Five-axis machining of STL surfaces by adaptive curvilinear toolpaths

Abstract

We propose a new framework for toolpath generation for five-axis machining of part surfaces represented by the StereoLithography (STL) format. The framework is based on flattening the STL part and generation of adaptive curvilinear toolpaths. The corresponding cost functions, designed to represent the accuracy and the efficiency of the toolpath, are scalar functions, such as the curvature, kinematic error, rotation angles, machining strip or material removal rate or a vector field when the tool moves along a curvilinear path partly or even entirely aligned with directions considered to be optimal. The adaptive toolpath exploits grid generation methods and biased space-filling curves, combined with adaptation to the boundary and the domain decomposition. The proposed methodology of the adaptive curvilinear toolpath (ACT) has been tested on a variety of STL surfaces, including a case study of STL dental parts. Machining crowns/ implants for four basic types of human teeth, molar, premolar, canine and incisor, has been considered and analysed. The reference methods are the standard iso-parametric path, MasterCam toolpath, and advanced methods of NX9 (former UG). The experiments show that there is no universal sequence of steps applicable to every surface. However, a correct choice of the tools available within the proposed ACT-framework always leads to a substantial improvement of the toolpath, in terms of its length and the machining time.

Length-optimal tool path planning for freeform surfaces with preferred feed directions

“…Clearly, increasing each w i can decrease the overall path length i d i . This line of research was pioneered by Chiou and Lee [3] and improved in a series of papers [16][17][18][19][20]. Basically, they sought to align tool paths with a preferred feed direction field of maximum strip width.…”

Study of the tool path generation method for an ultra-precision spherical complex surface based on a five-axis machine tool

“…Software for generating complex curved tool paths is widely used, and popular programs include UG [31][32][33], PRO/E [34], and PowerMILL [35]. The main advantage of commercial software is that it can automatically generate tool paths flexibly according to the shape of a rough workpiece and a machining target.…”