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Offsetting Curves Using Trigonometric Splines for Contour Cutting  

Gu, Jiu-long (부산대학교 기계공학부)
Yun, Jae-Deuk (부산대학교 기계공학부)
Jung, Yoong-Ho (부산대학교 기계공학부)
Publication Information
Korean Journal of Computational Design and Engineering / v.15, no.4, 2010 , pp. 253-260 More about this Journal
Abstract
This paper presents algorithms for computing offsets of freeform curves. The approach first divides the original curve into several segments at the inflexion points. Based on the obtained new control polygon and its offsets, quadratic trigonometric splines are constructed to approximate the offset curves. Finally, the shape parameter value of trigonometric spline is determined to satisfy the required tolerance. The degree of the output curve is two, independent of the original curve's degree. Because of the great controllability, the proposed method can generate a completely overestimating offset curve by adjusting the value of the shape parameter, which guarantees no overcutting in NC machining. Furthermore, it also produces the lowest number of control points compared with other works.
Keywords
Offsetting; NURBS; NC; Trigonometric; CAD/CAM;
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