Tool deflection and geometrical error compensation by tool path modification

Abstract Accuracy of CNC machined components is affected by a combination of error sources such as tool deflection, geometrical deviations of moving axis and thermal distortions of machine tool structures. Some of these errors can be decreased by controlling the machining process and environmental parameters. However other errors like tool deflection and geometrical errors that have a big portion of total error need more sophisticated solutions. Conventional error reduction methods are considered as low efficiency and human dependent methods. Most of recently developed solutions cannot fulfill workshop needs and are limited to research papers. In the present study, machining code modification strategy has been considered as an applicable and effective solution to enhance precise machined components. Appropriate tool deflection estimation model as well as geometrical error analyzing methods have been selected and complementary algorithms for compensation of these errors have been developed. Metal cutting process has been modeled in a 3D simulation environment and implemented in force/deflection calculations. A software has been developed to generate compensated tool path NC program by tracing the initial tool path and compensating deflection/geometry deviations. The new procedure developed in the present work has been validated by machining Spline contours. The results show that using the new method, accuracy of machined features can be improved by about 8–10 times in a single pass.

[1]  Philippe Dépincé,et al.  Active integration of tool deflection effects in end milling. Part 1. Prediction of milled surfaces , 2006 .

[2]  V S Rao,et al.  Effect of workpiece curvature on cutting forces and surface error in peripheral milling , 2006 .

[3]  A. Geddam,et al.  Error compensation in the end milling of pockets: a methodology , 2003 .

[4]  Suk-Hwan Suh,et al.  Incorporation of tool deflection in tool path computation: Simulation and analysis , 1996 .

[5]  Anthony Chukwujekwu Okafor,et al.  Derivation of machine tool error models and error compensation procedure for three axes vertical machining center using rigid body kinematics , 2000 .

[6]  Chana Raksiri,et al.  Geometric and force errors compensation in a 3-axis CNC milling machine , 2004 .

[7]  Yusuf Altintas,et al.  Direct adaptive control of end milling process , 1994 .

[8]  Yusuf Altintas,et al.  Mechanics and Dynamics of Ball End Milling , 1998 .

[9]  D. L. Leete.  Automatic compensation of alignment errors in machine tools , 1961 .

[10]  Yusuf Altintas,et al.  Prediction of Ball End Milling Forces , 1996 .

[11]  Y. S. Tarng,et al.  Fuzzy control of feed rate in end milling operations , 1993 .

[12]  V. S. Rao,et al.  Tool deflection compensation in peripheral milling of curved geometries , 2006 .

[13]  Philippe Dépincé,et al.  Active integration of tool deflection effects in end milling. Part 2. Compensation of tool deflection , 2006 .

[14]  Yusuf Altintas,et al.  Prediction of Milling Force Coefficients From Orthogonal Cutting Data , 1996 .

[15]  Richard E. DeVor,et al.  MECHANISTIC MODEL FOR THE PREDICTION OF THE FORCE SYSTEM IN FACE MILLING OPERATIONS. , 1984 .

[16]  M. F. DeVries,et al.  A Generalized Geometric Error Model for Multi-Axis Machines , 1987 .

[17]  Shih-Ming Wang,et al.  A new high-efficiency error compensation system for CNC multi-axis machine tools , 2006 .

[18]  Yuan Kang,et al.  An efficient error compensation system for CNC multi-axis machines , 2002 .

[19]  Taylan Altan,et al.  Feed rate optimization based on cutting force calculations in 3-axis milling of dies and molds with sculptured surfaces , 1994 .

[20]  W. Kline,et al.  The Prediction of Surface Accuracy in End Milling , 1982 .

[21]  T. Watanabe,et al.  A Control System to Improve the Accuracy of Finished Surfaces in Milling , 1983 .

[22]  Yusuf Altintas,et al.  Peripheral milling conditions for improved dimensional accuracy , 1994 .

[23]  Chao-Yin Hsiao,et al.  A method of tool path compensation for repeated machining process , 1998 .

[24]  A. Geddam,et al.  A process-design approach to error compensation in the end milling of pockets , 1999 .

[25]  Min-Yang Yang,et al.  A Tool Deflection Compensation System for End Milling Accuracy Improvement , 1998 .

[26]  Yusuf Altintas,et al.  Mechanics and dynamics of general milling cutters.: Part I: helical end mills , 2001 .