Automatic tool path generation for parametric surfaces in terms of Bezier patches

Abstract EN

The objective aim of this paper is to develop an algorithm that generate NC tool path for parametric surfaces based on the accuracy of a desired surface.

A designed surface is represented by sufficient control points, using these control points, the surface has been represented depending on Bezier technique to generate reliable and near-optimal tool path as well as cutter location data file for post-processing ; the proposed algorithm include two functions : •Forward step function that determine the maximum distance between cutter contact points (CC) with the given surface tolerance.

•Side step function which determine the maximum distance between two adjacent tool paths with a given scallop height.

The output of these two functions are engaged with the generated interior data of the desired surface and feed automatically to a vertical CNC machine (Bridge Port) through the serial port (RS232), then one tool paths has been implemented for manufacturing one parametric surface, with tolerance of 0.5mm, using vertical CNC milling machines (Bridge Port) with ball nose end mill cutter ∅14mm.

The proposed algorithm has been implemented for tool path generation of several parametric surfaces to illustrate its flexibility,