Research Of Intelligent Toolpath Strategies For Freeform Surface Machining Based On Surface Geometric Characteristics Analysis

Toolpath planning is one of the critical processes in CNC machining for freedom surface.The quality of toolpath directly affects the efficiency and accurcy of freedom surface. So howto generate a high quality and good efficiency toolpath is a important research subject.Besides, due to the lack of theoretical support to the compatibility evaluation of toolpathpatterns for freeform surface machining, the process of selecting toolpath strategy in mostCAM software still solely depends on users’ experience. So it is also critical to proposal someeffective method to quantitatively evaluate compatibility of toolpath strategies. Aiming to theproblem of intelligent toolpath strategies for freeform surface machining, the main works areshown as follows:(1) In order to improve the efficiency of traditional contour-parralel offset toolpathstrategy, a new contour toolpath strategy based on the concave and convex features of surfaceis put forward. In the new method, the freedom surface is divided into feature regions andordinary regions firstly, and contour toolpath is generated for each region using traditionalmethod independently. Toolpath for entity surface is generated by applying region-by regionstrategy.(2) Aiming at the problem of residual regions in contour-parralel offset toolpath forfreedom surfaces, a effective detecting method is proposed to identity the residue regions.And the cleaning toolpath is generated to remove residual regions.(3) The cause of toolpath redundancy with freeform surface machining is investigatedtheoretically. And a method is proposed to mathematically formulate toolpath redundancy forfreeform surfaces. Taking the mostly used iso-planar machining as an example, a simplymethod to calculate the rundundancy of toolpath is put forward. Finally, a number of cases aremade to prove the effectiveness of the proposed approach.