臺灣博碩士論文加值系統

在複雜曲面的牙冠加工中，傳統三軸加工遇到銑削內凹區域時，必須不斷調整進刀方向以進行切削，但還是無法加工出完整的倒凹區域，導致牙冠表面及接合面精度無法達成設計需求。因此本研究發展一套新的五軸刀具路徑產生法則，以三角網格模型(STL, Stereo Lithography)為基礎，混合C-Space與向心法快速搜尋刀具軸向，建立一套自動化路徑生成的電腦輔助製造(Computer-aided manufacturing, CAM)系統應用於牙冠加工。
傳統三軸加工對於外型複雜的牙齒已不敷使用，對於牙齒倒凹部分無法達成加工需求，本論文利用STL為基礎產生五軸刀具路徑，在規劃基礎刀具路徑前，對待處理的工件模型進行轉正以減少刀具傾角變化，利用Z-Level產生等高的刀具路徑，最後利用C-Space與向心法混合規劃刀具軸向，完成一套應用於牙冠加工的五軸電腦輔助製造系統。

In a dental CAD/CAM system, when milling the concave area of the inside surface of a tooth crown, the machining direction of the tool has to be adjusted constantly in order to avoid gauging or over-cutting. For some under-cut area, the tool also needs to be tilted to machine the under-cut area, otherwise the crown may not seat properly on the abutment due to interference. The purpose of this research is to establish a new 5-axis tool path generation algorithm. Based on the triangular mesh model, a hybrid C-Space and Centroid method is proposed to quickly search the proper tool axis directions. The establishment of a computer-aided manufacturing (CAM) system for automatic tool-path generation is applied to dental crown machining.
The traditional 3-axis machining, when applied to complex surface milling of a dental crown, has never been satisfactory. It cannot produce the desired smooth and gauging free surface. In this thesis, we use the STL format to generate a 5-axis tool-path. First, the orientation of the workpiece will be corrected to reduce tool inclination changes. Secondly, the system generates the tool-path by the Z-Level algorithm. Finally, we use the proposed hybrid C-Space and Centripetal method to determine the tool axis. The integration of the above methods makes the automatic tool-path generation of the crown surface possible, which is very important for the automation of a dental CAD/CAM system.

目錄 i
圖目錄 vi
表目錄 viii
第一章 緒論 1
1.1 前言 1
1.2 研究動機 2
1.3 研究目的 3
1.4 參考文獻 4
1.5 研究方法 10
第二章 模型的轉正 11
2.1 模型轉正演算法 12
2.2 快速搜尋初始軸向 13
2.3 模型的C-Space建立 15
第三章 產生五軸刀具路徑 19
3.1 產生五軸刀具路徑步驟 19
3.2 刀具路徑的種類 22
3.3 刀具接觸點取得 30
3.4 刀具位置點的運算方法 31
第四章 刀具軸向選定 40
4.1 刀具軸向選定方式 40
4.1.1 給定刀具軸向再修正 41
4.1.2 可行空間中規劃刀軸方向 43
4.2 刀具碰撞檢測 44
4.3 刀具可行軸向演算法 49
4.4 選定刀具軸向 54
第五章 研究成果 56
5.1 NC POST 57
5.2 模型轉正 59
5.3 等高路徑產生 61
5.4 C-Space法 62
5.5 程式模擬與實際加工結果 64
5.5.1 內冠實作結果 64
5.5.2 牙冠實作結果 66
5.6 結果與討論 69
第六章 結論與未來規劃 70
6.1 結論 70
6.2 未來規劃 71
參考文獻 72

