NURBS Post-Processing of Linear Tool Path

미소직선 공구경로의 NURBS 변환

  • 김수진 (한국과학기술원 대학원 기계공학과) ;
  • 최인휴 (한국과학기술원 대학원 기계공학과) ;
  • 양민양 (한국과학기술원 기계공학과)
  • Published : 2003.07.01


NURBS (Non Uniform Rational B-Spline) is widely used in CAD system and NC data for high speed machining. Conventional CAM system changes NURBS surface to tessellated meshes or Z-map model, and produces linear tool path. The linear tool path is not good fur precise machining and high speed machining. In this paper, an algorithm to change linear tool path to NURBS one was studied and the machining result of NURBS tool path was compared with that of linear tool path. The N-post including both a post-processing and a virtual machining software was developed. The N-Post transforms linear tool path to NURBS tool path and quickly shades a machined product on OpenGL view, while comparing a machined surface with a original CAD one. A virtulal machined model of original tool path and post-processed tool path was compared to original CAD model. The machining error and machining time of post-processed NURBS tool path were investigated.


Tool Path;NURBS Interpolation;Spline Interpolation;Post-Processing;NC Machining


  1. FANUC Series 15-MB/ 16-MC/ 16i-MA Controller User Manual
  2. SIEMENSE 840D Controller User Manual
  3. Volker, and Kreidler, 1998, '5-axis High Speed NURBS Machining on a New Parallel Kinematic-Machine,' Machining Impossible Shapes. IFIP, pp. 315-324
  4. Seong, W., Choi C. H. and Song, O. S., 1999, 'A Tool path Generation for CNC Machining of Free-form Surfaces,' Journal of the Korean Society of Precision Engineering, Vol. 16, No. 4, pp. 129-137
  5. Hong, W P., Lee, S. W, Choi, H. Z. and Yang, M. Y, 2003, 'Simultaneous 3D Machining with Real-Time NURBS Interpolation,' KSME International Journal, Vol. 17, No. 3, pp. 336-342
  6. Kim, T. Wand Lee, K. W, 2001, 'Weight Control and Knot Placement for Rational B-spline Curve Interpolation,' KSME International Journal, Vol. 15, No. 2, pp. 192-198
  7. Choi, B. K., 1991, 'Surface Modeling for CAD/CAM,' Elsevier
  8. Les, P., and Wayne, T., 1995, 'The NURBS Book,' Springer
  9. Choi, B. K. and Jerard, R. B., 1998, 'Sculptured Surface Machining,' Kluwer Academic Publishers
  10. Choi, B. K., Hwang, J. S., Lee, C. S. and Jun, C. S., 1998, 'Compound Surface Modeling and Machining,' Computer-Aided Design, Vol. 20, No. 3, pp. 127-136
  11. Shpitalni, M., Koren, Y and Lo, C. C., 1994, 'Realtime Curve Interpolators,' Computer-Aided Design, Vol. 26, No. 11, pp. 832-836
  12. Yang, D. C. H. and Kong, Tom, 1994, 'Parametric Interpolator Versus Linear Interpolator for Precision CNC Machining,' Computer-Aided Design, Vol. 26, No. 3, pp. 225-234
  13. Bedi, S., Ali, I. and Quan, N., 1993, 'Advanced Interpolation Techniques for N.C. Machines' ASME Journal of Engineering for Industry, Vol. 115, pp. 329-336