge Port) with ball nose end mill cutter ø 14mm.The proposed algorithm has been implemented for tool path generation of severalparametric surfaces to illustrate its flexibility,

Keywords

• parametric surfaces
• bezier patches
• tool path generation
• forward step
• side step
• scallop height