[1]K. Marciniak, "Influence of surface shape on admissible tool positions in 5-axis face milling," Computer-Aided Design, vol. 19, pp. 233-236, 1987.
[2]F. Li, X. Wang, S. Ghosh, D. Kong, T. Lai, and X. Wu, "Tool-path generation for machining sculptured surface," Journal of materials processing technology, vol. 48, pp. 811-816, 1995.
[3]R. Baptista and J. A. Simoes, "Three and five axes milling of sculptured surfaces," Journal of materials processing technology, vol. 103, pp. 398-403, 2000.
[4]P. Gray, S. Bedi, F. Ismail, N. Rao, and G. Morphy, "Comparison of 5-axis and 3-axis finish machining of hydroforming die inserts," The International Journal of Advanced Manufacturing Technology, vol. 17, pp. 562-569, 2001.
[5]H. T. Young and L. C. Chuang, "An integrated machining approach for a centrifugal impeller," The International Journal of Advanced Manufacturing Technology, vol. 21, pp. 556-563, 2003.
[6]T. D. Tang, "Algorithms for collision detection and avoidance for five-axis NC machining: a state of the art review," Computer-Aided Design, vol. 51, pp. 1-17, 2014.
[7]B. K. Choi and C. Jun, "Ball-end cutter interference avoidance in NC machining of sculptured surfaces," Computer-aided design, vol. 21, pp. 371-378, 1989.
[8]X. Ding, J. Y. Fuh, and K. S. Lee, "Interference detection for 3-axis mold machining," Computer-Aided Design, vol. 33, pp. 561-569, 2001.
[9]Y. S. Lee and T. C. Chang, "2-phase approach to global tool interference avoidance in 5-axis machining," Computer-Aided Design, vol. 27, pp. 715-729, 1995.
[10]B. K. Choi, D. H. Kim, and R. B. Jerard, "C-Space approach to tool-path generation for die and mould machining," Computer-Aided Design, vol. 29, pp. 657-669, 1997.
[11]K. Morishige, K. Kase, and Y. Takeuchi, "Collision-free tool path generation using 2-dimensional C-Space for 5-axis control machining," The International Journal of Advanced Manufacturing Technology, vol. 13, pp. 393-400, 1997.
[12]C. S. Jun, K. Cha, and Y. S. Lee, "Optimizing tool orientations for 5-axis machining by configuration-space search method," Computer-Aided Design, vol. 35, pp. 549-566, 2003.
[13]G. Elber and E. Cohen, "A unified approach to verification in 5-axis freeform milling environments," Computer-Aided Design, vol. 31, pp. 795-804, 1999.
[14]L. Zhiwei, S. Hongyao, G. Wenfeng, and F. Jianzhong, "Approximate tool posture collision-free area generation for five-axis CNC finishing process using admissible area interpolation," The International Journal of Advanced Manufacturing Technology, vol. 62, pp. 1191-1203, 2012.
[15]C. F. You and C. H. Chu, "Tool-path verification in five-axis machining of sculptured surfaces," The International Journal of Advanced Manufacturing Technology, vol. 13, pp. 248-255, 1997.
[16]C. G. Jensen, W. E. Red, and J. Pi, "Tool selection for five-axis curvature matched machining," Computer-Aided Design, vol. 34, pp. 251-266, 2002.
[17]W. Zhang, Y. Zhang, and Q. Ge, "Interference-free tool path generation for 5-axis sculptured surface machining using rational Bézier motions of a flat-end cutter," International Journal of Production Research, vol. 43, pp. 4103-4124, 2005.
[18]G. Kiswanto, B. Lauwers, and J. P. Kruth, "Gouging elimination through tool lifting in tool path generation for five-axis milling based on faceted models," The International Journal of Advanced Manufacturing Technology, vol. 32, pp. 293-309, 2007.
[19]P. Gray, S. Bedi, and F. Ismail, "Rolling ball method for 5-axis surface machining," Computer-Aided Design, vol. 35, pp. 347-357, 2003.
[20]P. J. Gray, S. Bedi, and F. Ismail, "Arc-intersect method for 5-axis tool positioning," Computer-Aided Design, vol. 37, pp. 663-674, 2005.
[21]Q. H. Wang, J. R. Li, and R. R. Zhou, "Graphics-assisted approach to rapid collision detection for multi-axis machining," The International Journal of Advanced Manufacturing Technology, vol. 30, pp. 853-863, 2006.
[22]J. E. Bobrow, "NC machine tool path generation from CSG part representations," Computer-aided design, vol. 17, pp. 69-76, 1985.
[23]I.D. Faux and M.J. Pratt, Computational geometry for design and manufacture. Ellis Horwood Ltd, 1979..
[24]G. C. Loney and T. M. Ozsoy, "NC machining of free form surfaces," Computer-Aided Design, vol. 19, pp. 85-90, 1987.
[25]B. K. Choi, J. Park, and C. Jun, "Cutter-location data optimization in 5-axis surface machining," Computer-Aided Design, vol. 25, pp. 377-386, 1993.
[26]H. Zhu, Z. Liu, and J. Fu, "Spiral tool-path generation with constant scallop height for sheet metal CNC incremental forming," The International Journal of Advanced Manufacturing Technology, vol. 54, pp. 911-919, 2011.
[27]J. S. Chen, Y. K. Huang, and M. S. Chen, "A study of the surface scallop generating mechanism in the ball-end milling process," International Journal of Machine Tools and Manufacture, vol. 45, pp. 1077-1084, 2005.
[28]B. K. Choi and R. Jerard, "Sculptured surface machiningKluwer Academic Publishers," ed: Dordrecht, 1998.
[29]E. Lee, "Contour offset approach to spiral toolpath generation with constant scallop height," Computer-Aided Design, vol. 35, pp. 511-518, 2003.
[30]H. T. Yau and C.Y. Hsu," Generating NC tool paths from random scanned data using point-based models," The International Journal of Advanced Manufacturing Technology, vol. 41,pp. 897–907,2009.
[31]H. T. Yau and C. M. Chuang, "A new approach to z-level contour machining of triangulated surface models using fillet endmills," Computer-Aided Design, vol. 37,pp. 1039–1051,2005.
[32]Q. H. Wang, J. R. Li, and H. Q. Gong, "Graphics-assisted cutter orientation correction for collision-free five-axis machining," International journal of production research, vol. 45, pp. 2875-2894, 2007.
[33]P. Kersting and A. Zabel, "Optimizing NC-tool paths for simultaneous five-axis milling based on multi-population multi-objective evolutionary algorithms," Advances in Engineering Software, vol. 40, pp. 452-463, 2009.
[34]S. Ho, S. Sarma, and Y. Adachi, "Real-time interference analysis between a tool and an environment," Computer-Aided Design, vol. 33, pp. 935-947, 2001.
[35]S. Ding, M. Mannan, and A. N. Poo, "Oriented bounding box and octree based global interference detection in 5-axis machining of free-form surfaces," Computer-Aided Design, vol. 36, pp. 1281-1294, 2004.
[36]W. Yang, H. Ding, and Y. Xiong, "Manufacturability analysis for a sculptured surface using visibility cone computation," The International Journal of Advanced Manufacturing Technology, vol. 15, pp. 317-321, 1999.
[37]M. Balasubramaniam, P. Laxmiprasad, S. Sarma, and Z. Shaikh, "Generating 5-axis NC roughing paths directly from a tessellated representation," Computer-Aided Design, vol. 32, pp. 261-277, 2000.
[38]Q. Z. Bi, Y. H. Wang, and H. Ding, "A GPU-based algorithm for generating collision-free and orientation-smooth five-axis finishing tool paths of a ball-end cutter," International Journal of Production Research, vol. 48, pp. 1105-1124, 2010.