An improved calculation method for cutting contact point and tool orientation analysis according to the CC points

Abstract Tool path generation is an important step of five-axis NC milling which plays an important role in parametric surfaces and free-form surfaces manufacturing. Cutter contacting (CC) point calculation is considered as a basic procedure of tool path generation. The step lengths formed by cutter contacting points have an effect on the chord error along feed direction. In traditional calculation method for CC point discretization, the segments connected by adjacent CC points distribute on both sides of the theoretical tool path curve. This situation magnifies the cutting error to some extent and enlarges the expected margin if the surface demands polishing or grinding. Aiming at this issue, this paper proposes an improved constant chord error method for CC point calculation. In the proposed method, the CC points lay on the theoretical tool path curve when the tool path curve is concave and lay on the chord error offset curve when is convex, which ensures the segments connected by the adjacent CC points distribute on one side of design surface, the side of the scallop height between tool paths. Therefore, the actual margin of polishing or grinding can be reduced. The influence of inflection points is also considered in this method to avoid accuracy deterioration caused by the long steps occurring near the inflection points. In part processing, local gouging and global collision must be avoided in tool orientation determination. This paper analyzes tool orientations with no rear gouging and no collision based on the calculated CC points. The novel discretization method for CC points is calculated on a single blade model, and the tool orientations are generated on an open integral impeller. A DMG DMU50 machine tool and a Hexagon three coordinates measuring machine are applied for experiments and measurements. The results show that, the CC point discretization method proposed in this paper offers many advantages over the traditional constant chord error method and commercial software, such as quantity of points, curve fitting, no overcut, and residual margin distributing. At last, blade and tunnel of the open integral impeller with safety tool orientation is machined and verified on the DMG DMU50 machine tool.

[1]  Jing-Rong Li,et al.  Contour parallel tool path planning based on conformal parameterisation utilising mapping stretch factors , 2019, Int. J. Prod. Res..

[2]  Keigo Takasugi,et al.  Parameter-based spiral tool path generation for free-form surface machining , 2018 .

[3]  Hsi-Yung Feng,et al.  Iso-planar piecewise linear NC tool path generation from discrete measured data points , 2004, Comput. Aided Des..

[4]  Hon-Yuen Tam,et al.  Iso-planar interpolation for the machining of implicit surfaces , 2002, Comput. Aided Des..

[5]  Bailin Deng,et al.  Iso-level tool path planning for free-form surfaces , 2014, Comput. Aided Des..

[6]  Kai Tang,et al.  Collision-free tool orientation optimization in five-axis machining of bladed disk , 2015, J. Comput. Des. Eng..

[7]  Wang Haixia,et al.  Iso-parametric tool path generation from triangular meshes for free-form surface machining , 2006 .

[8]  Aun-Neow Poo,et al.  The implementation of adaptive isoplanar tool path generation for the machining of free-form surfaces , 2005 .

[9]  Ming Lei,et al.  Iso-parametric CNC tool path optimization based on adaptive grid generation , 2009 .

[10]  Zhao Shi-tian,et al.  Algorithm of variable forward step size planning in freeform surface machining , 2009, 2009 International Conference on Information and Automation.

[11]  Aun Neow Poo,et al.  Adaptive iso-planar tool path generation for machining of free-form surfaces , 2003, Comput. Aided Des..

[12]  Ke Xu,et al.  Region based five-axis tool path generation for freeform surface machining via image representation , 2019 .

[13]  Ahmet Can,et al.  A novel iso-scallop tool-path generation for efficient five-axis machining of free-form surfaces , 2010 .

[14]  Hongbo Li,et al.  Power Series Solution for Isoscallop Tool Path Generation on Free-form Surface with Ball-end Cutter , 2012, Math. Comput. Sci..

[15]  Qiang Zou,et al.  Iso-parametric tool-path planning for point clouds , 2013, Comput. Aided Des..

[16]  Christophe Tournier,et al.  Iso-scallop tool path generation in 5-axis milling , 2005 .

[17]  L. Tunc.  Smart tool path generation for 5-axis ball-end milling of sculptured surfaces using process models , 2019, Robotics and Computer-Integrated Manufacturing.

[18]  Hsi-Yung Feng,et al.  An improved tool path discretization method for five-axis sculptured surface machining , 2007 .

[19]  Hsi-Yung Feng,et al.  Preferred feed direction field: A new tool path generation method for efficient sculptured surface machining , 2015, Comput. Aided Des..

[20]  Kai Tang,et al.  Efficiency-optimal iso-planar tool path generation for five-axis finishing machining of freeform surfaces , 2017, Comput. Aided Des..

[21]  Lutfi Taner Tunc,et al.  Process simulation integrated tool axis selection for 5-axis tool path generation , 2016 .

[22]  Christophe Tournier,et al.  5-axis Iso-scallop Tool Paths along Parallel Planes , 2008 .

[23]  Jianrong Tan,et al.  Non-redundant tool trajectory generation for surface finish machining based on geodesic curvature matching , 2012 .

[24]  Zhiwei Lin,et al.  A generic uniform scallop tool path generation method for five-axis machining of freeform surface , 2014, Comput. Aided Des..

[25]  Krishnan Suresh,et al.  Constant Scallop-height Machining of Free-form Surfaces , 1994 .

[26]  Jianzhong Fu,et al.  An accurate surface error optimization for five-axis machining of freeform surfaces , 2014, The International Journal of Advanced Manufacturing Technology.

[27]  Pengcheng Hu,et al.  Five-axis finishing tool path generation for a mesh blade based on linear morphing cone , 2015, J. Comput. Des. Eng..

[28]  Qiang Zou,et al.  Tool path planning based on conformal parameterization for meshes , 2015 .