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Offsetting a Region Including Islands for Tool-Path Generation

공구 경로 생성을 위한 아일랜드를 포함하는 영역의 오프셋

  • Published : 2001.12.01

Abstract

This paper presents a region offsetting algorithm for tool-path generation. The proposed region offsetting algorithm is developed by expanding the 'PWID offset algorithm [Choi and Park, 1999]'designed to offset a simple polygon. The PWID offset algorithm has three important steps; 1) remove 'local invalid ranges'by invoking a PWID test, 2) construct a raw offset owe and 3) remove 'global invalid ranges'by finding self-intersections of the raw offset cure. To develop a region offsetting algorithm, we modified the PWID offset algorithm by expanding the concept of the 'global invalid range'in the third step. The time complexity of the proposed algorithm is approximately Ο(n), where n is the number of points, and it is free of numerical errors for practical purposes. The proposed algorithm has been implemented and tested with various real regions obtained by intersecting a sculptured surface with a plane.

Keywords

Region Offset;Tool-Path Generation;PWID Offset;Pocket Machining

References

  1. Held, M., 1991, On the Compuational Geometry of Pocket Machining, Springer-Verlag, Berlin, 1991
  2. Shu Young Seok and Lee Kunwoo, 1990, 'NC Milling Tool Path Generation for Arbitary Pockets Defined by Sculptured Sufraces,' Computer Aided Design, Vol. 25, No. 5, pp. 273-284 https://doi.org/10.1016/0010-4485(90)90092-Q
  3. 김태주, 이건우, 홍성의, 1994, '옥트리를 이용한 황삭 가공경로 생성,' 대한기계학회논문집, 제 18권, 제 1 호, pp. 53-64
  4. Kalmanovich G. and Nisnevich G., 1998, 'Swift and Stable Polygon Growth and Broken Line Offset,' Computer Aided Design, Vol. 30, No. 11, pp. 847-852 https://doi.org/10.1016/S0010-4485(98)00041-4
  5. Rohmfeld, R. F., 1998, 'IGB-Offset for Plane Cruve Loop Removal by Scanning of Interval Sequences,' Computer Aided Geometric Design, Vol. 15, pp. 339-375 https://doi.org/10.1016/S0167-8396(97)00038-1
  6. Chiang, C. S., Hoffman, C. M. and Lynch, R. E., 1991, 'How to Compute Offsets without Self Intersection,' In SPIE Conf Proc Curve and Surfaces in Computer Vision and Graphics Ⅱ, Boston, MA, pp. 76-87 https://doi.org/10.1117/12.135136
  7. Kokichi Sugihara, 1998, 'Degeneracy and Instability in Geometric Computation,' In Proc.of IEIP WG5.2 GEO-6 Conference in Tokyo Unversity, Dec. 7-9, pp. 5-15
  8. Persson, H., 1978, 'NC Machining of Arbitrary Shaped Pockets,' Computer Aided Design, Vol. 10, No. 3, pp. 169-174 https://doi.org/10.1016/0010-4485(78)90141-0
  9. Choi, B. K. and Kim, B. H., 1997, 'Die-Cavity Pocketing via Cutting Simulation,' Computer Aided Design, Vol. 29, No. 12, pp. 837-846 https://doi.org/10.1016/S0010-4485(97)00031-6
  10. Hansen, A. and Arbab, F., 1992, 'An Algorithm for Generating NC Tool Path for Arbitrary Shaped Pockets with Islands.' ACM Transactions on Graphics, Vol. 11, No. 2, pp. 152-182 https://doi.org/10.1145/130826.130832
  11. Held, M., Lukacs, G., and Andor. L., 1994, 'Pocket Machining Based on Contour-Parallel Tool Paths Generated by Means of Proxmity Maps,' Computer Aided Design, Vol. 26, No. 3, pp. 189-203 https://doi.org/10.1016/0010-4485(94)90042-6
  12. Park, SangC., Chung, Y. C., 2001, 'Offset Tool-Path Liking for pocket Machining,' accepted for publication in Computer Aided Design
  13. Park, SangC., Choi, B. K., 2001, 'Uncut-Free Pocketing for Tool-Path Generation Using Pair -Wise Offset Algorithm,' Computer Aided Design, Vol. 33, No. 10, pp. 739-46 https://doi.org/10.1016/S0010-4485(00)00109-3
  14. Park, SangC., Shin, H. and Choi, B. K., 1998, 'A Sweep Line Algorithm for Polygonal Chain Intersection and Its Applications,' In Proc. of IEIP WG5.2 GEO-6 Conference in Tokyo University, Dec. 7-9, pp. 187-195
  15. Choi, B. K. and Park SangC., 1999, 'A Pair-Wise Offset Algorithm for 2D Point-Sequence,' Computer Aied Design, Vol. 31, No. 12, pp. 735-45 https://doi.org/10.1016/S0010-4485(99)00060-3